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Sample records for material stress-strain response

  1. Stress-strain response of plastic waste mixed soil.

    Science.gov (United States)

    Babu, G L Sivakumar; Chouksey, Sandeep Kumar

    2011-03-01

    Recycling plastic waste from water bottles has become one of the major challenges worldwide. The present study provides an approach for the use plastic waste as reinforcement material in soil. The experimental results in the form of stress-strain-pore water pressure response are presented. Based on experimental test results, it is observed that the strength of soil is improved and compressibility reduced significantly with addition of a small percentage of plastic waste to the soil. The use of the improvement in strength and compressibility response due to inclusion of plastic waste can be advantageously used in bearing capacity improvement and settlement reduction in the design of shallow foundations. Copyright © 2010 Elsevier Ltd. All rights reserved.

  2. Representative Stress-Strain Curve by Spherical Indentation on Elastic-Plastic Materials

    Directory of Open Access Journals (Sweden)

    Chao Chang

    2018-01-01

    Full Text Available Tensile stress-strain curve of metallic materials can be determined by the representative stress-strain curve from the spherical indentation. Tabor empirically determined the stress constraint factor (stress CF, ψ, and strain constraint factor (strain CF, β, but the choice of value for ψ and β is still under discussion. In this study, a new insight into the relationship between constraint factors of stress and strain is analytically described based on the formation of Tabor’s equation. Experiment tests were performed to evaluate these constraint factors. From the results, representative stress-strain curves using a proposed strain constraint factor can fit better with nominal stress-strain curve than those using Tabor’s constraint factors.

  3. Relationship between fatigue life in the creep-fatigue region and stress-strain response

    Science.gov (United States)

    Berkovits, A.; Nadiv, S.

    1988-01-01

    On the basis of mechanical tests and metallographic studies, strainrange partitioned lives were predicted by introducing stress-strain materials parameters into the Universal Slopes Equation. This was the result of correlating fatigue damage mechanisms and deformation mechanisms operating at elevated temperatures on the basis of observed mechanical and microstructural behavior. Correlation between high temperature fatigue and stress strain properties for nickel base superalloys and stainless steel substantiated the method. Parameters which must be evaluated for PP- and CC- life are the maximum stress achievable under entirely plastic and creep conditions respectively and corresponding inelastic strains, and the two more pairs of stress strain parameters must be ascertained.

  4. On the derivative of the stress-strain relation in a no-tension material

    Czech Academy of Sciences Publication Activity Database

    Padovani, C.; Šilhavý, Miroslav

    2017-01-01

    Roč. 22, č. 7 (2017), s. 1606-1618 ISSN 1081-2865 Institutional support: RVO:67985840 Keywords : no-tension material * stress-strain relation Subject RIV: BA - General Mathematics OBOR OECD: Applied mathematics Impact factor: 2.953, year: 2016 http:// journals .sagepub.com/doi/10.1177/1081286515571786

  5. An improved Armstrong-Frederick-Type Plasticity Model for Stable Cyclic Stress-Strain Responses Considering Nonproportional Hardening

    Science.gov (United States)

    Li, Jing; Zhang, Zhong-ping; Li, Chun-wang

    2018-03-01

    This paper modified an Armstrong-Frederick-type plasticity model for investigating the stable cyclic deformation behavior of metallic materials with different sensitivity to nonproportional loadings. In the modified model, the nonproportionality factor and nonproportional cyclic hardening coefficient coupled with the Jiang-Sehitoglu incremental plasticity model were used to estimate the stable stress-strain responses of the two materials (1045HR steel and 304 stainless steel) under various tension-torsion strain paths. A new equation was proposed to calculate the nonproportionality factor on the basis of the minimum normal strain range. Procedures to determine the minimum normal strain range were presented for general multiaxial loadings. Then, the modified model requires only the cyclic strain hardening exponent and cyclic strength coefficient to determine the material constants. It is convenient for predicting the stable stress-strain responses of materials in engineering application. Comparisons showed that the modified model can reflect the effect of nonproportional cyclic hardening well.

  6. Effect of loading history on cyclic stress-strain response

    Czech Academy of Sciences Publication Activity Database

    Kunz, Ludvík; Lukáš, Petr; Weiss, B.; Melisova, D.

    2001-01-01

    Roč. 314, 1/2 (2001), s. 1-6 ISSN 0921-5093. [TMS Annual Meeting. Nashville, 12.03.2000-16.03.2000] R&D Projects: GA AV ČR IBS2041001 Institutional research plan: CEZ:AV0Z2041904 Keywords : cyclic plasticity * loading history * mean stress Subject RIV: JL - Materials Fatigue, Friction Mechanics Impact factor: 0.978, year: 2001

  7. On the cyclic stress-strain behavior and low cycle fatigue of aerospace materials

    Science.gov (United States)

    Burbach, J.

    1972-01-01

    The elastic-plastic deformation behavior under cyclic stress of a number of different engineering materials was experimentally investigated with the aid of high-precision methods of measuring, some of which had been newly developed. Experiments made with a variety of steels, the titanium alloy Ti-A16-V4, a cobalt (tungsten) alloy, the high-temperature material Nimonic 90 and Dural (A1-Cu) are reported. The theory given in an attempt to explain these experiments is aimed at finding general formulas for the cyclic stress-strain behavior materials.

  8. Prediction of thermal and mechanical stress-strain responses of TMC's subjected to complex TMF histories

    Science.gov (United States)

    Johnson, W. S.; Mirdamadi, M.

    1994-01-01

    This paper presents an experimental and analytical evaluation of cross-plied laminates of Ti-15V-3Cr-3Al-3Sn (Ti-15-3) matrix reinforced with continuous silicon-carbide fibers (SCS-6) subjected to a complex TMF loading profile. Thermomechanical fatigue test techniques were developed to conduct a simulation of a generic hypersonic flight profile. A micromechanical analysis was used. The analysis predicts the stress-strain response of the laminate and of the constituents in each ply during thermal and mechanical cycling by using only constituent properties as input. The fiber was modeled as elastic with transverse orthotropic and temperature-dependent properties. The matrix was modeled using a thermoviscoplastic constitutive relation. The fiber transverse modulus was reduced in the analysis to simulate the fiber-matrix interface failures. Excellent correlation was found between measured and predicted laminate stress-strain response due to generic hypersonic flight profile when fiber debonding was modeled.

  9. Biaxial failure criteria and stress-strain response for concrete of containment structure

    International Nuclear Information System (INIS)

    Lee, S. K.; Woo, S. K.; Song, Y. C.; Kweon, Y. K.; Cho, C. H.

    2001-01-01

    Biaxial failure criteria and stress-strain response for plain concrete of containment structure on nuclear power plants are studied under uniaxial and biaxial stress(compression-compression, compression-tension, and tension-tension combined stress). The concrete specimens of a square plate type are used for uniaxial and biaxial loading. The experimental data indicate that the strength of concrete under biaxial compression, f 2 /f 1 =-1/-1, is 17 percent larger than under uniaxial compression and the poisson's ratio of concrete is 0.1745. On the base of the results, a biaxial failure envelope for plain concrete that the uniaxial strength is 5660 psi are provided, and the biaxial failure behaviors for three biaxial loading areas are plotted respectively. And, various analytical equations having the reliability are proposed for representations of the biaxial failure criteria and stress-strain response curves of concrete

  10. Random cyclic stress-strain responses of a stainless steel pipe-weld metal. II. A modeling

    International Nuclear Information System (INIS)

    Zhao, Y.X.; Wang, J.N.

    2000-01-01

    For pt.I see ibid., vol.199, p.303-14, 2000. This paper pays special attention to an issue that there is a significant scatter of the stress-strain responses of a nuclear engineering material, 1Cr18Ni9Ti stainless steel pipe-weld metal. Efforts are made to reveal the random fatigue damage character by fracture surface observations and to model the random responses by introducing probability-based stress-strain curves of Ramberg-Osgood relation and its modified form. Results reveal that the fatigue damage is subjected to, 3-D interacting and involved microcracks. The three stages, namely microstructural short cracks (MSC), physical short cracks (PSC) and long cracks (LC) subdivided by Miller and de los Rios, can give a good characterization of the damage process. Both micro- and macro-behaviour of the material have the character of three stages. The 3-D effects are strong in the MSC stage, tend to a gradual decrease in the PSC stage, and then show saturation after going to the LC stage. Intrinsic causes of the random behaviour are the difference and evolution of the microstructural conditions ahead of the dominant crack tips. The 'effectively short fatigue crack criterion' introduced by Zhao et al. in observing the material surface short crack behaviour could facilitate an understanding of the mechanism of interaction and evolution. Based on the previous obtained appropriate assumed distribution, normal model, for the cyclic stress amplitude, the probability-based curves are approximated by the mean value and standard deviation cyclic stress-strain curves. Then, fatigue analysis at arbitrarily given reliability can be conveniently made according to the normal distribution function. To estimate these curves, a maximum likelihood method is developed. The analysis reveals that the curves could give a good modeling of the random responses of material. (orig.)

  11. On stress/strain shielding and the material stiffness paradigm for dental implants.

    Science.gov (United States)

    Korabi, Raoof; Shemtov-Yona, Keren; Rittel, Daniel

    2017-10-01

    Stress shielding considerations suggest that the dental implant material's compliance should be matched to that of the host bone. However, this belief has not been confirmed from a general perspective, either clinically or numerically. To characterize the influence of the implant stiffness on its functionality using the failure envelope concept that examines all possible combinations of mechanical load and application angle for selected stress, strain and displacement-based bone failure criteria. Those criteria represent bone yielding, remodeling, and implant primary stability, respectively MATERIALS AND METHODS: We performed numerical simulations to generate failure envelopes for all possible loading configurations of dental implants, with stiffness ranging from very low (polymer) to extremely high, through that of bone, titanium, and ceramics. Irrespective of the failure criterion, stiffer implants allow for improved implant functionality. The latter reduces with increasing compliance, while the trabecular bone experiences higher strains, albeit of an overall small level. Micromotions remain quite small irrespective of the implant's stiffness. The current paradigm favoring reduced implant material's stiffness out of concern for stress or strain shielding, or even excessive micromotions, is not supported by the present calculations, that point exactly to the opposite. © 2017 Wiley Periodicals, Inc.

  12. Flow stress asymmetry and cyclic stress--strain response in a BCC Ti--V alloy

    International Nuclear Information System (INIS)

    Koss, D.A.; Wojcik, C.C.

    1976-01-01

    The cyclic stress-strain response of relatively stable bcc β-phase Ti--40 percent V alloy single crystals was studied. Flow stress asymmetry found in the alloy is attributed to the fact that screw dislocations, when gliding on a (211) plane, are more mobile in the twinning direction than in the antitwinning direction. Thus the flow stress of the crystal is greater when it is sheared in the antitwinning direction than in the twinning direction (the latter case results when crystals of the 100 orientation are stressed in tension and those of the 110 orientation are stressed in compression). Such behavior can be a result of the core of a screw dislocation being asymmetric under stress which causes the flow stress asymmetry observed. It should be noted that screw dislocations dominate the low temperature deformation structure of Ti-40V, which strongly suggests deformation is controlled by screw dislocation motion. The observation in Mo that the microyield stress is independent of crystal orientation could be a result of edge dislocation motion controlling microyield in that instance and this observation would not be inconsistent with screw dislocation motion controlling the macroscopic (epsilon/sub p/ greater than 0.05 percent) deformation measured here

  13. Simulation of tensile stress-strain properties of irradiated type 316 SS by heavily cold-worked material

    International Nuclear Information System (INIS)

    Muto, Yasushi; Jitsukawa, Shiro; Hishinuma, Akimichi

    1995-07-01

    Type 316 stainless steel is one of the most promising candidate materials to be used for the structural parts of plasma facing components in the nuclear fusion reactor. The neutron irradiation make the material brittle and reduces its uniform elongation to almost zero at heavy doses. In order to apply such a material of reduced ductility to structural components, the structural integrity should be examined and assured by the fracture mechanics. The procedure requires a formulated stress-strain relationship. However, the available irradiated tensile test data are very limited at present, so that the cold-worked material was used as a simulated material in this study. Property changes of 316 SS, that is, a reduction of uniform elongation and an enhancement of yield stress are seemingly very similar for both the irradiated 316 SS and the cold-worked one. The specimens made of annealed 316 SS, 20% (or 15%) cold worked one and 40% cold worked one were prepared. After the formulation of stress strain behavior, the equation for the cold-worked 316 SS was fitted to the data on irradiated material under the assumption that the yield stress is the same for both materials. In addition, the upper limit for the plastic strain was introduced using the data on the irradiated material. (author)

  14. Random cyclic stress-strain responses of a stainless steel pipe-weld metal. I. A statistical investigation

    International Nuclear Information System (INIS)

    Zhao, Y.X.; Wang, J.N.

    2000-01-01

    For pt.II see ibid., vol.199, p.315-26, 2000. This paper pays a special attention to the issue that there is a significant scatter of the stress-strain responses of a nuclear engineering material, 1Cr18Ni9Ti stainless steel pipe-weld metal. Statistical investigation is made to the cyclic stress amplitudes of this material. Three considerations are given. They consist of the total fit, the consistency with fatigue physics and the safety in practice of the seven commonly used statistical distributions, namely Weibull (two- and three-parameter), normal, lognormal, extreme minimum value, extreme maximum value and exponential. Results reveal that the data follow meanwhile the seven distributions but the local effects of the distributions yield a significant difference. Any of the normal, lognormal, extreme minimum value and extreme maximum value distributions might be an appropriate assumed distribution for characterizing the data. The normal and extreme minimum models are excellent. Other distributions do not fit the data as they violate two or three of the mentioned considerations. (orig.)

  15. Cyclic stress-strain behavior of polymeric nonwoven structures for the use as artificial leaflet material for transcatheter heart valve prostheses

    Directory of Open Access Journals (Sweden)

    Arbeiter Daniela

    2017-09-01

    Full Text Available Xenogenic leaflet material, bovine and porcine pericardium, is widely used for the fabrication of surgically implanted and transcatheter heart valve prostheses. As a biological material, long term durability of pericardium is limited due to calcification, degeneration and homogeneity. Therefore, polymeric materials represent a promising approach for a next generation of artificial heart valve leaflets with improved durability. Within the current study we analyzed the mechanical performance of polymeric structures based on elastomeric materials. Polymeric cast films were prepared and nonwovens were manufactured in an electrospinning process. Analysis of cyclic stress-strain behavior was performed, using a universal testing machine. The uniaxial cyclic tensile experiments of the elastomeric samples yielded a non-linear elastic response due to viscoelastic behavior with hysteresis. Equilibrium of stress-strain curves was found after a specific number of cycles, for cast films and nonwovens, respectively. In conclusion, preconditioning was found obligatory for the evaluation of the mechanical performance of polymeric materials for the use as artificial leaflet material for heart valve prostheses.

  16. Theoretical Conversions of Different Hardness and Tensile Strength for Ductile Materials Based on Stress-Strain Curves

    Science.gov (United States)

    Chen, Hui; Cai, Li-Xun

    2018-04-01

    Based on the power-law stress-strain relation and equivalent energy principle, theoretical equations for converting between Brinell hardness (HB), Rockwell hardness (HR), and Vickers hardness (HV) were established. Combining the pre-existing relation between the tensile strength ( σ b ) and Hollomon parameters ( K, N), theoretical conversions between hardness (HB/HR/HV) and tensile strength ( σ b ) were obtained as well. In addition, to confirm the pre-existing σ b -( K, N) relation, a large number of uniaxial tensile tests were conducted in various ductile materials. Finally, to verify the theoretical conversions, plenty of statistical data listed in ASTM and ISO standards were adopted to test the robustness of the converting equations with various hardness and tensile strength. The results show that both hardness conversions and hardness-strength conversions calculated from the theoretical equations accord well with the standard data.

  17. Effects of strain rate, mixing ratio, and stress-strain definition on the mechanical behavior of the polydimethylsiloxane (PDMS) material as related to its biological applications.

    Science.gov (United States)

    Khanafer, Khalil; Duprey, Ambroise; Schlicht, Marty; Berguer, Ramon

    2009-04-01

    Tensile tests on Polydimethylsiloxane (PDMS) materials were conducted to illustrate the effects of mixing ratio, definition of the stress-strain curve, and the strain rate on the elastic modulus and stress-strain curve. PDMS specimens were prepared according to the ASTM standards for elastic materials. Our results indicate that the physiological elastic modulus depends strongly on the definition of the stress-strain curve, mixing ratio, and the strain rate. For various mixing ratios and strain rates, true stress-strain definition results in higher stress and elastic modulus compared with engineering stress-strain and true stress-engineering strain definitions. The elastic modulus increases as the mixing ratio increases up-to 9:1 ratio after which the elastic modulus begins to decrease even as the mixing ratio continues to increase. The results presented in this study will be helpful to assist the design of in vitro experiments to mimic blood flow in arteries and to understand the complex interaction between blood flow and the walls of arteries using PDMS elastomer.

  18. Analysis of stress-strain relationship in materials containing voids by means of plastic finite element method

    International Nuclear Information System (INIS)

    Shiraishi, Haruki; Tabuchi, Masaaki

    2000-01-01

    Applying the finite element method in two dimensions, an analysis is performed to derive the stress-strain relationship of material containing voids in matrix, and which is subjected to large deformation. The conditions assumed for the analysis are applicability of continuum body mechanics, Mises yield criterion, J2 flow theory, power work-hardening, plane stress in two-dimensional system and uniform cyclically recurring void distribution. Taking as example a case of material presenting 0.3 work-hardening, it is indicated from the analysis that: With voids arrayed in square lattice, total elongation would be little affected by change in void size; With a void spacing in lattice of 10 μ m, a uniform elongation 12-14% should be obtained in a wide range of void sizes from 0.01 to 8.0 μm; Tensile strength should start to lower at a void areal fraction of around 1%; A sharply lowered uniform elongation of a level far below 1% should be presented by material of low work-hardening exponent. The severe decline of ductility seen with 316 stainless steel upon neutron irradiation at temperatures around 600 K is interpreted as resulting from a combination of low work-hardening and the presence of voids in matrix. (author)

  19. Studies on Stress-Strain Relationships of Polymeric Materials Used in Space Applications

    Science.gov (United States)

    Jana, Sadhan C.; Freed, Alan

    2002-01-01

    A two-year research plan was undertaken in association with Polymers Branch, NASA Glenn Research Center, to carry out experimental and modeling work relating stress and strain behavior of polymeric materials, especially elastomers and vulcanized rubber. An experimental system based on MTS (Mechanical Testing and Simulation) A/T-4 test facility environment has been developed for a broader range of polymeric materials in addition to a design of laser compatible temperature control chamber for online measurements of various strains. Necessary material processing has been accomplished including rubber compounding and thermoplastic elastomer processing via injection molding. A broad suite of testing methodologies has been identified to reveal the complex non-linear mechanical behaviors of rubbery materials when subjected to complex modes of deformation. This suite of tests required the conceptualization, design and development of new specimen geometries, test fixtures, and test systems including development of a new laser based technique to measure large multi-axial deformations. Test data has been generated for some of these new fixtures and has revealed some complex coupling effects generated during multi-axial deformations. In addition, fundamental research has been conducted concerning the foundation principles of rubber thermodynamics and resulting theories of rubber elasticity. Studies have been completed on morphological properties of several thermoplastic elastomers. Finally, a series of steps have been identified to further advance the goals of NASA's ongoing effort.

  20. MM99.70 - MODELS FOR FRICTION AND MATERIAL STRESS STRAIN HARDENING IN COLD FORMING

    DEFF Research Database (Denmark)

    Eriksen, Morten

    1999-01-01

    and tool temperature for four different combination of basic material, conversion layer and lubricant. Furthermore flow stress curves for aluminium, steel and stainless steel are given at varying slug temperatures in the range which can be reached in cold forming (25-200C).The documentation is divided...

  1. Stress-strain relationship and XRD line broadening in [0001] textured hexagonal polycrystalline materials

    International Nuclear Information System (INIS)

    Yokoyama, Ryouichi

    2011-01-01

    Stress analysis with X-ray diffraction (XRD) for hexagonal polycrystalline materials in the Laue classes 6/mmm and 6/m has been studied on the basis of the crystal symmetry of the constituent crystallites which was proposed by R. Yokoyama and J. Harada ['Re-evaluation of formulae for X-ray stress analysis in polycrystalline specimens with fibre texture', Journal of Applied Crystallography, Vol.42, pp.185-191 (2009)]. The relationship between the stress and strain observable by XRD in a hexagonal polycrystalline material with [0001] fibre texture was formulated in terms of the elastic compliance defined for its single crystal. As a result, it was shown that the average strains obtained in the crystallites for both symmetries of 6/mmm and 6/m are different from each other under the triaxial or biaxial stress field. Then, it turned out that the line width of XRD changes depending on the measurement direction. (author)

  2. Characterization of the Mechanical Stress-Strain Performance of Aerospace Alloy Materials Using Frequency-Domain Photoacoustic Ultrasound and Photothermal Methods: An FEM Approach

    Science.gov (United States)

    Huan, Huiting; Mandelis, Andreas; Liu, Lixian

    2018-04-01

    Determining and keeping track of a material's mechanical performance is very important for safety in the aerospace industry. The mechanical strength of alloy materials is precisely quantified in terms of its stress-strain relation. It has been proven that frequency-domain photothermoacoustic (FD-PTA) techniques are effective methods for characterizing the stress-strain relation of metallic alloys. PTA methodologies include photothermal (PT) diffusion and laser thermoelastic photoacoustic ultrasound (PAUS) generation which must be separately discussed because the relevant frequency ranges and signal detection principles are widely different. In this paper, a detailed theoretical analysis of the connection between thermoelastic parameters and stress/strain tensor is presented with respect to FD-PTA nondestructive testing. Based on the theoretical model, a finite element method (FEM) was further implemented to simulate the PT and PAUS signals at very different frequency ranges as an important analysis tool of experimental data. The change in the stress-strain relation has an impact on both thermal and elastic properties, verified by FEM and results/signals from both PT and PAUS experiments.

  3. Evaluation of fracture toughness of vessel materials using small-size specimens and full stress-strain curves

    Energy Technology Data Exchange (ETDEWEB)

    Lebedev, A A; Chausov, N G [Akademyiya Nauk Ukrayini, Kiev (Ukraine)

    1994-12-31

    Physically substantiated dependences between crack resistance characteristics determined by the parameters of descending sections of full stress-strain curves and stressed state rigidity at crack initiation moment, have been experimentally obtained. The possibility of crack resistance reliable estimation based on full stress-strain obtained using small-size specimens with different concentrators, has thus been experimentally substantiated. Results obtained by the method and actual temperature dependence of irradiated steel 15X2NMFA crack resistance characteristics, agreed well. 2 refs., 7 figs.

  4. Comparison between the Norton - and Mukherjee constitutive equations in the determination of stress - strain analysis of a material under creep

    International Nuclear Information System (INIS)

    Bevilacqua, L.; Feijoo, R.A.; Freire, J.L.; Miranda, P.E.V. de; Monteiro, E.; Silveira, T.L. da; Taroco, E.

    1981-06-01

    The Norton and Mukherjee constitutive equations are used to approximate the experimental results of creep in AISI 304 steel. Both equations are applied to the stress-strain analysis of a rotating disk with a concentric circular hole. From the design point of view it is shown that the stresses obtained with both equations are equivalents, which is not true for the velocities. (Author) [pt

  5. A deep learning approach to estimate chemically-treated collagenous tissue nonlinear anisotropic stress-strain responses from microscopy images.

    Science.gov (United States)

    Liang, Liang; Liu, Minliang; Sun, Wei

    2017-11-01

    Biological collagenous tissues comprised of networks of collagen fibers are suitable for a broad spectrum of medical applications owing to their attractive mechanical properties. In this study, we developed a noninvasive approach to estimate collagenous tissue elastic properties directly from microscopy images using Machine Learning (ML) techniques. Glutaraldehyde-treated bovine pericardium (GLBP) tissue, widely used in the fabrication of bioprosthetic heart valves and vascular patches, was chosen to develop a representative application. A Deep Learning model was designed and trained to process second harmonic generation (SHG) images of collagen networks in GLBP tissue samples, and directly predict the tissue elastic mechanical properties. The trained model is capable of identifying the overall tissue stiffness with a classification accuracy of 84%, and predicting the nonlinear anisotropic stress-strain curves with average regression errors of 0.021 and 0.031. Thus, this study demonstrates the feasibility and great potential of using the Deep Learning approach for fast and noninvasive assessment of collagenous tissue elastic properties from microstructural images. In this study, we developed, to our best knowledge, the first Deep Learning-based approach to estimate the elastic properties of collagenous tissues directly from noninvasive second harmonic generation images. The success of this study holds promise for the use of Machine Learning techniques to noninvasively and efficiently estimate the mechanical properties of many structure-based biological materials, and it also enables many potential applications such as serving as a quality control tool to select tissue for the manufacturing of medical devices (e.g. bioprosthetic heart valves). Copyright © 2017 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.

  6. Back-propagation neural network-based approximate analysis of true stress-strain behaviors of high-strength metallic material

    International Nuclear Information System (INIS)

    Doh, Jaeh Yeok; Lee, Jong Soo; Lee, Seung Uk

    2016-01-01

    In this study, a Back-propagation neural network (BPN) is employed to conduct an approximation of a true stress-strain curve using the load-displacement experimental data of DP590, a high-strength material used in automobile bodies and chassis. The optimized interconnection weights are obtained with hidden layers and output layers of the BPN through intelligent learning and training of the experimental data; by using these weights, a mathematical model of the material's behavior is suggested through this feed-forward neural network. Generally, the material properties from the tensile test cannot be acquired until the fracture regions, since it is difficult to measure the cross-section area of a specimen after diffusion necking. For this reason, the plastic properties of the true stress-strain are extrapolated using the weighted-average method after diffusion necking. The accuracies of BPN-based meta-models for predicting material properties are validated in terms of the Root mean square error (RMSE). By applying the approximate material properties, the reliable finite element solution can be obtained to realize the different shapes of the finite element models. Furthermore, the sensitivity analysis of the approximate meta-model is performed using the first-order approximate derivatives of the BPN and is compared with the results of the finite difference method. In addition, we predict the tension velocity's effect on the material property through a first-order sensitivity analysis.

  7. A THM stress-strain framework for modelling the performance of argillaceous materials in deep repositories for radioactive waste

    International Nuclear Information System (INIS)

    Laloui, L.; Francois, B.

    2007-01-01

    In the scenarios for deep, geological nuclear-waste repositories, clayey soils will be hydrated, heated, cooled and dried. The numerical modelling of these mechanical processes is a key issue. Performance assessment of deep repositories for heat-generating radioactive waste would benefit from improvements in mechanical stress-strain constitutive modelling of the coupled thermo-hydro-mechanical behaviour. The presented framework allows progress in understanding the most involved phenomena relevant to nuclear-waste repositories and their coupled nature. It could be used both in the design and in the performance assessment of repositories. It may be applied to disposal in clay formations and to hard-rock repositories where artificially compacted clay is to be used as buffer and backfill. Such a constitutive framework may help in understanding some unexplained or controversial behaviours and in defining experimental programmes to answer key questions. (author)

  8. On generalization uniaxial stress-strain relation

    International Nuclear Information System (INIS)

    Sahay, C.; Dubey, R.N.

    1980-01-01

    Different forms of constitutive relations have been advanced for elastic, plastic and elastic-plastic behaviour of materials. It is shown that the various forms of the stress-strain relationship are specialized forms of generalization of a single stress-strain relation. For example, it is shown how the laws of elastic deformation, and the incremental and total deformation relationship for plastic behaviour are derivable from the Ramberg-Osgood relation. (orig.)

  9. BILAM: a composite laminate failure-analysis code using bilinear stress-strain approximations

    Energy Technology Data Exchange (ETDEWEB)

    McLaughlin, P.V. Jr.; Dasgupta, A.; Chun, Y.W.

    1980-10-01

    The BILAM code which uses constant strain laminate analysis to generate in-plane load/deformation or stress/strain history of composite laminates to the point of laminate failure is described. The program uses bilinear stress-strain curves to model layer stress-strain behavior. Composite laminates are used for flywheels. The use of this computer code will help to develop data on the behavior of fiber composite materials which can be used by flywheel designers. In this program the stress-strain curves are modelled by assuming linear response in axial tension while using bilinear approximations (2 linear segments) for stress-strain response to axial compressive, transverse tensile, transverse compressive and axial shear loadings. It should be noted that the program attempts to empirically simulate the effects of the phenomena which cause nonlinear stress-strain behavior, instead of mathematically modelling the micromechanics involved. This code, therefore, performs a bilinear laminate analysis, and, in conjunction with several user-defined failure interaction criteria, is designed to provide sequential information on all layer failures up to and including the first fiber failure. The modus operandi is described. Code BILAM can be used to: predict the load-deformation/stress-strain behavior of a composite laminate subjected to a given combination of in-plane loads, and make analytical predictions of laminate strength.

  10. Atlas of stress-strain curves

    CERN Document Server

    2002-01-01

    The Atlas of Stress-Strain Curves, Second Edition is substantially bigger in page dimensions, number of pages, and total number of curves than the previous edition. It contains over 1,400 curves, almost three times as many as in the 1987 edition. The curves are normalized in appearance to aid making comparisons among materials. All diagrams include metric (SI) units, and many also include U.S. customary units. All curves are captioned in a consistent format with valuable information including (as available) standard designation, the primary source of the curve, mechanical properties (including hardening exponent and strength coefficient), condition of sample, strain rate, test temperature, and alloy composition. Curve types include monotonic and cyclic stress-strain, isochronous stress-strain, and tangent modulus. Curves are logically arranged and indexed for fast retrieval of information. The book also includes an introduction that provides background information on methods of stress-strain determination, on...

  11. Stress-strain relation of bentonite at undrained shear. Laboratory tests to investigate the influence of material composition and test technique

    Energy Technology Data Exchange (ETDEWEB)

    Dueck, Ann; Boergesson, Lennart; Johannesson, Lars-Erik (Clay Technology AB, Lund (Sweden))

    2010-12-15

    This report describes a laboratory study conducted to update the material model of the buffer material used in the analyses of the effect of a rock shear through a deposition hole. The study considers some new conditions and is especially focused on the reference case with MX-80Ca developed for SR-Site (MX-80 ion exchanged to Ca). The material model is based on relations between density, swelling pressure, shear strength and rate of strain. The reference model is described by Boergesson et al. (2010). The laboratory study is focused on undrained stress-strain-strength properties, which have been studied mainly by conducting triaxial tests and unconfined compression tests. The test results are compared to the earlier measurements and models which show that the new results fit very well into the general picture and models. For the new conditions suitable values of constants included in the model are proposed

  12. Stress-strain relation of bentonite at undrained shear. Laboratory tests to investigate the influence of material composition and test technique

    International Nuclear Information System (INIS)

    Dueck, Ann; Boergesson, Lennart; Johannesson, Lars-Erik

    2010-12-01

    This report describes a laboratory study conducted to update the material model of the buffer material used in the analyses of the effect of a rock shear through a deposition hole. The study considers some new conditions and is especially focused on the reference case with MX-80Ca developed for SR-Site (MX-80 ion exchanged to Ca). The material model is based on relations between density, swelling pressure, shear strength and rate of strain. The reference model is described by Boergesson et al. (2010). The laboratory study is focused on undrained stress-strain-strength properties, which have been studied mainly by conducting triaxial tests and unconfined compression tests. The test results are compared to the earlier measurements and models which show that the new results fit very well into the general picture and models. For the new conditions suitable values of constants included in the model are proposed

  13. Neutron diffraction investigation of hysteresis reduction and increase in linearity in the stress-strain response of superelastic NiTi

    International Nuclear Information System (INIS)

    Rathod, C.R.; Clausen, B.; Bourke, M.A.M.; Vaidyanathan, R.

    2006-01-01

    In situ neutron diffraction measurements during loading have been performed on plastically deformed superelastic NiTi samples. The measurements observed retained B19 ' phase in the unloaded state as a result of the plastic deformation in otherwise completely B2 phase samples. A reversible stress-induced B2-B19 ' transformation on application and removal of stress occurred in the presence of this retained B19 ' phase. The amount and orientation of this retained B19 ' phase changed with cycling. Such direct atomic scale observations in the bulk are used here for the first time to qualitatively elucidate the macroscopic stress-strain response in plastically deformed superelastic NiTi

  14. Feasibility study on measuring axial and transverse stress/strain components in composite materials using Bragg sensors

    Science.gov (United States)

    Luyckx, G.; Degrieck, J.; De Waele, W.; Van Paepegem, W.; Van Roosbroeck, J.; Chah, K.; Vlekken, J.; McKenzie, I.; Obst, A.

    2017-11-01

    A fibre optic sensor design is proposed for simultaneously measuring the 3D stress (or strain) components and temperature inside thermo hardened composite materials. The sensor is based on two fibre Bragg gratings written in polarisation maintaining fibre. Based on calculations of the condition number, it will be shown that reasonable accuracies are to be expected. First tests on the bare sensors and on the sensors embedded in composite material, which confirm the expected behaviour, will be presented.

  15. A kinematic hardening constitutive model for the uniaxial cyclic stress-strain response of magnesium sheet alloys at room temperature

    Science.gov (United States)

    He, Zhitao; Chen, Wufan; Wang, Fenghua; Feng, Miaolin

    2017-11-01

    A kinematic hardening constitutive model is presented, in which a modified form of von Mises yield function is adopted, and the initial asymmetric tension and compression yield stresses of magnesium (Mg) alloys at room temperature (RT) are considered. The hardening behavior was classified into slip, twinning, and untwinning deformation modes, and these were described by two forms of back stress to capture the mechanical response of Mg sheet alloys under cyclic loading tests at RT. Experimental values were obtained for AZ31B-O and AZ31B sheet alloys under both tension-compression-tension (T-C-T) and compression-tension (C-T) loadings to calibrate the parameters of back stresses in the proposed model. The predicted parameters of back stresses in the twinning and untwinning modes were expressed as a cubic polynomial. The predicted curves based on these parameters showed good agreement with the tests.

  16. A comparative study on the elastic modulus of polyvinyl alcohol sponge using different stress-strain definitions.

    Science.gov (United States)

    Karimi, Alireza; Navidbakhsh, Mahdi; Alizadeh, Mansour; Razaghi, Reza

    2014-10-01

    There have been different stress-strain definitions to measure the elastic modulus of spongy materials, especially polyvinyl alcohol (PVA) sponge. However, there is no agreement as to which stress-strain definition should be implemented. This study was aimed to show how different results are given by the various definitions of stress-strain used, and to recommend a specific definition when testing spongy materials. A fabricated PVA sponge was subjected to a series of tensile tests in order to measure its mechanical properties. Three stress definitions (second Piola-Kichhoff stress, engineering stress, and true stress) and four strain definitions (Almansi-Hamel strain, Green-St. Venant strain, engineering strain, and true strain) were used to determine the elastic modulus. The results revealed that the Almansi-Hamel strain definition exhibited the highest non-linear stress-strain relation and, as a result, may overestimate the elastic modulus at different stress definitions (second Piola-Kichhoff stress, engineering stress, and true stress). The Green-St. Venant strain definition failed to address the non-linear stress-strain relation using different definitions of stress and invoked an underestimation of the elastic modulus values. Engineering stress and strain definitions were only valid for small strains and displacements, which make them impractical when analyzing spongy materials. The results showed that the effect of varying the stress definition on the maximum stress measurements was significant but not when calculating the elastic modulus. It is important to consider which stress-strain definition is employed when characterizing the mechanical properties of spongy materials. Although the true stress-true strain definition exhibits a non-linear relation, we favor it in spongy materials mechanics as it gives more accurate measurements of the material's response using the instantaneous values.

  17. Methods for predicting isochronous stress-strain curves

    International Nuclear Information System (INIS)

    Kiyoshige, Masanori; Shimizu, Shigeki; Satoh, Keisuke.

    1976-01-01

    Isochronous stress-strain curves show the relation between stress and total strain at a certain temperature with time as a parameter, and they are drawn up from the creep test results at various stress levels at a definite temperature. The concept regarding the isochronous stress-strain curves was proposed by McVetty in 1930s, and has been used for the design of aero-engines. Recently the high temperature characteristics of materials are shown as the isochronous stress-strain curves in the design guide for the nuclear energy equipments and structures used in high temperature creep region. It is prescribed that these curves are used as the criteria for determining design stress intensity or the data for analyzing the superposed effects of creep and fatigue. In case of the isochronous stress-strain curves used for the design of nuclear energy equipments with very long service life, it is impractical to determine the curves directly from the results of long time creep test, accordingly the method of predicting long time stress-strain curves from short time creep test results must be established. The method proposed by the authors, for which the creep constitution equations taking the first and second creep stages into account are used, and the method using Larson-Miller parameter were studied, and it was found that both methods were reliable for the prediction. (Kako, I.)

  18. A NURBS approximation of experimental stress-strain curves

    International Nuclear Information System (INIS)

    Fedorov, Timofey V.; Morrev, Pavel G.

    2016-01-01

    A compact universal representation of monotonic experimental stress-strain curves of metals and alloys is proposed. It is based on the nonuniform rational Bezier splines (NURBS) of second order and may be used in a computer library of materials. Only six parameters per curve are needed; this is equivalent to a specification of only three points in a stress-strain plane. NURBS-functions of higher order prove to be surplus. Explicit expressions for both yield stress and hardening modulus are given. Two types of curves are considered: at a finite interval of strain and at infinite one. A broad class of metals and alloys of various chemical compositions subjected to various types of preliminary thermo-mechanical working is selected from a comprehensive data base in order to test the methodology proposed. The results demonstrate excellent correspondence to the experimental data. Keywords: work hardening, stress-strain curve, spline approximation, nonuniform rational B-spline, NURBS.

  19. Probabilistic analysis of structures involving random stress-strain behavior

    Science.gov (United States)

    Millwater, H. R.; Thacker, B. H.; Harren, S. V.

    1991-01-01

    The present methodology for analysis of structures with random stress strain behavior characterizes the uniaxial stress-strain curve in terms of (1) elastic modulus, (2) engineering stress at initial yield, (3) initial plastic-hardening slope, (4) engineering stress at point of ultimate load, and (5) engineering strain at point of ultimate load. The methodology is incorporated into the Numerical Evaluation of Stochastic Structures Under Stress code for probabilistic structural analysis. The illustrative problem of a thick cylinder under internal pressure, where both the internal pressure and the stress-strain curve are random, is addressed by means of the code. The response value is the cumulative distribution function of the equivalent plastic strain at the inner radius.

  20. Thermodynamical aspects of modeling the mechanical response of granular materials

    International Nuclear Information System (INIS)

    Elata, D.

    1995-01-01

    In many applications in rock physics, the material is treated as a continuum. By supplementing the related conservation laws with constitutive equations such as stress-strain relations, a well-posed problem can be formulated and solved. The stress-strain relations may be based on a combination of experimental data and a phenomenological or micromechanical model. If the model is physically sound and its parameters have a physical meaning, it can serve to predict the stress response of the material to unmeasured deformations, predict the stress response of other materials, and perhaps predict other categories of the mechanical response such as failure, permeability, and conductivity. However, it is essential that the model be consistent with all conservation laws and consistent with the second law of thermodynamics. Specifically, some models of the mechanical response of granular materials proposed in literature, are based on intergranular contact force-displacement laws that violate the second law of thermodynamics by permitting energy generation at no cost. This diminishes the usefulness of these models as it invalidates their predictive capabilities. [This work was performed under the auspices of the U.S. DOE by Lawrence Livermore National Laboratory under Contract No. W-7405-ENG-48.

  1. Cyclic stress-strain behaviour under thermomechanical fatigue conditions - Modeling by means of an enhanced multi-component model

    Energy Technology Data Exchange (ETDEWEB)

    Christ, H J [Institut fuer Werkstofftechnik, Universitaet Siegen, D-57068 Siegen (Germany); Bauer, V, E-mail: hans-juergen.christ@uni-siegen.d [Wieland Werke AG, Graf-Arco Str. 36, D-89072 Ulm (Germany)

    2010-07-01

    The cyclic stress-strain behaviour of metals and alloys in cyclic saturation can reasonably be described by means of simple multi-component models, such as the model based on a parallel arrangement of elastic-perfectly plastic elements, which was originally proposed by Masing already in 1923. This model concept was applied to thermomechanical fatigue loading of two metallic engineering materials which were found to be rather oppositional with respect to cyclic plastic deformation. One material is an austenitic stainless steel of type AISI304L which shows dynamic strain aging (DSA) and serves as an example for a rather ductile alloy. A dislocation arrangement was found after TMF testing deviating characteristically from the corresponding isothermal microstructures. The second material is a third-generation near-gamma TiAl alloy which is characterized by a very pronounced ductile-to-brittle transition (DBT) within the temperature range of TMF cycling. Isothermal fatigue testing at temperatures below the DBT temperature leads to cyclic hardening, while cyclic softening was found to occur above DBT. The combined effect under TMF leads to a continuously developing mean stress. The experimental observations regarding isothermal and non-isothermal stress-strain behaviour and the correlation to the underlying microstructural processes was used to further develop the TMF multi-composite model in order to accurately predict the TMF stress-strain response by taking the alloy-specific features into account.

  2. Modeling Stress Strain Relationships and Predicting Failure Probabilities For Graphite Core Components

    Energy Technology Data Exchange (ETDEWEB)

    Duffy, Stephen [Cleveland State Univ., Cleveland, OH (United States)

    2013-09-09

    This project will implement inelastic constitutive models that will yield the requisite stress-strain information necessary for graphite component design. Accurate knowledge of stress states (both elastic and inelastic) is required to assess how close a nuclear core component is to failure. Strain states are needed to assess deformations in order to ascertain serviceability issues relating to failure, e.g., whether too much shrinkage has taken place for the core to function properly. Failure probabilities, as opposed to safety factors, are required in order to capture the bariability in failure strength in tensile regimes. The current stress state is used to predict the probability of failure. Stochastic failure models will be developed that can accommodate possible material anisotropy. This work will also model material damage (i.e., degradation of mechanical properties) due to radiation exposure. The team will design tools for components fabricated from nuclear graphite. These tools must readily interact with finite element software--in particular, COMSOL, the software algorithm currently being utilized by the Idaho National Laboratory. For the eleastic response of graphite, the team will adopt anisotropic stress-strain relationships available in COMSO. Data from the literature will be utilized to characterize the appropriate elastic material constants.

  3. Modeling Stress Strain Relationships and Predicting Failure Probabilities For Graphite Core Components

    International Nuclear Information System (INIS)

    Duffy, Stephen

    2013-01-01

    This project will implement inelastic constitutive models that will yield the requisite stress-strain information necessary for graphite component design. Accurate knowledge of stress states (both elastic and inelastic) is required to assess how close a nuclear core component is to failure. Strain states are needed to assess deformations in order to ascertain serviceability issues relating to failure, e.g., whether too much shrinkage has taken place for the core to function properly. Failure probabilities, as opposed to safety factors, are required in order to capture the bariability in failure strength in tensile regimes. The current stress state is used to predict the probability of failure. Stochastic failure models will be developed that can accommodate possible material anisotropy. This work will also model material damage (i.e., degradation of mechanical properties) due to radiation exposure. The team will design tools for components fabricated from nuclear graphite. These tools must readily interact with finite element software--in particular, COMSOL, the software algorithm currently being utilized by the Idaho National Laboratory. For the eleastic response of graphite, the team will adopt anisotropic stress-strain relationships available in COMSO. Data from the literature will be utilized to characterize the appropriate elastic material constants.

  4. Superelastic stress-strain behavior in ferrogels with different types of magneto-elastic coupling

    Science.gov (United States)

    Cremer, Peet; Löwen, Hartmut; Menzel, Andreas M.

    Colloidal magnetic particles embedded in an elastic polymer matrix constitute a smart material called ferrogel. It responds to an applied external magnetic field by changes in elastic properties, which can be exploited for various applications like dampers, vibration absorbers, or actuators. Under appropriate conditions, the stress-strain behavior of a ferrogel can display a fascinating feature: superelasticity, the capability to reversibly deform by a huge amount while barely altering the applied load. In a previous work, using numerical simulations, we investigated this behavior assuming that the magnetic moments carried by the embedded particles can freely reorient to minimize their magnetic interaction energy. Here, we extend the analysis to ferrogels where restoring torques by the surrounding matrix hinder rotations towards a magnetically favored configuration. For example, the particles can be chemically cross-linked into the polymer matrix and the magnetic moments can be fixed to the particle axes. We demonstrate that these systems still feature a superelastic regime. As before, the nonlinear stress-strain behavior can be reversibly tailored during operation by external magnetic fields. Yet, the different coupling of the magnetic moments causes different types of response to external stimuli. For instance, an external magnetic field applied parallel to the stretching axis hardly affects the superelastic regime but stiffens the system beyond it. Other smart materials featuring superelasticity, e.g. metallic shape-memory alloys, have already found widespread applications. Our soft polymer systems offer many additional advantages like a typically higher deformability and enhanced biocompatibility combined with high tunability.

  5. Biological Responses to Materials

    Science.gov (United States)

    Anderson, James M.

    2001-08-01

    All materials intended for application in humans as biomaterials, medical devices, or prostheses undergo tissue responses when implanted into living tissue. This review first describes fundamental aspects of tissue responses to materials, which are commonly described as the tissue response continuum. These actions involve fundamental aspects of tissue responses including injury, inflammatory and wound healing responses, foreign body reactions, and fibrous encapsulation of the biomaterial, medical device, or prosthesis. The second part of this review describes the in vivo evaluation of tissue responses to biomaterials, medical devices, and prostheses to determine intended performance characteristics and safety or biocompatibility considerations. While fundamental aspects of tissue responses to materials are important from research and development perspectives, the in vivo evaluation of tissue responses to these materials is important for performance, safety, and regulatory reasons.

  6. Assessment of stress-strain data suitable for finite-element elastic--plastic analysis of shipping containers

    International Nuclear Information System (INIS)

    Rack, H.J.; Knorovsky, G.A.

    1978-09-01

    Stress-strain data which describes the influence of strain rate and temperature on the mechanical response of materials presently being used for light water reactor fuel shipping containers have been assembled. Selection of data has been limited to that which is suitable for use in finite-element elastic--plastic analysis of shipping containers (e.g., they must include complete material history profiles). Based on this information, recommendations have been made for further work which is required to complete the necessary data base

  7. Mimicking biological stress-strain behaviour with synthetic elastomers

    Science.gov (United States)

    Vatankhah-Varnosfaderani, Mohammad; Daniel, William F. M.; Everhart, Matthew H.; Pandya, Ashish A.; Liang, Heyi; Matyjaszewski, Krzysztof; Dobrynin, Andrey V.; Sheiko, Sergei S.

    2017-09-01

    Despite the versatility of synthetic chemistry, certain combinations of mechanical softness, strength, and toughness can be difficult to achieve in a single material. These combinations are, however, commonplace in biological tissues, and are therefore needed for applications such as medical implants, tissue engineering, soft robotics, and wearable electronics. Present materials synthesis strategies are predominantly Edisonian, involving the empirical mixing of assorted monomers, crosslinking schemes, and occluded swelling agents, but this approach yields limited property control. Here we present a general strategy for mimicking the mechanical behaviour of biological materials by precisely encoding their stress-strain curves in solvent-free brush- and comb-like polymer networks (elastomers). The code consists of three independent architectural parameters—network strand length, side-chain length and grafting density. Using prototypical poly(dimethylsiloxane) elastomers, we illustrate how this parametric triplet enables the replication of the strain-stiffening characteristics of jellyfish, lung, and arterial tissues.

  8. Material Response Characterization

    Science.gov (United States)

    1977-08-01

    models fit to vertical UX and TX data and a mean stress tension cutoff criterion. Because tests on the Kayenta sands one materials had revealed a definite...parameters. 9 This data characterizing the anisotropic response of the upper 30 feet of Kayenta material should not just be filed away; it should be used...9. Johnson, J. N., et al, "Anisotropic Mechanical Properties of Kayenta Sandstone (MIXED COMPANY Site) for Ground Motion Calculations," Terra Tek TR

  9. Stress strain tensors with their application to x-ray stress measurement

    International Nuclear Information System (INIS)

    Kurita, Masanori

    2015-01-01

    This paper describes in detail the method of obtaining the formulas of stress-strain tensor that express the directional dependence of stress-strain, that is, how these values change in response to coordinate transformation, and clarifies the preconditions for supporting both formulas. The two conversion formulas are both the second order of tensor, and the formula of strain tensor not only does not use the relational expression of stress and strain at all, but also is obtained completely independently of the formula of stress tensor. Except for the condition that the strain is very small (elastic deformation) in the conversion formula of strain, both formulas unconditionally come into effect. In other words, both formulas hold true even in the isotropic elastic body or anisotropic elastic body. It was shown that the conversion formula of strain can be derived from the conversion formula of stress using the formula of Hooke for isotropic elastic body. From these three-dimensional expressions, the two-dimensional stress-strain coordinate conversion formula that is used for Mohr's stress-strain circle was derived. It was shown that these formulas hold true for three-dimensional stress condition with stress-strain components in the three-axial direction that are not plane stress nor plane strain condition. In addition, as an application case of this theory, two-dimensional and three-dimensional X-ray stress measurements that are effective for residual stress measurement were shown. (A.O.)

  10. Investigation of isochronous stress-strain formulations for elevated temperature structural design

    International Nuclear Information System (INIS)

    Koo, Gyeong Hoi; Kim, Jong Bum

    2012-01-01

    For elevated temperature design evaluations by the ASME-NH rules, the most important material data is the isochronous stress-strain curves, which can provide design creep information. The main purpose of this paper is to investigate appropriate formulations to be able to generate the isochronous stress-strain curves and implement it to the computer program which is coded the ASME-NH design evaluation procedures. To do this, formulations by the strain-time relationship are investigated in detail and the sensitivity studies for rapid initial transient creep contributions, slower and longer transient creep contribution, and secondary creep contributions are carried out for type 316 austenitic stainless steel. From the results of this study, it is found that the strain-time relationship formulations can well describe the isochronous stress-strain curves with the transient creep contributions

  11. Numerical analysis oriented biaxial stress-strain relation and failure criterion of plain concrete

    International Nuclear Information System (INIS)

    Link, J.

    1975-01-01

    A biaxial stress-strain relation and failure criterion is proposed, which is applicable to structural analysis methods. The formulation of material behavior of plain concrete in biaxial stress-state was developed. A nonlinear elastic, anisotropic stress-strain relation was derived with two moduli of elasticity, E 1 , E 2 and Poisson's ratios, ν 1 , ν 2 , which depend on the prevailing biaxial stress state. The stress-strain relation is valid in the whole biaxial stress field, that means with a smooth transition between the domains of tension/tension, tension/compression and compression/compression. The stress-dependent moduli E 1 , E 2 and the Poisson's ratios ν 1 , ν 2 are approximated by polynomials, trigonometrical and exponential functions. A failure criterion was defined by approximating the test results of the biaxial ultimate concrete strength with a 7th degree polynomial, which is also valid in the whole biaxial stress domain. The definition of the state of failure is given as a function of stresses as well as strains. Initial parameters of the formulation of the biaxial material behavior are the uniaxial cylindrical strength of concrete and the initial values of Young's modulus and Poisson's ratio. A simple expansion of this formulation makes it applicable not only to normal but also to light-weight concrete. Comparison of numerically calculated stress-strain curves up to the ultimate biaxial stresses which indicate the failure criteria with those obtained from tests show a very good agreement. It is shown, that the biaxial stress-strain relation can be extended for use in cases of triaxial tension/tension/compression stress state. Numerical examples of analysis of concrete slabs show the importance of incorporation of a realistic material behavior for better safety estimations

  12. Correction of the post -- necking true stress -- strain data using instrumented nanoindentation

    Science.gov (United States)

    Romero Fonseca, Ivan Dario

    The study of large plastic deformations has been the focus of numerous studies particularly in the metal forming processes and fracture mechanics fields. A good understanding of the plastic flow properties of metallic alloys and the true stresses and true strains induced during plastic deformation is crucial to optimize the aforementioned processes, and to predict ductile failure in fracture mechanics analyzes. Knowledge of stresses and strains is extracted from the true stress-strain curve of the material from the uniaxial tensile test. In addition, stress triaxiality is manifested by the neck developed during the last stage of a tensile test performed on a ductile material. This necking phenomenon is the factor responsible for deviating from uniaxial state into a triaxial one, then, providing an inaccurate description of the material's behavior after the onset of necking. The research of this dissertation is aimed at the development of a correction method for the nonuniform plastic deformation (post-necking) portion of the true stress-strain curve. The correction proposed is based on the well-known relationship between hardness and flow (yield) stress, except that instrumented nanoindentation hardness is utilized rather than conventional macro or micro hardness. Three metals with different combinations of strain hardening behavior and crystal structure were subjected to quasi-static tensile tests: power-law strain hardening low carbon G10180 steel (BCC) and electrolytic tough pitch copper C11000 (FCC), and linear strain hardening austenitic stainless steel S30400 (FCC). Nanoindentation hardness values, measured on the broken tensile specimen, were converted into flow stress values by means of the constraint factor C from Tabor's, the representative plastic strainepsilonr and the post-test true plastic strains measured. Micro Vickers hardness testing was carried out on the sample as well. The constraint factors were 5.5, 4.5 and 4.5 and the representative plastic

  13. Analysis of stress-strain relationships in silicon ribbon

    Science.gov (United States)

    Dillon, O. W., Jr.

    1984-01-01

    An analysis of stress-strain relationships in silicon ribbon is presented. A model to present entire process, dynamical Transit Analysis is developed. It is found that knowledge of past-strain history is significant in modeling activities.

  14. Determination of Stress-Strain Characteristics of Railhead Steel using Image Analysis

    OpenAIRE

    Bandula-Heva; T.; Dhanasekar; M.

    2011-01-01

    True stress-strain curve of railhead steel is required to investigate the behaviour of railhead under wheel loading through elasto-plastic Finite Element (FE) analysis. To reduce the rate of wear, the railhead material is hardened through annealing and quenching. The Australian standard rail sections are not fully hardened and hence suffer from non-uniform distribution of the material property; usage of average properties in the FE modelling can potentially induce error in the predic...

  15. Limitations of Hollomon and Ludwigson stress-strain relations in assessing the strain hardening parameters

    International Nuclear Information System (INIS)

    Samuel, K G

    2006-01-01

    It is shown that the deviation from the ideal Hollomon relation in describing the stress-strain behaviour is characteristic of all materials at low strains. The Ludwigson relation describing the deviation from the Hollomon relation at low strains is critically analysed and it is shown that the deviation at low strains is a consequence of some unknown 'plastic strain equivalent' present in the material. Stress strain curves obeying an ideal Hollomon relation as well as that of a structurally modified (prior cold worked) material were simulated and compared. The results show that the yield strength and the flow strength of a material at constant strain rate and temperature are dictated by the magnitude of the 'plastic strain equivalent' term. It is shown that this component need not necessarily mean a prior plastic strain present in the material due to prior cold work alone and that prior cold work strain will add to this. If this component is identified, the stress-strain behaviour can be adequately described by the Swift relation. It is shown that in both formalisms, the strain hardening index is a function of the yield strength of the material

  16. Analysis of Mechanical Stresses/Strains in Superconducting Wire

    Science.gov (United States)

    Barry, Matthew; Chen, Jingping; Zhai, Yuhu

    2016-10-01

    The optimization of superconducting magnet performance and development of high-field superconducting magnets will greatly impact the next generation of fusion devices. A successful magnet development, however, relies deeply on the understanding of superconducting materials. Among the numerous factors that impact a superconductor's performance, mechanical stress is the most important because of the extreme operation temperature and large electromagnetic forces. In this study, mechanical theory is used to calculate the stresses/strains in typical superconducting strands, which consist of a stabilizer, a barrier, a matrix and superconducting filaments. Both thermal loads and mechanical loads are included in the analysis to simulate operation conditions. Because this model simulates the typical architecture of major superconducting materials, such as Nb3Sn, MgB2, Bi-2212 etc., it provides a good overall picture for us to understand the behavior of these superconductors in terms of thermal and mechanical loads. This work was supported in part by the U.S. Department of Energy, Office of Science, Office of Workforce Development for Teachers and Scientists (WDTS) under the Science Undergraduate Laboratory Internship (SULI) program.

  17. An effective uniaxial tensile stress-strain relationship for prestressed concrete

    International Nuclear Information System (INIS)

    Chitnuyanondh, L.; Rizkalla, S.; Murray, D.W.; MacGregor, J.G.

    1979-02-01

    This report evaluates the direct tensile strength and an equivalent uniaxial tensile stress-strain relationship for prestressed concrete using data from specimens tested at the University of Alberta which represent segments from the wall of a containment vessel. The stress-strain relationship, when used in conjunction with the BOSOR5 program, enables prediction of the response of prestressed concrete under any biaxial combination of compressive and/or tensile stresses. Comparisons between the experimental and analytical (BOSOR5) load-strain response of the wall segments are also presented. It is concluded that the BOSOR5 program is able to predict satisfactorily the response of the wall segments and multi-layered shell structures. (author)

  18. The stress-strain relationship for multilayers of the high Tc superconducting oxides

    International Nuclear Information System (INIS)

    Hidaka, H.; Yamamura, H.

    1988-01-01

    This paper reports the calculation of the stress-strain relationship for multilayers of the high Tc superconducting oxides. The elucidation of this relationship is expected quite helpful for the preparation of high-quality multilayers of these materials. This calculation is possible to do in the same way of Timoshenko's bi-metal treatment. The authors did computation of the residual stress and strain, and the state of stress and strain for these multilayers has been acquired in detail by this calculation

  19. Stress, strain, and structural dynamics an interactive handbook of formulas, solutions, and Matlab toolboxes

    CERN Document Server

    Yang, Bingen

    2005-01-01

    Stress, Strain, and Structural Dynamics is a comprehensive and definitive reference to statics and dynamics of solids and structures, including mechanics of materials, structural mechanics, elasticity, rigid-body dynamics, vibrations, structural dynamics, and structural controls. This text integrates the development of fundamental theories, formulas and mathematical models with user-friendly interactive computer programs, written in the powerful and popular MATLAB. This unique merger of technical referencing and interactive computing allows instant solution of a variety of engineering problems

  20. Stress-strain curve of concretes with recycled concrete aggregates: analysis of the NBR 8522 methodology

    Directory of Open Access Journals (Sweden)

    D. A. GUJEL

    Full Text Available ABSTRACT This work analyses the methodology "A" (item A.4 employed by the Brazilian Standard ABNT 8522 (ABNT, 2008 for determining the stress-strain behavior of cylindrical specimens of concrete, presenting considerations about possible enhancements aiming it use for concretes with recycled aggregates with automatic test equipment. The methodology specified by the Brazilian Standard presents methodological issues that brings distortions in obtaining the stress-strain curve, as the use of a very limited number of sampling points and by inducing micro cracks and fluency in the elastic behavior of the material due to the use of steady stress levels in the test. The use of a base stress of 0.5 MPa is too low for modern high load test machines designed do high strength concrete test. The work presents a discussion over these subjects, and a proposal of a modified test procedure to avoid such situations.

  1. The Cyclic Stress-Strain Curve of Polycrystals

    DEFF Research Database (Denmark)

    Pedersen, Ole Bøcker; Rasmussen, K. V.; Winter, A. T.

    1982-01-01

    The internal stresses implied by the Sachs model are estimated for individual PSBs at low plastic strain amplitudes and for homogeneously sheared grains at higher plastic strain amplitudes. The analysis shows that the Sachs model can account semi-quantitatively for experimentally measured cyclic...... stress-strain curves for copper. A similar approximative analysis of the Taylor model cannot account for the data. An interesting feature of the Sachs model is that, although it is assumed that the flow condition is entirely controlled by the PSBs. the predicted cyclic stress-strain curve displays...

  2. Computer modeling of the stress-strain state of welded construction

    Science.gov (United States)

    Nurguzhin, Marat; Danenova, Gulmira; Akhmetzhanov, Talgat

    2017-11-01

    At the present time the maintenance of the welded construction serviceability over normative service life is provided by the maintenance system on the basis of the guiding documents according to the concept of "fail safe". However, technology factors relating to welding such as high residual stresses and significant plastic strains are not considered in the guiding documents. The design procedure of the stressed-strained state of welded constructions is suggested in the paper. The procedure investigates welded constructions during welding and the external load using the program ANSYS. In this paper, the model of influence of the residual stress strain state on the factor of stress intensity is proposed. The calculation method of the residual stressed-strained state (SSS) taking into account the phase transition is developed by the authors. Melting and hardening of a plate material during heating and cooling is considered. The thermomechanical problem of heating a plate by a stationary heat source is solved. The setup of the heating spot center on distance (190 mm) from the crack top in a direction of its propagation leads to the fact that the value of total factor of stress intensity will considerably decrease under action of the specified residual compressing stresses. It can lower the speed of the crack propagation to zero. The suggested method of survivability maintenance can be applied during operation with the purpose of increasing the service life of metal constructions up to running repair of technological machines.

  3. Measurement of the uniaxial mechanical properties of rat skin using different stress-strain definitions.

    Science.gov (United States)

    Karimi, A; Navidbakhsh, M

    2015-05-01

    The mechanical properties of skin tissue may vary according to the anatomical locations of a body. There are different stress-strain definitions to measure the mechanical properties of skin tissue. However, there is no agreement as to which stress-strain definition should be implemented to measure the mechanical properties of skin at different anatomical locations. Three stress definitions (second Piola-Kichhoff stress, engineering stress, and true stress) and four strain definitions (Almansi-Hamel strain, Green-St. Venant strain, engineering strain, and true strain) are employed to determine the mechanical properties of skin tissue at back and abdomen locations of a rat body. The back and abdomen skins of eight rats are excised and subjected to a series of tensile tests. The elastic modulus, maximum stress, and strain of skin tissues are measured using three stress definitions and four strain definitions. The results show that the effect of varying the stress definition on the maximum stress measurements of the back skin is significant but not when calculating the elastic modulus and maximum strain. No significant effects are observed on the elastic modulus, maximum stress, and strain measurements of abdomen skin by varying the stress definition. In the true stress-strain diagram, the maximum stress (20%), and elastic modulus (35%) of back skin are significantly higher than that of abdomen skin. The true stress-strain definition is favored to measure the mechanical properties of skin tissue since it gives more accurate measurements of the skin's response using the instantaneous values. © 2014 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

  4. Stress-strain relationship of high-strength steel (HSS) reinforcing bars

    Science.gov (United States)

    Anggraini, Retno; Tavio, Raka, I. Gede Putu; Agustiar

    2018-05-01

    The introduction of High-Strength Steel (HSS) reinforcing bars in reinforced concrete members has gained much attention in recent years and led to many advantages such as construction timesaving. It is also more economical since it can reduce the amount of reinforcing steel bars used in concrete members which in turn alleviates the congestion of reinforcement. Up to present, the building codes, e.g. American Concrete Institute (ACI) 318M-14 and Standard National Indonesia (SNI) 2847:2013, still restrict the use of higher-strength steel reinforcing bars for concrete design up to Grade 420 MPa due to the possible suspected brittle behavior of concrete members. This paper evaluates the characteristics of stress-strain relationships of HSS bars if they are comparable to the characteristics of those of Grade 420 MPa. To achieve the objective of the study, a series of steel bars from various grades (420, 550, 650, and 700 MPa) was selected. Tensile tests of these steel samples were conducted under displacement-controlled mode to capture the complete stress-strain curves and particularly the post-yield response of the steel bars. The results indicate that all the steel bars tested had the actual yield strengths greater than the corresponding specified values. The stress-strain curves of HSS reinforcing bars (Grade 550, 650, and 700 MPa) performed slightly different characteristics with those of Grade 420 MPa.

  5. An experimental study on the mechanical properties of rat brain tissue using different stress-strain definitions.

    Science.gov (United States)

    Karimi, Alireza; Navidbakhsh, Mahdi

    2014-07-01

    There are different stress-strain definitions to measure the mechanical properties of the brain tissue. However, there is no agreement as to which stress-strain definition should be employed to measure the mechanical properties of the brain tissue at both the longitudinal and circumferential directions. It is worth knowing that an optimize stress-strain definition of the brain tissue at different loading directions may have implications for neuronavigation and surgery simulation through haptic devices. This study is aimed to conduct a comparative study on different results are given by the various definitions of stress-strain and to recommend a specific definition when testing brain tissues. Prepared cylindrical samples are excised from the parietal lobes of rats' brains and experimentally tested by applying load on both the longitudinal and circumferential directions. Three stress definitions (second Piola-Kichhoff stress, engineering stress, and true stress) and four strain definitions (Almansi-Hamel strain, Green-St. Venant strain, engineering strain, and true strain) are used to determine the elastic modulus, maximum stress and strain. The highest non-linear stress-strain relation is observed for the Almansi-Hamel strain definition and it may overestimate the elastic modulus at different stress definitions at both the longitudinal and circumferential directions. The Green-St. Venant strain definition fails to address the non-linear stress-strain relation using different definitions of stress and triggers an underestimation of the elastic modulus. The results suggest the application of the true stress-true strain definition for characterization of the brain tissues mechanics since it gives more accurate measurements of the tissue's response using the instantaneous values.

  6. Stress-Strain Relationship of Synthetic Fiber Reinforced Concrete Columns

    Directory of Open Access Journals (Sweden)

    Rosidawani

    2017-01-01

    Full Text Available Many empirical confinement models for normal and high strength concrete have been developed. Nevertheless, reported studies in the term of confinement of fiber reinforced concrete are limited. Whereas, the use of fiber reinforced concrete in structural elements has become the subject of the research and has indicated positive experiences. Since the stress-strain relationship of concrete in compression is required for analysis of structural members, the study of the stress-strain relationship for synthetic fiber reinforced concrete is substantial. The aim of the study is to examine the capabilities of the various models available in the literature to predict the actual experimental behavior of synthetic fiber reinforced high-strength concrete columns. The experimental data used are the results of the circular column specimens with the spiral spacing and the volume fraction of synthetic fiber as the test variables. The axial stress-strain curves from the tests are then compared with the various models of confinement from the literature. The performance index of each model is measured by using the coefficient of variation (COV concept of stress and strain behavior parameter. Among the confinement models, Cusson model shows the closest valid value of the coefficient of variation.

  7. Stress-strain properties of railway steel at strain rates of upto 105 per second

    International Nuclear Information System (INIS)

    Hashmi, M.S.J.; Islam, M.N.

    1985-01-01

    This paper presents the stress-strain characteristics of railway steel at strain rates of up to 10 5 /s at room temperature determined by a new technique. In determining the results, account has been taken of the strain-rate variation, the total strain and the strain rate history. The effect of friction, material inertia and temperature rise is also assessed and an empirical constitutive equation describing the strain-rate and strain sensitive flow stress for this type of steel is proposed. (orig.)

  8. Nuclear Energy Enabling Technologies (NEET) Reactor Materials: News for the Reactor Materials Crosscut, May 2016

    Energy Technology Data Exchange (ETDEWEB)

    Maloy, Stuart Andrew [Los Alamos National Lab. (LANL), Los Alamos, NM (United States). Materials Science in Radiation and Dynamics Extremes

    2016-09-26

    In this newsletter for Nuclear Energy Enabling Technologies (NEET) Reactor Materials, pages 1-3 cover highlights from the DOE-NE (Nuclear Energy) programs, pages 4-6 cover determining the stress-strain response of ion-irradiated metallic materials via spherical nanoindentation, and pages 7-8 cover theoretical approaches to understanding long-term materials behavior in light water reactors.

  9. Experimental determination of the micro-scale strength and stress-strain relation of an epoxy resin

    DEFF Research Database (Denmark)

    Zike, Sanita; Sørensen, Bent F.; Mikkelsen, Lars Pilgaard

    2016-01-01

    An approach is developed for determining the stress-strain law and a failure stress appropriate for micro-mechanical models of polymer materials. Double cantilever beam test specimens, made of an epoxy polymer with notches having finite root radius, were subjected to pure bending moments in an en......An approach is developed for determining the stress-strain law and a failure stress appropriate for micro-mechanical models of polymer materials. Double cantilever beam test specimens, made of an epoxy polymer with notches having finite root radius, were subjected to pure bending moments......-scale (5–6%). The hardening exponent of a power law hardening material was obtained by the use of the J-integral, estimating the strain energy density around the notch. The hardening exponent was found to be within the range of 5–6 and the corresponding micro-scale failure stress was in the range of 220...

  10. Frequency Response of Synthetic Vocal Fold Models with Linear and Nonlinear Material Properties

    Science.gov (United States)

    Shaw, Stephanie M.; Thomson, Scott L.; Dromey, Christopher; Smith, Simeon

    2012-01-01

    Purpose: The purpose of this study was to create synthetic vocal fold models with nonlinear stress-strain properties and to investigate the effect of linear versus nonlinear material properties on fundamental frequency (F[subscript 0]) during anterior-posterior stretching. Method: Three materially linear and 3 materially nonlinear models were…

  11. STRESS - STRAIN CURVE ANALYSIS OF WOVEN FABRICS MAD E FROM COMBED YARNS TYPE WOOL

    Directory of Open Access Journals (Sweden)

    VÎLCU Adrian

    2014-05-01

    Full Text Available The paper analyses the tensile behavior of woven fabrics made from 45%Wool + 55% PES used for garments. Analysis of fabric behavior during wearing has shown that these are submitted to simple and repeated uni-axial or bi-axial tensile strains. The level of these strains is often within the elastic limit, rarely going over yielding. Therefore the designer must be able to evaluate the mechanical behavior of such fabrics in order to control the fabric behavior in the garment. This evaluation is carried out based on the tensile testing, using certain indexes specific to the stress-strain curve. The paper considers an experimental matrix based on woven fabrics of different yarn counts, different or equal yarn count for warp and weft systems and different structures. The fabrics were tested using a testing machine and the results were then compared in order to determine the fabrics’ tensile behavior and the factors of influence that affect it.From the point of view of tensile testing, the woven materials having twill weave are preferable because this type of structure is characterized by higher durability and better yarn stability in the fabric. In practice, the woven material must exhibit an optimum behavior to repeated strains, flexions and abrasions during wearing process. The analysis of fabrics tensile properties studied by investigation of stress-strain diagrams reveals that the main factors influencing the tensile strength are: yarns fineness, technological density of those two systems of yarns and the weaving type.

  12. Stress strain flow curves for Cu-OFP

    International Nuclear Information System (INIS)

    Sandstroem, Rolf; Hallgren, Josefin

    2009-04-01

    Stress strain curves of oxygen free copper alloyed with phosphorus Cu-OFP have been determined in compression and tension. The compression tests were performed at room temperature for strain rates between 10 -5 and 10 -3 1/s. The tests in tension covered the temperature range 20 to 175 deg C for strain rates between 10 -7 and 5x10 -3 1/s. The results in compression and tension were close for similar strain rates. A model for stress strain curves has been formulated using basic dislocation mechanisms. The model has been set up in such a way that fitting of parameters to the curves is avoided. By using a fundamental creep model as a basis a direct relation to creep data has been established. The maximum engineering flow stress in tension is related to the creep stress giving the same strain rate. The model reproduces the measured flow curves as function of temperature and strain rate in the investigated interval. The model is suitable to use in finite-element computations of structures in Cu-OFP

  13. Micromechanical Model for Deformation in Solids with Universal Predictions for Stress-Strain Curves and Slip Avalanches

    International Nuclear Information System (INIS)

    Dahmen, Karin A.; Ben-Zion, Yehuda; Uhl, Jonathan T.

    2009-01-01

    A basic micromechanical model for deformation of solids with only one tuning parameter (weakening ε) is introduced. The model can reproduce observed stress-strain curves, acoustic emissions and related power spectra, event statistics, and geometrical properties of slip, with a continuous phase transition from brittle to ductile behavior. Exact universal predictions are extracted using mean field theory and renormalization group tools. The results agree with recent experimental observations and simulations of related models for dislocation dynamics, material damage, and earthquake statistics.

  14. Mechanical Response of Thermoelectric Materials

    Energy Technology Data Exchange (ETDEWEB)

    Wereszczak, Andrew A. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Case, Eldon D. [Michigan State Univ., East Lansing, MI (United States)

    2015-05-01

    A sufficient mechanical response of thermoelectric materials (TEMats) to structural loadings is a prerequisite to the exploitation of any candidate TEMat's thermoelectric efficiency. If a TEMat is mechanically damaged or cracks from service-induced stresses, then its thermal and electrical functions can be compromised or even cease. Semiconductor TEMats tend to be quite brittle and have a high coefficient of thermal expansion; therefore, they can be quite susceptible to mechanical failure when subjected to operational thermal gradients. Because of this, sufficient mechanical response (vis-a-vis, mechanical properties) of any candidate TEMat must be achieved and sustained in the context of the service-induced stress state to which it is subjected. This report provides an overview of the mechanical responses of state-of-the-art TEMats; discusses the relevant properties that are associated with those responses and their measurement; and describes important, nonequilibrium phenomena that further complicate their use in thermoelectric devices. For reference purposes, the report also includes several appendixes that list published data on elastic properties and strengths of a variety of TEMats.

  15. Soil Stress-Strain Behavior: Measurement, Modeling and Analysis

    CERN Document Server

    Ling, Hoe I; Leshchinsky, Dov; Koseki, Junichi; A Collection of Papers of the Geotechnical Symposium in Rome

    2007-01-01

    This book is an outgrowth of the proceedings for the Geotechnical Symposium in Roma, which was held on March 16 and 17, 2006 in Rome, Italy. The Symposium was organized to celebrate the 60th birthday of Prof. Tatsuoka as well as honoring his research achievement. The publications are focused on the recent developments in the stress-strain behavior of geomaterials, with an emphasis on laboratory measurements, soil constitutive modeling and behavior of soil structures (such as reinforced soils, piles and slopes). The latest advancement in the field, such as the rate effect and dynamic behavior of both clay and sand, behavior of modified soils and soil mixtures, and soil liquefaction are addressed. A special keynote paper by Prof. Tatsuoka is included with three other keynote papers (presented by Prof. Lo Presti, Prof. Di Benedetto, and Prof. Shibuya).

  16. Measurement of stress strain and vibrational properties of tendons

    Science.gov (United States)

    Revel, Gian Marco; Scalise, Alessandro; Scalise, Lorenzo

    2003-08-01

    The authors present a new non-intrusive experimental procedure based on laser techniques for the measurement of mechanical properties of tendons. The procedure is based on the measurement of the first resonance frequency of the tendon by laser Doppler vibrometry during in vitro tensile experiments, with the final aim of establishing a measurement procedure to perform the mechanical characterization of tendons by extracting parameters such as the resonance frequency, also achievable during in vivo investigation. The experimental procedure is reported, taking into account the need to simulate the physiological conditions of the Achilles tendon, and the measurement technique used for the non-invasive determination of tendon cross-sectional area during tensile vibration tests at different load levels is described. The test procedure is based on a tensile machine, which measures longitudinal tendons undergoing controlled load conditions. Cross-sectional area is measured using a new non-contact procedure for the measurement of tendon perimeter (repeatability of 99% and accuracy of 2%). For each loading condition, vibration resonance frequency and damping, cross-sectional area and tensile force are measured, allowing thus a mechanical characterization of the tendon. Tendon stress-strain curves are reported. Stress-strain curves have been correlated to the first vibration resonance frequency and damping of the tendon measured using a single-point laser Doppler vibrometer. Moreover, experimental results have been compared with a theoretical model of a vibrating cord showing discrepancies. In vitro tests are reported, demonstrating the validity of the method for the comparison of different aged rabbit tendons.

  17. The role of creep in stress strain curves for copper

    International Nuclear Information System (INIS)

    Sandström, Rolf; Hallgren, Josefin

    2012-01-01

    Highlights: ► A dislocation based model takes into account both dynamic and static recovery. ► Tests at constant load and at constant strain rate modelled without fitting parameters. ► The model can describe primary and secondary creep of Cu-OFP from 75 to 250 °C. ► The temperature and strain rate dependence of stress strain curves can be modelled. ► Intended for the slow strain rates in canisters for storage of nuclear waste. - Abstract: A model for plastic deformation in pure copper taking work hardening, dynamic recovery and static recovery into account, has been formulated using basic dislocation mechanisms. The model is intended to be used in finite-element computations of the long term behaviour of structures in Cu-OFP for storage of nuclear waste. The relation between the strain rate and the maximum flow stress in the model has been demonstrated to correspond to strain rate versus stress in creep tests for oxygen free copper alloyed with phosphorus Cu-OFP. A further development of the model can also represent the primary and secondary stage of creep curves. The model is compared to stress strain curves in compression and tension for Cu-OFP. The compression tests were performed at room temperature for strain rates between 5 × 10 −5 and 5 × 10 −3 s −1 . The tests in tension covered the temperature range 20–175 °C for strain rates between 1 × 10 −7 and 1 × 10 −4 s −1 . Consequently, it is demonstrated that the model can represent mechanical test data that have been generated both at constant load and at constant strain rate without the use of any fitting parameters.

  18. Hazardous Materials Management and Emergency Response (HAMMER)

    Data.gov (United States)

    Federal Laboratory Consortium — The Volpentest Hazardous Materials Management and Emergency Response (HAMMER) Federal Training Center is a safety and emergency response training center that offers...

  19. Elasto-plastic stress/strain at notches, comparison of test and approximative computations

    International Nuclear Information System (INIS)

    Beste, A.; Seeger, T.

    1979-01-01

    The lifetime of cyclically loaded components is decisively determined by the value of the local load in the notch root. The determination of the elasto-plastic notch-stress and-strain is therefore an important element of recent methods of lifetime determination. These local loads are normally calculated with the help of approximation formulas. Yet there are no details about their accuracy. The basic construction of the approximation formulas is presented, along with some particulars. The use of approximations within the fully plastic range and for material laws which show a non-linear stress-strain (sigma-epsilon-)-behaviour from the beginning is explained. The use of approximation for cyclic loads is particularly discussed. Finally, the approximations are evaluated in terms of their exactness. The test results are compared with the results of the approximation calculations. (orig.) 891 RW/orig. 892 RKD [de

  20. Evaluation of stress-strain for characterization of the rheological behavior of alginate and carrageenan gels

    Directory of Open Access Journals (Sweden)

    E.J. Mammarella

    2002-12-01

    Full Text Available The stress-strain of samples deformed until failure and the relaxation response after 50% deformation of the initial height under constant stress were obtained. Uniaxial compression and stress-relaxation tests enabled satisfactory differentiation of the mechanical resistance of gels with different alginate and carrageenan concentrations. Higher values for initial force at the beginning of the relaxation test were associated with higher calcium uptake by the gels. An increment of failure stress during the uniaxial compression tests for higher concentration of calcium in the gel structure was also observed. The maximum amount of cation uptake was higher than the theoretical value for saturation of all the carboxylic groups available in alginate molecules due to structural rearrangements. Stress-relaxation tests indicated that the residual stress of the gel increased with kappa-carrageenan concentration.

  1. Modeling of stress-strain diagram on the basis of magnetic measurements

    International Nuclear Information System (INIS)

    Gorkunov, Eh.S.; Fedotov, V.P.; Bukhvalov, A.B.; Veselov, I.N.

    1997-01-01

    The model of a stress-strain diagram with taking into account the strain hardening and the growth of metal damageing is proposed. The model is applied to calculate a stress-strain curve for continuous cast 45 steel using the results of magnetic properties measuring. The latter permits predicting the durability of construction elements with the use of nondestructive magnetic testing

  2. A model for the stress-strain behavior of toughened polystyrene. Part 2

    NARCIS (Netherlands)

    Sjoerdsma, S.D.; Heikens, D.

    1982-01-01

    The general stress-strain relationship derived in an earlier paper is applied to analyse experimental stress-strain curves of polystyrene-polyethylene blends. It is concluded from the stress and temperature dependence of the rates of craze initiation and craze growth that these rates can be

  3. Stress/strain/time properties of highly compacted bentonite

    International Nuclear Information System (INIS)

    Pusch, R.

    1983-05-01

    In this paper, a recently developed creep theory based on statistical mechanics has been used to analyze a number of experimental creep curves, the conclusion being that the creep behavior of dense MX-80 bentonite is in agreement with the physical model, and that the average bond strength is within the hydrogen bond region. The latter conclusion thus indicates that interparticle displacements leading to macroscopic creep takes place in interparticle and intraparticle water lattices. These findings were taken as a justification to apply the creep theory to a prediction of the settlement over a one million year period. It gave an estimated settlement of 1 cm at maximum, which is of no practical significance. The thixotropic and viscous properties of highly compacted bentonite present certain difficulties in the determination and evaluation of the stress/strain/time parameters that are required for ordinary elastic and elasto-plastic analyses. Still, these parameters could be sufficiently well identified to allow for a preliminary estimation of the stresses induced in the metal canisters by slight rock displacements. The analysis, suggests that a 1 cm rapid shear perpendicular to the axes of the canisters can take place without harming them. (author)

  4. Micromechanical modelling of the cyclic stress-strain behaviour of nickel polycrystals

    International Nuclear Information System (INIS)

    Steckmeyer, A.; Sauzay, M.; Weidner, A.; Hieckmann, E.

    2012-01-01

    A crystalline elasto-plasticity model is proposed to describe the cyclic behaviour of face-centred cubic crystals. It is based on many experimental observations correlating the observed dislocation structures with the orientations of corresponding crystals. The model distinguishes between two families of crystals. The first family gathers crystals for which the tension-compression loading axis is located in the centre of the standard stereo-graphic triangle. These crystals, in which bundle and/or slip band dislocation structures are usually observed, are subjected to single slip deformation. The second family gathers crystals in which labyrinths or wall dislocation structures develop. These crystals are subjected to multiple slip deformation. Crystalline plasticity parameters are adjusted using only the single crystal cyclic stress strain curves measured for one orientation of each of the two families. The relevance of the model is evaluated through finite elements calculations of the uniaxial cyclic deformation of texture-free nickel polycrystals at room temperature. The macroscopic predictions are in reasonable agreement with experimental data concerning both the cyclic stress-strain curve and the hysteresis loops provided either large grain sizes or intermediate to high plastic strains are considered. By construction, the modelling is unable to predict grain size effect observed at low plastic strain. The distributions of the mean grain plastic strains become narrower as the macroscopic plastic strain amplitude increases, which appears consistent with the large scattering in high-cycle fatigue lifetimes usually observed. On the contrary, the distributions of mean grain axial stresses get broader, in agreement with neutron and X-ray diffraction measurement values published in the literature. The influence of the material parameters is then discussed. Finally, the cumulative probability curves of the number of cycles to fatigue microcrack nucleation are deduced

  5. Tensile Stress-Strain Results for 304L and 316L Stainless-Steel Plate at Temperature

    International Nuclear Information System (INIS)

    R. K. Blandford; D. K. Morton; S. D. Snow; T. E. Rahl

    2007-01-01

    The Idaho National Laboratory (INL) is conducting moderate strain rate (10 to 200 per second) research on stainless steel materials in support of the Department of Energy's (DOE) National Spent Nuclear Fuel Program (NSNFP). For this research, strain rate effects are characterized by comparison to quasi-static tensile test results. Considerable tensile testing has been conducted resulting in the generation of a large amount of basic material data expressed as engineering and true stress-strain curves. The purpose of this paper is to present the results of quasi-static tensile testing of 304/304L and 316/316L stainless steels in order to add to the existing data pool for these materials and make the data more readily available to other researchers, engineers, and interested parties. Standard tensile testing of round specimens in accordance with ASTM procedure A 370-03a were conducted on 304L and 316L stainless-steel plate materials at temperatures ranging from -20 F to 600 F. Two plate thicknesses, eight material heats, and both base and weld metal were tested. Material yield strength, Young's modulus, ultimate strength, ultimate strain, failure strength and failure strain were determined, engineering and true stress-strain curves to failure were developed, and comparisons to ASME Code minimums were made. The procedures used during testing and the typical results obtained are described in this paper

  6. Handbook for Response to Suspect Radioactive Materials

    International Nuclear Information System (INIS)

    Cliff, William C.; Pappas, Richard A.; Arthur, Richard J.

    2005-01-01

    This document provides response actions to be performed following the initial port, airport, or border crossing discovery of material that is suspected of being radioactive. The purpose of this guide is to provide actions appropriate for handling radioactive material

  7. Responsible stewardship of nuclear materials

    International Nuclear Information System (INIS)

    Hannum, W.H.

    1994-01-01

    The ability to tap the massive energy potential of nuclear fission was first developed as a weapon to end a terrible world war. Nuclear fission is also a virtually inexhaustible energy resource, and is the only energy supply in certain areas in Russia, Kazakhstan and elsewhere. The potential link between civilian and military applications has been and continues to be a source of concern. With the end of the Cold War, this issue has taken a dramatic turn. The U.S. and Russia have agreed to reduce their nuclear weapons stockpiles by as much as two-thirds. This will make some 100 tonnes of separated plutonium and 500 tonnes of highly enriched uranium available, in a form that is obviously directly usable for weapons. The total world inventory of plutonium is now around 1000 tonnes and is increasing at 60-70 tonnes per year. There is even more highly enriched uranium. Fortunately the correct answer to what to do with excess weapons material is also the most attractive. It should be used and reused as fuel for fast reactors. Material in use (particularly nuclear material) is very easy to monitor and control, and is quite unattractive for diversion. Active management of fissile materials not only makes a major contribution to economic stability and well-being, but also simplifies accountability, inspection and other safeguards processes; provides a revenue stream to pay for the necessary safeguards; and, most importantly, limits the prospective world inventory of plutonium to only that which is used and useful

  8. Multilinear stress-strain and failure calibrations for Ti-6Al-4V.

    Energy Technology Data Exchange (ETDEWEB)

    Corona, Edmundo [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)

    2018-02-01

    This memo concerns calibration of an elastic-plastic J2 material model for Ti-6Al-4V (grade 5) alloy based on tensile uniaxial stress-strain data obtained in the laboratory. In addition, tension tests on notched specimens provided data to calibrate two ductile failure models: Johnson-Cook and Wellman's tearing parameter. The tests were conducted by Kim Haulen- beek and Dave Johnson (1528) in the Structural Mechanics Laboratory (SML) during late March and early April, 2017. The SML EWP number was 4162. The stock material was a TIMETALR® 6-4 Titanium billet with 9 in. by 9 in. square section and length of 137 in. The product description indicates that it was a forging delivered in annealed condition (2 hours @ 1300oF, AC at the mill). The tensile mechanical properties reported in the material certi cation are given in Table 1, where σo represents the 0.2% strain offset yield stress, σu the ultimate stress, εf the elongation at failure and R.A. the reduction in area.

  9. Multiaxial Stress-Strain Modeling and Effect of Additional Hardening due to Nonproportional Loading

    International Nuclear Information System (INIS)

    Rashed, G.; Ghajar, R.; Farrahi, G.

    2007-01-01

    Most engineering components are subjected to multiaxial rather than uniaxial cyclic loading, which causes multiaxial fatigue. The pre-requisite to predict the fatigue life of such components is to determine the multiaxial stress strain relationship. In this paper the multiaxial cyclic stress-strain model under proportional loading is derived using the modified power law stress-strain relationship. The equivalent strain amplitude consisted of the normal strain excursion and maximum shear strain amplitude is used in the proportional model to include the additional hardening effect due to nonproportional loading. Therefore a new multiaxial cyclic stress-strain relationship is devised for out of phase nonproportional loading. The model is applied to the nonproportional loading case and the results are compared with the other researchers' experimental data published in the literature, which are in a reasonable agreement with the experimental data. The relationship presented here is convenient for the engineering applications

  10. Stimuli-responsive liquid crystalline materials

    NARCIS (Netherlands)

    Debije, M.G.; Schenning, A.P.H.J.; Hashmi, Saleem

    2016-01-01

    Stimuli-responsive materials which respond to triggers from the environment by changing their properties are one of the focal points in materials science. For precise functional properties, well-defined hierarchically ordered supramolecular materials are crucial. The self-assembly of liquid crystals

  11. Response to Illicit Trafficking of Radioactive Materials

    International Nuclear Information System (INIS)

    2010-01-01

    Two response paths are discussed in the presentation. Reactive response follows when an alarm of a border monitor goes off or a notification is received about an incident involving or suspected to involve radioactive materials. The response can also be the result of the finding of a discrepancy between a customs declaration form and the corresponding actual shipment. Proactive response is undertaken upon receipt of intelligence information suggesting the illicit trafficking of radioactive materials, notification about the discovery of non-compliance with transport regulations or if discrepancies are found in an inventory of radioactive materials.

  12. Study on elastic-plastic deformation analysis using a cyclic stress-strain curve

    International Nuclear Information System (INIS)

    Igari, Toshihide; Setoguchi, Katsuya; Yamauchi, Masafumi

    1983-01-01

    This paper presents the results of the elastic-plastic deformation analysis using a cyclic stress-strain curve with an intention to apply this method for predicting the low-cycle fatigue life. Uniaxial plastic cycling tests were performed on 2 1/4Cr-1Mo steel to investigate the correspondence between the cyclic stress-strain curve and the hysteresis loop, and also to determine what mathematical model should be used for analysis of deformation at stress reversal. Furthermore, a cyclic in-plane bending test was performed on a flat plate to clarify the validity of the cyclic stress-strain curve-based theoretical analysis. The results obtained are as follows: (1) The cyclic stress-strain curve corresponds nearly to the ascending curve of hysteresis loop scaled by a factor of 1/2 for both stress and strain. Therefore, the cyclic stress-strain curve can be determined from the shape of hysteresis loop, for simplicity. (2) To perform the elastic-plastic deformation analysis using the cyclic stress-strain curve is both practical and effective for predicting the cyclic elastic-plastic deformation of structures at the stage of advanced cycles. And Masing model can serve as a suitable mathematical model for such a deformation analysis. (author)

  13. Emergency Response to Radioactive Material Transport Accidents

    International Nuclear Information System (INIS)

    EL-shinawy, R.M.K.

    2009-01-01

    Although transport regulations issued by IAEA is providing a high degree of safety during transport opertions,transport accidents involving packages containing radioactive material have occurred and will occur at any time. Whenever a transport accident involving radioactive material accurs, and many will pose no radiation safety problems, emergency respnose actioms are meeded to ensure that radiation safety is maintained. In case of transport accident that result in a significant relesae of radioactive material , loss of shielding or loss of criticality control , that consequences should be controlled or mitigated by proper emergency response actions safety guide, Emergency Response Plamming and Prepardness for transport accidents involving radioactive material, was published by IAEA. This guide reflected all requirememts of IAEA, regulations for safe transport of radioactive material this guide provide guidance to the publicauthorites and other interested organziation who are responsible for establishing such emergency arrangements

  14. Hazardous materials transportation and emergency response programs

    International Nuclear Information System (INIS)

    Joy, D.S.; Fore, C.S.

    1983-01-01

    This presentation consists of the following visual aids; (1) detailed routing capabilities of truck, rail, barge; (2) legislative data base for hazardous materials; and (3) emergency response of accident site Eddyville, Kentucky (airports in vicinity of Eddyville, KY)

  15. Measurement of stress-strain behaviour of human hair fibres using optical techniques.

    Science.gov (United States)

    Lee, J; Kwon, H J

    2013-06-01

    Many studies have presented stress-strain relationship of human hair, but most of them have been based on an engineering stress-strain curve, which is not a true representation of stress-strain behaviour. In this study, a more accurate 'true' stress-strain curve of human hair was determined by applying optical techniques to the images of the hair deformed under tension. This was achieved by applying digital image cross-correlation (DIC) to 10× magnified images of hair fibres taken under increasing tension to estimate the strain increments. True strain was calculated by summation of the strain increments according to the theoretical definition of 'true' strain. The variation in diameter with the increase in longitudinal elongation was also measured from the 40× magnified images to estimate the Poisson's ratio and true stress. By combining the true strain and the true stress, a true stress-strain curve could be determined, which demonstrated much higher stress values than the conventional engineering stress-strain curve at the same degree of deformation. Four regions were identified in the true stress-strain relationship and empirical constitutive equations were proposed for each region. Theoretical analysis on the necking condition using the constitutive equations provided the insight into the failure mechanism of human hair. This analysis indicated that local thinning caused by necking does not occur in the hair fibres, but, rather, relatively uniform deformation takes place until final failure (fracture) eventually occurs. © 2012 Society of Cosmetic Scientists and the Société Française de Cosmétologie.

  16. Extremal Overall Elastic Response of Polycrystalline Materials

    DEFF Research Database (Denmark)

    Bendsøe, Martin P; Lipton, Robert

    1996-01-01

    Polycrystalline materials comprised of grains obtained froma single anisotropic material are considered in the frameworkof linear elasticity. No assumptions on the symmetry of thepolycrystal are made. We subject the material to independentexternal strain and stress fields with prescribed mean...... values.We show that the extremal overall elastic response is alwaysachieved by a configuration consisting of a single properlyoriented crystal. This result is compared to results for isotropicpolycrystals....

  17. Apparent stress-strain relationships in experimental equipment where magnetorheological fluids operate under compression mode

    International Nuclear Information System (INIS)

    Mazlan, S A; Ekreem, N B; Olabi, A G

    2008-01-01

    This paper presents an experimental investigation of two different magnetorheological (MR) fluids, namely, water-based and hydrocarbon-based MR fluids in compression mode under various applied currents. Finite element method magnetics was used to predict the magnetic field distribution inside the MR fluids generated by a coil. A test rig was constructed where the MR fluid was sandwiched between two flat surfaces. During the compression, the upper surface was moved towards the lower surface in a vertical direction. Stress-strain relationships were obtained for arrangements of equipment where each type of fluid was involved, using compression test equipment. The apparent compressive stress was found to be increased with the increase in magnetic field strength. In addition, the apparent compressive stress of the water-based MR fluid showed a response to the compressive strain of greater magnitude. However, during the compression process, the hydrocarbon-based MR fluid appeared to show a unique behaviour where an abrupt pressure drop was discovered in a region where the apparent compressive stress would be expected to increase steadily. The conclusion is drawn that the apparent compressive stress of MR fluids is influenced strongly by the nature of the carrier fluid and by the magnitude of the applied current

  18. Experimental Study of Stress-Strain Behaviour of Open-Cell Aluminium Foam Sandwich Panel for Automotive Structural Part

    Directory of Open Access Journals (Sweden)

    Nur Asmawiyah Ibrahim

    2017-07-01

    Full Text Available Because of high stiffness and strength to weight ratio, aluminium foam sandwich (AFS has huge advantage in automotive industries in order to reduce the vehicle’s weight which consequently will reduce the fuel consumption. While reducing the weight, AFS must also maintain high strength and durability compared to other competitive materials used which perform same functionalities. AFS had been proved its suitability for industrial application by previous researchers such as in aerospace, automotive and architecture. However, there is still a gap need to be filled in order to expand the use of the AFS in another application. In this paper, the tensile strength of AFS panel made of from aluminium skin sheets and open-cell aluminium foam core with various thickness is investigated. Design of experiment was developed according to JUMP (JMP statistical software and experimental work was done using universal testing machine. The stress-strain behavior was analysed. The result shows that the effect of skin to core ratio is significant on the stress-strain behavior.

  19. Neutrophil Responses to Sterile Implant Materials.

    Directory of Open Access Journals (Sweden)

    Siddharth Jhunjhunwala

    Full Text Available In vivo implantation of sterile materials and devices results in a foreign body immune response leading to fibrosis of implanted material. Neutrophils, one of the first immune cells to be recruited to implantation sites, have been suggested to contribute to the establishment of the inflammatory microenvironment that initiates the fibrotic response. However, the precise numbers and roles of neutrophils in response to implanted devices remains unclear. Using a mouse model of peritoneal microcapsule implantation, we show 30-500 fold increased neutrophil presence in the peritoneal exudates in response to implants. We demonstrate that these neutrophils secrete increased amounts of a variety of inflammatory cytokines and chemokines. Further, we observe that they participate in the foreign body response through the formation of neutrophil extracellular traps (NETs on implant surfaces. Our results provide new insight into neutrophil function during a foreign body response to peritoneal implants which has implications for the development of biologically compatible medical devices.

  20. Combined-load stress-strain relationship for advanced fiber composites

    Science.gov (United States)

    Chamis, C. C.; Sullivan, T. L.

    1975-01-01

    It was demonstrated experimentally that only one test specimen is required to determine the combined-load stress-strain relationships of a given fiber composite system. These relationships were determined using a thin angle-plied laminate tube and subjecting it to a number of combined-loading conditions. The measured data obtained are compared with theoretical predictions. Some important considerations associated with such a test are identified, and the significance of combined-load stress-strain relationships in certain practical designs are discussed.

  1. Numerical Evaluation of Size Effect on the Stress-Strain Behaviour of Geotextile-Reinforced Sand

    DEFF Research Database (Denmark)

    Hosseinpour, I.; Mirmoradi, S.H.; Barari, Amin

    2010-01-01

    This paper studies the effect of sample size on the stress-strain behavior and strength characteristics of geotextile reinforced sand using the finite element numerical analysis. The effect of sample size was investigated by studying the effects of varying the number of geotextile layers, the con......This paper studies the effect of sample size on the stress-strain behavior and strength characteristics of geotextile reinforced sand using the finite element numerical analysis. The effect of sample size was investigated by studying the effects of varying the number of geotextile layers...... on the mechanical behavior of reinforced sand decreases with an increase in the sample size....

  2. Summary report - development of laboratory tests and the stress- strain behaviour of Olkiluoto mica gneiss

    Energy Technology Data Exchange (ETDEWEB)

    Hakala, M.; Heikkilae, E. [Helsinki Univ. of Technology, Espoo (Finland). Lab. of Rock Engineering

    1997-05-01

    This work summarizes the project aimed at developing and qualifying a suitable combination of laboratory tests to establish a statistically reliable stress-strain behaviour of the main rock types at Posiva Oy`s detailed investigation sites for disposal of spent nuclear fuel. The work includes literature study of stress-strain behaviour of brittle rock, development and qualification of laboratory tests, suggested test procedures and interpretation methods and finally testing of Olkiluoto mica gneiss. The Olkiluoto study includes over 130 loading tests. Besides the commonly used laboratory tests, direct tensile tests, damage controlled tests and acoustic emission measurements were also carried out. (orig.) (54 refs.).

  3. Summary report - development of laboratory tests and the stress- strain behaviour of Olkiluoto mica gneiss

    International Nuclear Information System (INIS)

    Hakala, M.; Heikkilae, E.

    1997-05-01

    This work summarizes the project aimed at developing and qualifying a suitable combination of laboratory tests to establish a statistically reliable stress-strain behaviour of the main rock types at Posiva Oy's detailed investigation sites for disposal of spent nuclear fuel. The work includes literature study of stress-strain behaviour of brittle rock, development and qualification of laboratory tests, suggested test procedures and interpretation methods and finally testing of Olkiluoto mica gneiss. The Olkiluoto study includes over 130 loading tests. Besides the commonly used laboratory tests, direct tensile tests, damage controlled tests and acoustic emission measurements were also carried out. (orig.) (54 refs.)

  4. Nonlinear Stress-Strain Behavior of Plasma Sprayed Ceramic Coatings

    Czech Academy of Sciences Publication Activity Database

    Nohava, Jiří; Kroupa, František

    2005-01-01

    Roč. 50, č. 3 (2005), s. 251-262 ISSN 0001-7043 R&D Projects: GA AV ČR KSK1010104 Institutional research plan: CEZ:AV0Z20430508 Keywords : plasma spraying * ceramic coatings * Young’s modulus * nonlinear behavior * microcracks Subject RIV: JH - Ceramics, Fire-Resistant Materials and Glass

  5. Theoretical Development of an Orthotropic Elasto-Plastic Generalized Composite Material Model

    Science.gov (United States)

    Goldberg, Robert; Carney, Kelly; DuBois, Paul; Hoffarth, Canio; Harrington, Joseph; Rajan, Subramaniam; Blankenhorn, Gunther

    2014-01-01

    The need for accurate material models to simulate the deformation, damage and failure of polymer matrix composites is becoming critical as these materials are gaining increased usage in the aerospace and automotive industries. While there are several composite material models currently available within LSDYNA (Livermore Software Technology Corporation), there are several features that have been identified that could improve the predictive capability of a composite model. To address these needs, a combined plasticity and damage model suitable for use with both solid and shell elements is being developed and is being implemented into LS-DYNA as MAT_213. A key feature of the improved material model is the use of tabulated stress-strain data in a variety of coordinate directions to fully define the stress-strain response of the material. To date, the model development efforts have focused on creating the plasticity portion of the model. The Tsai-Wu composite failure model has been generalized and extended to a strain-hardening based orthotropic yield function with a nonassociative flow rule. The coefficients of the yield function, and the stresses to be used in both the yield function and the flow rule, are computed based on the input stress-strain curves using the effective plastic strain as the tracking variable. The coefficients in the flow rule are computed based on the obtained stress-strain data. The developed material model is suitable for implementation within LS-DYNA for use in analyzing the nonlinear response of polymer composites.

  6. Radioactive materials transportation emergency response plan

    International Nuclear Information System (INIS)

    Karmali, N.

    1987-05-01

    Ontario Hydro transports radioactive material between its nuclear facilities, Atomic Energy of Canada Limited at Chalk River Laboratories and Radiochemical Company in Kanata, on a regular basis. Ontario Hydro also occasionally transports to Whiteshell Laboratories, Hydro-Quebec and New Brunswick Electric Power Commission. Although there are stringent packaging and procedural requirements for these shipments, Ontario Hydro has developed a Radioactive Materials Transportation Emergency Response Plan in the event that there is an accident. The Transportation Emergency Response plan is based on six concepts: 1) the Province id divided into three response areas with each station (Pickering, Darlington, Bruce) having identified response areas; 2) response is activated via a toll-free number. A shift supervisor at Pickering will answer the call, determine the hazards involved from the central shipment log and provide on-line advice to the emergency worker. At the same time he will notify the nearest Ontario Hydro area office to provide initial corporate response, and will request the nearest nuclear station to provide response assistance; 3) all stations have capability in terms of trained personnel and equipment to respond to an accident; 4) all Ontario Hydro shipments are logged with Pickering NGS. Present capability is based on computerized logging with the computer located in the shift office at Pickering to allow quick access to information on the shipment; 5) there is a three tier structure for emergency public information. The local Area Manager is the first Ontario Hydro person at the scene of the accident. The responding facility technical spokesperson is the second line of Corporate presence and the Ontario Hydro Corporate spokesperson is notified in case the accident is a media event; and 6) Ontario Hydro will respond to non-Hydro shipments of radioactive materials in terms of providing assistance, guidance and capability. However, the shipper is responsible

  7. The study of the stress - strain state of the tank with bottom water drainage during operation

    Science.gov (United States)

    Shchipkova, Yu V.; Tokarev, V. V.

    2018-04-01

    Bottom drainage from tank is a current problem in modern tank usage. This article proposes the use of the bottom drainage system from the tank with the shape of the sloped cone to the centre of it. Changing the bottom design alters the stress - strain state to be analyzed in the Ansys. The analysis concluded that the proposed drainage system should be applied.

  8. Elevated temperature stress strain behavior of beryllium powder product

    International Nuclear Information System (INIS)

    Abeln, S.P.; Field, R.; Mataya, M.C.

    1995-01-01

    Several grades of beryllium powder product were tested under isothermal conditions in compression over a temperature range of room temperature to 1000 C and a strain rate range from 0.001 s -1 to 1 s -1 . Samples were compressed to a total strain of 1 (64% reduction in height). It is shown that all the grades are strain rate sensitive and that strain rate sensitivity increases with temperature. Yield points were exhibited by some grades up to a temperature of 500 C, and appeared to be primarily dependent on prior thermal history which determined the availability of mobile dislocations. Serrated flow in the form of stress drops was seen in all the materials tested and was most pronounced at 500 C. The appearance and magnitude of the stress drops were dependent on accumulated strain, strain rate, sample orientation, and composition. The flow stress and shape of the flow curves differed significantly from grade to grade due to variations in alloy content, the size and distribution of BeO particles, aging precipitates, and grain size. The ductile-brittle transition temperature (DBTT) was determined for each grade of material and shown to be dependent on composition and thermal treatment. Structure/property relationships are discussed using processing history, microscopy (light and transmission), and property data

  9. Stress-strain behavior under static loading in Gd123 high-temperature superconductors at 77 K

    Science.gov (United States)

    Fujimoto, Hiroyuki; Murakami, Akira; Teshima, Hidekazu; Morita, Mitsuru

    2013-10-01

    Mechanical properties of melt-growth GdBa2Cu3Ox (Gd123) superconducting samples with 10 wt.% Ag2O and 0.5 wt.% Pt were evaluated at 77 K through flexural tests for specimens cut from the samples in order to estimate the mechanical properties of the Gd123 material without metal substrates, buffer layers or stabilization layers. We discuss the mechanical properties; the Young's modulus and flexural strength with stress-strain behavior at 77 K. The results show that the flexural strength and fracture strain of Gd123 at 77 K are approximately 100 MPa and 0.1%, respectively, and that the origin of the fracture is defects such as pores, impurities and non-superconducting compounds. We also show that the Young's modulus of Gd123 is estimated to be 160-165 GPa.

  10. Stress-strain effects in alumina-Cu reinforced Nb3Sn wires fabricated by the tube process

    International Nuclear Information System (INIS)

    Murase, Satoru; Nakayama, Shigeo; Masegi, Tamaki; Koyanagi, Kei; Nomura, Shunji; Shiga, Noriyuki; Kobayashi, Norio; Watanabe, Kazuo.

    1997-01-01

    In order to fabricate a large-bore, high-field magnet which achieves a low coil weight and volume, a high strength compound superconducting wire is required. For those demands we have developed the reinforced Nb 3 Sn wire using alumina dispersion strengthened copper (alumina-Cu) as a reinforcement material and the tube process of the Nb 3 Sn wire fabrication. The ductility study of the composites which consisted of the reinforcement, Nb tube, Cu, and Cu clad Sn brought a 1 km long alumina-Cu reinforced Nb 3 Sn wire successfully. Using fabricated wires measurements and evaluations of critical current density as parameters of magnetic field, tensile stress, tensile strain, and transverse compressive stress, and those of stress-strain curves at 4.2 K were performed. They showed superior performance such as high 0.3% proof stress (240 MPa at 0.3% strain) and high maximum tolerance stress (320 MPa) which were two times as large as those of conventional Cu matrix Nb 3 Sn wire. The strain sensitivity parameters were obtained for the reinforced Nb 3 Sn wire and the Cu matrix one using the scaling law. Residual stress of the component materials caused by cooling down to 4.2 K from heat-treatment temperature was calculated using equivalent Young's modulus, equivalent yield strength, thermal expansion coefficient and other mechanical parameters. Calculated stress-strain curves at 4.2 K for the reinforced Nb 3 Sn wire and the Cu matrix one based on calculation of residual stress, had good agreement with the experimental values. (author)

  11. The elastic response of composite materials

    International Nuclear Information System (INIS)

    Laws, N.

    1980-01-01

    The theory of linear elasticity is used to study the elastic response of composite materials. The main concern is the prediction of overall moduli. Some attention is paid to the problem of deciding upon when the idea of an overall modulus is meaningful. In addition it is shown how to calculate some rigorous bounds on the overall moduli, and some predictions of the self-consistent method are discussed. The paper mainly concentrates on isotropic dispersions of spheres, unidirectional fibre-reinforced materials and laminates. (author)

  12. Effect on stress-strain relations brought by surface carburization of 316 stainless steel

    Energy Technology Data Exchange (ETDEWEB)

    Matsumoto, K [Ishikawajima-Harima Heavy Industries, Tokyo (Japan)

    1977-07-01

    The effect of sodium. environment on austenitic stainless steels used as structural materials in Liquid Metal Cooled Fast Breeder Reactors (LMFBRs) has long been the subject of extensive studies in many countries. Recent developments tending toward stricter control of the oxygen content permitted to be present in the circulating sodium have come to allay the apprehensions formerly held on the possibility of general corrosion affecting the mechanical properties of structural materials expected to be used In LMFBR plants. Grain boundary corrosion and depletion of elements from the structure surface also have come to be considered to provide little cause of fear in this regard, though some uncertainty is still left concerning the influence that these phenomena might exert toward the end of plant life. What still remains essentially to be clarified relates to carbon mass transfer. Decarburization and/or carburization are phenomena that cannot be disregarded even in the primary heat transfer system of LMFBRs, on account of the temperature dependence of carbon activity in steels, which could cause the carbon to leak out from structural material into the circulating sodium in the higher temperature zones of a circuit, to deposit itself on the channel walls in the lower temperature parts. Recent reports on loop experiments point toward the possibility of carboneous matter leaching into flowing sodium and into the cover gas to produce significant carburization phenomena. Carburization, in particular, can bring about loss of ductility and deterioration of fatigue properties, and hence serious consideration of this aspect is called for in the design of components incorporating thin stainless steel plates. To represent the stress-strain behavior at 550 deg. C of 316 stainless steel affected by surface carburization, an empirical formula was adopted. It was proposed by Voce for relating true stress to true plastic strain: {sigma} = Aexp(C {epsilon}{sub p} ) + B, where {sigma

  13. Effect on stress-strain relations brought by surface carburization of 316 stainless steel

    International Nuclear Information System (INIS)

    Matsumoto, K.

    1977-01-01

    The effect of sodium. environment on austenitic stainless steels used as structural materials in Liquid Metal Cooled Fast Breeder Reactors (LMFBRs) has long been the subject of extensive studies in many countries. Recent developments tending toward stricter control of the oxygen content permitted to be present in the circulating sodium have come to allay the apprehensions formerly held on the possibility of general corrosion affecting the mechanical properties of structural materials expected to be used In LMFBR plants. Grain boundary corrosion and depletion of elements from the structure surface also have come to be considered to provide little cause of fear in this regard, though some uncertainty is still left concerning the influence that these phenomena might exert toward the end of plant life. What still remains essentially to be clarified relates to carbon mass transfer. Decarburization and/or carburization are phenomena that cannot be disregarded even in the primary heat transfer system of LMFBRs, on account of the temperature dependence of carbon activity in steels, which could cause the carbon to leak out from structural material into the circulating sodium in the higher temperature zones of a circuit, to deposit itself on the channel walls in the lower temperature parts. Recent reports on loop experiments point toward the possibility of carboneous matter leaching into flowing sodium and into the cover gas to produce significant carburization phenomena. Carburization, in particular, can bring about loss of ductility and deterioration of fatigue properties, and hence serious consideration of this aspect is called for in the design of components incorporating thin stainless steel plates. To represent the stress-strain behavior at 550 deg. C of 316 stainless steel affected by surface carburization, an empirical formula was adopted. It was proposed by Voce for relating true stress to true plastic strain: σ = Aexp(C ε p ) + B, where σ is the true stress, and

  14. The constitutive response of three solder materials

    International Nuclear Information System (INIS)

    Perez-Bergquist, Alejandro G.; Cao Fang; Perez-Bergquist, Sara J.; Lopez, Mike F.; Trujillo, Carl P.; Cerreta, Ellen K.; Gray, George T.

    2012-01-01

    Highlights: ► The full constitutive response of three solder materials. ► Test temperatures from −196 °C to 60 °C and strain rates from 10 −3 to >10 3 s −1 . ► Substitutes for leaded solders from a mechanical/microstructural properties view. - Abstract: As increasing worldwide demand for portable consumer electronics drives development of smaller, faster, more powerful electronic devices, components in these devices must become smaller, more precise, and more robust. Often, failure of these devices comes as a result of failure of the package (i.e. when a mobile phone is dropped) and specifically comes as a result of failure of solder interconnects. As a result, stronger more reliable solder materials are needed. In this paper, the constitutive responses of three solder materials (Sn63Pb37, Sn62Pb36Ag2, and Sn96.5Ag3Cu0.5) are analyzed as a function of temperature (−196 °C to 60 °C) and strain rate (10 −3 to >10 3 s −1 ). The lead-free Sn96.5Ag3Cu0.5 possessed the highest yield stress of the three solders at all tested strain rates and temperatures, and all solder microstructures which displayed a mechanical response that was sensitive to temperature exhibited grain coarsening with increasing plastic strain, even at room temperature.

  15. The constitutive response of three solder materials

    Energy Technology Data Exchange (ETDEWEB)

    Perez-Bergquist, Alejandro G., E-mail: alexpb@lanl.gov [Materials Science and Technology Division, Los Alamos National Laboratory, Mail Stop G755, Los Alamos, NM 87545 (United States); Cao Fang [Exxon Mobil Research and Engineering Company, Annadale, NJ 08801 (United States); Perez-Bergquist, Sara J.; Lopez, Mike F.; Trujillo, Carl P.; Cerreta, Ellen K.; Gray, George T. [Materials Science and Technology Division, Los Alamos National Laboratory, Mail Stop G755, Los Alamos, NM 87545 (United States)

    2012-05-25

    Highlights: Black-Right-Pointing-Pointer The full constitutive response of three solder materials. Black-Right-Pointing-Pointer Test temperatures from -196 Degree-Sign C to 60 Degree-Sign C and strain rates from 10{sup -3} to >10{sup 3} s{sup -1}. Black-Right-Pointing-Pointer Substitutes for leaded solders from a mechanical/microstructural properties view. - Abstract: As increasing worldwide demand for portable consumer electronics drives development of smaller, faster, more powerful electronic devices, components in these devices must become smaller, more precise, and more robust. Often, failure of these devices comes as a result of failure of the package (i.e. when a mobile phone is dropped) and specifically comes as a result of failure of solder interconnects. As a result, stronger more reliable solder materials are needed. In this paper, the constitutive responses of three solder materials (Sn63Pb37, Sn62Pb36Ag2, and Sn96.5Ag3Cu0.5) are analyzed as a function of temperature (-196 Degree-Sign C to 60 Degree-Sign C) and strain rate (10{sup -3} to >10{sup 3} s{sup -1}). The lead-free Sn96.5Ag3Cu0.5 possessed the highest yield stress of the three solders at all tested strain rates and temperatures, and all solder microstructures which displayed a mechanical response that was sensitive to temperature exhibited grain coarsening with increasing plastic strain, even at room temperature.

  16. Stress/strain characteristics of Cu alloy sheath in situ processed MgB2 superconducting wires

    International Nuclear Information System (INIS)

    Katagiri, Kazumune; Kasaba, Koichi; Shoji, Yoshitaka

    2005-01-01

    The mechanical properties of copper and copper alloy (Cu-Zr, Cu-Be and Cu-Cr) sheath in situ PIT-processed MgB 2 superconducting wires were studied at room temperature (RT) and 4.2 K. The effects of stress-strain on the critical current (I c ) of the wires have also been studied at 4.2 K and in magnetic fields up to 5 T. It has been clarified that alloying the Cu sheath significantly increases the yield and flow stresses of the wires at both RT and 4.2 K. The 0.5% flow stresses of the Cu alloy sheath wire were 147-237 MPa, whereas that of Cu was 55 MPa. At RT, serration corresponding to multiple cracking was observed around a strain of 0.4% and the stress-strain curves saturated beyond that point. The strain dependence of I c prior to the critical strain (ε irr ) was different depending on the magnetic field; being almost constant at 2 T and increasing with strain at 5 T. The I c decreased beyond ε irr , which is much larger for Cu alloy sheath wires as compared to Cu sheath wire. This is due to the difference in the residual compressive strain in the MgB 2 core during cooling from the heat-treatment temperature to 4.2 K, which is determined through relaxation by yielding in the sheath materials. The transverse compression tests revealed that the I c of the Cu alloy sheath wire did not degrade up to 314 MPa, which is also higher than that of Cu sheath wire. (author)

  17. Biomimetic materials for controlling bone cell responses.

    Science.gov (United States)

    Drevelle, Olivier; Faucheux, Nathalie

    2013-01-01

    Bone defects that cannot "heal spontaneously during life" will become an ever greater health problem as populations age. Harvesting autografts has several drawbacks, such as pain and morbidity at both donor and acceptor sites, the limited quantity of material available, and frequently its inappropriate shape. Researchers have therefore developed alternative strategies that involve biomaterials to fill bone defects. These biomaterials must be biocompatible and interact with the surrounding bone tissue to allow their colonization by bone cells and blood vessels. The latest generation biomaterials are not inert; they control cell responses like adhesion, proliferation and differentiation. These biomaterials are called biomimetic materials. This review focuses on the development of third generation materials. We first briefly describe the bone tissue with its cells and matrix, and then how bone cells interact with the extracellular matrix. The next section covers the materials currently used to repair bone defects. Finally, we describe the strategies employed to modify the surface of materials, such as coating with hydroxyapatite and grafting biomolecules.

  18. Observations of hydrotectonic stress/strain events at a basement high at the Nicoya outer rise

    Science.gov (United States)

    Tryon, M. D.; Brown, K. M.

    2005-12-01

    instruments. A few indicate downflow while the others show upflow. This sort of response would be expected during a stress event causing regions of compression and dilation. These results suggest that ridge flank basement highs may be good sites to monitor stress/strain events as well as basement hydrology.

  19. Analysis of stress-strain behavior in Bi2223 composite tapes

    International Nuclear Information System (INIS)

    Sugano, M.; Osamura, K.; Nyilas, A.

    2004-01-01

    Tensile test was carried out for Bi2223/Ag/Ag alloy composite tapes at RT, 77 and 7 K. Two yielding points are observed in the stress-strain curves. From the stress-strain behavior of the components and critical current (I c ) as a function of tensile strain, it was found that the microscopic reason for these yieldings is attributed to yielding of Ag alloy and fracture of Bi2223, respectively. The strain at the second yielding has temperature dependence and it becomes larger with decreasing measured temperature. From the thermo-mechanical analysis, it can be explained by temperature dependence of compressive residual strain of Bi2223. Reversible recovery of I c was found during loading-unloading test. The relationship between the reversible strain limit and the intrinsic strain of Bi2223 was discussed

  20. The mechanical behaviour of NBR/FEF under compressive cyclic stress strain

    Science.gov (United States)

    Mahmoud, W. E.; El-Eraki, M. H. I.; El-Lawindy, A. M. Y.; Hassan, H. H.

    2006-06-01

    Acrylonitrile butadiene rubber compounds filled with different concentrations of fast extrusion furnace (FEF) carbon black were experimentally investigated. The stress-strain curves of the composites were studied, which suggest good filler-matrix adhesion. The large reinforcement effect of the filler followed the Guth model for non-spherical particles. The effect of FEF carbon black on the cyclic fatigue and hysteresis was also examined. The loading and unloading stress-strain relationships for any cycle were described by applying Ogden's model for rubber samples. The dissipation energy that indicates the vibration damping capacity for all samples was determined. A simple model was proposed, to investigate the relation between maximum stress and the number of cyclic fatigue.

  1. The mechanical behaviour of NBR/FEF under compressive cyclic stress-strain

    Energy Technology Data Exchange (ETDEWEB)

    Mahmoud, W E [Faculty of Science, Physics Department, Suez Canal University, Ismailia (Egypt); El-Eraki, M H I [Faculty of Science, Physics Department, Suez Canal University, Ismailia (Egypt); El-Lawindy, A M Y [Faculty of Science, Physics Department, Suez Canal University, Ismailia (Egypt); Hassan, H H [Faculty of Science, Physics Department, Cairo University, Giza (Egypt)

    2006-06-07

    Acrylonitrile butadiene rubber compounds filled with different concentrations of fast extrusion furnace (FEF) carbon black were experimentally investigated. The stress-strain curves of the composites were studied, which suggest good filler-matrix adhesion. The large reinforcement effect of the filler followed the Guth model for non-spherical particles. The effect of FEF carbon black on the cyclic fatigue and hysteresis was also examined. The loading and unloading stress-strain relationships for any cycle were described by applying Ogden's model for rubber samples. The dissipation energy that indicates the vibration damping capacity for all samples was determined. A simple model was proposed, to investigate the relation between maximum stress and the number of cyclic fatigue.

  2. The study of stress-strain state of stabilized layered soil foundations

    Directory of Open Access Journals (Sweden)

    Sokolov Mikhail V.

    2017-01-01

    Full Text Available Herein presented are the results of modeling and analysis of stress-strain state of layered inhomogeneous foundation soil when it is stabilised by injection to different depths. Produced qualitative and quantitative analysis of the components of the field of isolines of stresses, strains, stress concentration and the difference between the strain at the boundary of different elastic horizontal layers. Recommendations are given for the location of stabilised zones in relation to the border of different elastic layers. In particular, it found that stabilization of soil within the weak layer is inappropriate, since it practically provides no increase in the stability of the soil foundation, and when performing stabilisation of soil foundations, it is recommended to place the lower border of the stabilisation zone below the border of a stronger layer, at this the distribution of stresses and strains occurs more evenly, and load-bearing capacity of this layer is used to the maximum.

  3. Stress-Strain Law for Confined Concrete with Hardening or Softening Behavior

    Directory of Open Access Journals (Sweden)

    Piero Colajanni

    2013-01-01

    Full Text Available This paper provides a new general stress-strain law for concrete confined by steel, fiber reinforced polymer (FRP, or fiber reinforced cementitious matrix (FRCM, obtained by a suitable modification of the well-known Sargin’s curve for steel confined concrete. The proposed law is able to reproduce stress-strain curve of any shape, having both hardening or softening behavior, by using a single closed-form simple algebraic expression with constant coefficients. The coefficients are defined on the basis of the stress and the tangent modulus of the confined concrete in three characteristic points of the curve, thus being related to physical meaningful parameters. It will be shown that if the values of the parameters of the law are deduced from experimental tests, the model is able to accurately reproduce the experimental curve. If they are evaluated on the basis of an analysis-oriented model, the proposed model provides a handy equivalent design model.

  4. The mechanical behaviour of NBR/FEF under compressive cyclic stress-strain

    International Nuclear Information System (INIS)

    Mahmoud, W E; El-Eraki, M H I; El-Lawindy, A M Y; Hassan, H H

    2006-01-01

    Acrylonitrile butadiene rubber compounds filled with different concentrations of fast extrusion furnace (FEF) carbon black were experimentally investigated. The stress-strain curves of the composites were studied, which suggest good filler-matrix adhesion. The large reinforcement effect of the filler followed the Guth model for non-spherical particles. The effect of FEF carbon black on the cyclic fatigue and hysteresis was also examined. The loading and unloading stress-strain relationships for any cycle were described by applying Ogden's model for rubber samples. The dissipation energy that indicates the vibration damping capacity for all samples was determined. A simple model was proposed, to investigate the relation between maximum stress and the number of cyclic fatigue

  5. In situ subsoil stress-strain behaviour in relation to soil precompression stress

    DEFF Research Database (Denmark)

    Keller, T; Arvidsson, J; Schjønning, Per

    2012-01-01

    is assumed to be elastic and reversible as long as [sigma] work examined soil stress-strain behavior as measured in situ during wheeling experiments and related it to the stress-strain behavior and [sigma]pc measured on soil cores in uniaxial compression tests in the laboratory. The data......Soil compaction negatively influences many important soil functions, including crop growth. Compaction occurs when the applied stress, [sigma], overcomes the soil strength. Soil strength in relation to compaction is typically expressed by the soil precompression stress, [sigma]pc. Deformation...... analyzed were from a large number of wheeling experiments carried out in Sweden and Denmark on soils with a wide range of texture. Contradicting the concept of precompression stress, we observed residual strain, [Latin Small Letter Open E]res, at [sigma

  6. Effect of nonlinear stress-strain relationship on bending strength of isotropic graphite

    International Nuclear Information System (INIS)

    Arai, Taketoshi; Oku, Tatsuo

    1978-05-01

    Four-point bending tests were made on rectangular isotropic 7477PT graphite specimens of different sizes to observe the relation between load and outermost fiber strain. Analytical methods, allowing for nonlinear stress-strain relationships different between tension and compression, were developed for calculating the fiber stress distribution in a beam and the failure probability based on the Weibull statistical theory for bending fracture. With increase of the stress, the stress-strain curves for tension deviate from the linearity and also from those for compression. The true bending strengths of the rectangular bars are 10 -- 20 percent lower than elastic bending strengths. Revised Weibull theory gives failure probability distributions agreeing with measured ones, compared with the theory based on elastic behavior. (auth.)

  7. Simulation of Stress-Strain State of Shovel Rotary Support Kingpin

    Science.gov (United States)

    Khoreshok, A. A.; Buyankin, P. V.; Vorobiev, A. V.; Dronov, A. A.

    2016-04-01

    The article presents the sequence of computational simulation of stress-strain state of shovel’s rotary support. Computation results are analyzed, the kingpin is specified as the most loaded element, maximum stress zones are identified. Kingpin design modification such as enhancement of fillet curvature radius to 25 mm and displacement of eyebolt holes on the diameter of 165 mm are proposed, thus diminishing impact of stress concentrators and improving reliability of the rotary support.

  8. Formation of stress/strain cycles for analytical assessment of fatigue crack initiation and growth

    International Nuclear Information System (INIS)

    Tashkinov, A.V.

    2005-01-01

    This paper discusses standard techniques for setting up cycles of stresses, strains and stress intensity factors (SIF) for use in analysing the fatigue characteristics of crack-free components or the fatigue crack growth if crack-like flaws are present. A number of improved techniques are proposed. An enhanced procedure for analytical description of true metal stress-strain curves, covering plastic effects, is presented. This procedure involves standard physical and mechanical properties of the metal in question, such as ultimate stress, yield stress and elasticity modulus. It is emphasized that the currently practiced rain-flow method of design cycle formation, which is effective for an actual (truly known) cyclic loading history, is not suitable for a projected (anticipated) history, as it leaves out of account possible variations in the sequence of operating conditions. Improved techniques for establishing design stress/strain and SIF cycles are described, which make allowance for the most unfavourable sequence of events in the projected loading history. The paper points to a basic difference in the methods of design cycle formation, employed in assessment of the current condition of a component (with the actual history accounted for) and in estimation of the residual lifetime or life extension (for a projected history). (authors)

  9. Stress strain modelling of casting processes in the framework of the control volume method

    DEFF Research Database (Denmark)

    Hattel, Jesper; Andersen, Søren; Thorborg, Jesper

    1998-01-01

    Realistic computer simulations of casting processes call for the solution of both thermal, fluid-flow and stress/strain related problems. The multitude of the influencing parameters, and their non-linear, transient and temperature dependent nature, make the calculations complex. Therefore the nee......, the present model is based on the mainly decoupled representation of the thermal, mechanical and microstructural processes. Examples of industrial applications, such as predicting residual deformations in castings and stress levels in die casting dies, are presented...... for fast, flexible, multidimensional numerical methods is obvious. The basis of the deformation and stress/strain calculation is a transient heat transfer analysis including solidification. This paper presents an approach where the stress/strain and the heat transfer analysis uses the same computational...... domain, which is highly convenient. The basis of the method is the control volume finite difference approach on structured meshes. The basic assumptions of the method are shortly reviewed and discussed. As for other methods which aim at application oriented analysis of casting deformations and stresses...

  10. An Experimental Study of Mortars with Recycled Ceramic Aggregates: Deduction and Prediction of the Stress-Strain

    Directory of Open Access Journals (Sweden)

    Francisca Guadalupe Cabrera-Covarrubias

    2016-12-01

    Full Text Available The difficult current environmental situation, caused by construction industry residues containing ceramic materials, could be improved by using these materials as recycled aggregates in mortars, with their processing causing a reduction in their use in landfill, contributing to recycling and also minimizing the consumption of virgin materials. Although some research is currently being carried out into recycled mortars, little is known about their stress-strain (σ-ε; therefore, this work will provide the experimental results obtained from recycled mortars with recycled ceramic aggregates (with contents of 0%, 10%, 20%, 30%, 50% and 100%, such as the density and compression strength, as well as the σ-ε curves representative of their behavior. The values obtained from the analytical process of the results in order to finally obtain, through numerical analysis, the equations to predict their behavior (related to their recycled content are those of: σ (elastic ranges and failure maximum, ε (elastic ranges and failure maximum, and Resilience and Toughness. At the end of the investigation, it is established that mortars with recycled ceramic aggregate contents of up to 20% could be assimilated just like mortars with the usual aggregates, and the obtained prediction equations could be used in cases of similar applications.

  11. Casting and stress-strain simulations of a cast ductile iron component using microstructure based mechanical behavior

    International Nuclear Information System (INIS)

    Olofsson, Jakob; Svensson, Ingvar L

    2012-01-01

    The industrial demand for increased component performance with concurrent reductions in component weight, development times and verifications using physical prototypes drives the need to use the full potential of casting and Finite Element Method (FEM) simulations to correctly predict the mechanical behavior of cast components in service. The mechanical behavior of the component is determined by the casting process, and factors as component geometry and casting process parameters are known to affect solidification and microstructure formation throughout the component and cause local variations in mechanical behavior as well as residual stresses. Though residual stresses are known to be an important factor in the mechanical behavior of the component, the importance of local mechanical behavior is not well established and the material is typically considered homogeneous throughout the component. This paper deals with the influence of solidification and solid state transformation on microstructure formation and the effect of local microstructure variations on the mechanical behavior of the cast component in service. The current work aims to investigate the coupling between simulation of solidification, microstructure and local variations in mechanical behavior and stress-strain simulation. This is done by performing several simulations of a ductile iron component using a recently developed simulation strategy, a closed chain of simulations for cast components, able to predict and describe the local variations in not only elastic but also plastic behavior throughout the component by using microstructural parameters determined by simulations of microstructural evolution in the component during the casting process. In addition the residual stresses are considered. The results show that the FEM simulation results are significantly affected by including microstructure based mechanical behavior. When the applied load is low and the component is subjected to stress levels

  12. Stress-strain time-dependent behavior of A356.0 aluminum alloy subjected to cyclic thermal and mechanical loadings

    Science.gov (United States)

    Farrahi, G. H.; Ghodrati, M.; Azadi, M.; Rezvani Rad, M.

    2014-08-01

    This article presents the cyclic behavior of the A356.0 aluminum alloy under low-cycle fatigue (or isothermal) and thermo-mechanical fatigue loadings. Since the thermo-mechanical fatigue (TMF) test is time consuming and has high costs in comparison to low-cycle fatigue (LCF) tests, the purpose of this research is to use LCF test results to predict the TMF behavior of the material. A time-independent model, considering the combined nonlinear isotropic/kinematic hardening law, was used to predict the TMF behavior of the material. Material constants of this model were calibrated based on room-temperature and high-temperature low-cycle fatigue tests. The nonlinear isotropic/kinematic hardening law could accurately estimate the stress-strain hysteresis loop for the LCF condition; however, for the out-of-phase TMF, the condition could not predict properly the stress value due to the strain rate effect. Therefore, a two-layer visco-plastic model and also the Johnson-Cook law were applied to improve the estimation of the stress-strain hysteresis loop. Related finite element results based on the two-layer visco-plastic model demonstrated a good agreement with experimental TMF data of the A356.0 alloy.

  13. Extracting material response from simple mechanical tests on hardening-softening-hardening viscoplastic solids

    Science.gov (United States)

    Mohan, Nisha

    Uniaxial Compression of Vertically Aligned Carbon Nanotubes," J. Mech.Phys. Solids, 59, pp. 2227--2237, Erratum 60, 1753-1756 (2012)], the property space exploration was advanced to three types of simple mechanical tests: 1) uniaxial compression, 2) uniaxial tension, and 3) nanoindentation with a conical and a flat-punch tip. The simulations attempt to explain some of the salient features in experimental data, like 1) The initial linear elastic response. 2) One or more nonlinear instabilities, yielding, and hardening. The model-inherent relationships between the material properties and the overall stress-strain behavior were validated against the available experimental data. The material properties include the gradient in stiffness along the height, plastic and elastic compressibility, and hardening. Each of these tests was evaluated in terms of their efficiency in extracting material properties. The uniaxial simulation results proved to be a combination of structural and material influences. Out of all deformation paths, flat-punch indentation proved to be superior since it is the most sensitive in capturing the material properties.

  14. Model-based methodology to develop the isochronous stress-strain curves for modified 9Cr steels

    International Nuclear Information System (INIS)

    Kim, Woo Gon; Yin, Song Nan; Kim, Sung Ho; Lee, Chan Bock; Jung, Ik Hee

    2008-01-01

    Since high temperature materials are designed with a target life based on a specified amount of allowable strain and stress, their Isochronous Stress-Strain Curves (ISSC) are needed to avoid an excessive deformation during an intended service life. In this paper, a model-based methodology to develop the isochronous curves for a G91 steel is described. Creep strain-time curves were reviewed for typical high-temperature materials, and Garofalo's model which conforms well to the primary and secondary creep stages was proper for the G91 steel. Procedures to obtain an instantaneous elastic-plastic strain, ε i were given in detail. Also, to accurately determine the P 1 , P 2 and P 3 parameters in the Garofalo's model, a Nonlinear Least Square Fitting (NLSF) method was adopted and useful. The long-term creep curves for the G91 steel can be modeled by the Garofalo's model, and the long-term ISSCs can be developed using the modeled creep curves

  15. Undirected learning styles and academic risk: Analysis of the impact of stress, strain and coping.

    Science.gov (United States)

    Kimatian, Stephen; Lloyd, Sara; Berger, Jeffrey; Steiner, Lorraine; McKay, Robert; Schwengal, Deborah

    2017-01-01

    Learning style inventories used in conjunction with a measure of academic achievement consistently show an association of meaning directed learning patterns with academic success, but have failed to show a clear association of undirected learning styles with academic failure. Using survey methods with anesthesia residents, this study questioned whether additional assessment of factors related to stress, strain, and coping help to better define the association between undirected learning styles and academic risk. Pearson chi squared tests. 296 subjects were enrolled from eight institutions with 142 (48%) completing the study. American Board of Anesthesiologists In Training Examinations (ITE) percentiles (ITE%) were used as a measure of academic achievement. The Vermunt Inventory of Learning Styles (ILS) was used to identify four learning patterns and 20 strategies, and the Osipow Stress Inventory-Revised (OSI-R) was used as a measure of six scales of occupational stress, four of personal strain, and four coping resources. Two learning patterns had significant relationship with ITE scores. As seen in previous studies, Meaning Directed Learning was beneficial for academic achievement while Undirected Learning was the least beneficial. Higher scores on Meaning Directed Learning correlated positively with higher ITE scores while higher Undirected and lower Meaning Directed patterns related negatively to ITE%. OSI-R measures of stress, strain and coping indicated that residents with Undirected learning patterns had higher scores on three scales related to stress, and 4 related to strain, while displaying lower scores on two scales related to coping. Residents with higher Meaning Directed patterns scored lower on two scales of stress and two scales of strain, with higher scores on two scales for coping resources. Low Meaning Directed and high Undirected learning patterns correlated with lower ITE percentiles, higher scores for stress and strain, and lower coping resources

  16. Main results of BN-600 reactor stress-strain state investigations

    International Nuclear Information System (INIS)

    Panov, V.A.

    1983-01-01

    The development of BN-600 fast reactor plant needed the solution of a series of complex engineering problems including ones for confirming integrity of the most vital structural components. The particular attention was given to the main vessel since reactor availability end safe operation of the plant as a whole depend on vessel strength end integrity. The present report deals with the main results of theoretical and experimental investigations of the stress-strain state of BN-600 reactor vessel carried out during design, start-up and initial bringing the reactor to power

  17. Spall damage of a mild carbon steel: Effects of peak stress, strain rate and pulse duration

    International Nuclear Information System (INIS)

    Li, C.; Li, B.; Huang, J.Y.; Ma, H.H.; Zhu, M.H.; Zhu, J.; Luo, S.N.

    2016-01-01

    We investigate spall damage of a mild carbon steel under high strain-rate loading, regarding the effects of peak stress, strain rate, and pulse duration on spall strength and damage, as well as related microstructure features, using gas gun plate impact, laser velocimetry, and electron backscatter diffraction analysis. Our experiments demonstrate strong dependences of spall strength on peak stress and strain rate, and its weak dependence on pulse duration. We establish numerical relations between damage and peak stress or pulse duration. Brittle and ductile spall fracture modes are observed at different loading conditions. Damage nucleates at grain boundaries and triple junctions, either as transgranular cleavage cracks or voids.

  18. Spall damage of a mild carbon steel: Effects of peak stress, strain rate and pulse duration

    Energy Technology Data Exchange (ETDEWEB)

    Li, C. [College of Physical Science and Technology, Sichuan University, Chengdu, Sichuan 610064 (China); Key Laboratory of Advanced Technologies of Materials, Ministry of Education, Southwest Jiaotong University, Chengdu, Sichuan 610031 (China); The Peac Institute of Multiscale Sciences, Chengdu, Sichuan 610031 (China); Li, B.; Huang, J.Y. [The Peac Institute of Multiscale Sciences, Chengdu, Sichuan 610031 (China); CAS Key Laboratory of Mechanical Behavior and Design of Materials, Department of Modern Mechanics, University of Science and Technology of China, Hefei, Anhui 230027 (China); Ma, H.H. [CAS Key Laboratory of Mechanical Behavior and Design of Materials, Department of Modern Mechanics, University of Science and Technology of China, Hefei, Anhui 230027 (China); Zhu, M.H. [Key Laboratory of Advanced Technologies of Materials, Ministry of Education, Southwest Jiaotong University, Chengdu, Sichuan 610031 (China); Zhu, J., E-mail: zhujun01@163.com [College of Physical Science and Technology, Sichuan University, Chengdu, Sichuan 610064 (China); Luo, S.N., E-mail: sluo@pims.ac.cn [The Peac Institute of Multiscale Sciences, Chengdu, Sichuan 610031 (China); Key Laboratory of Advanced Technologies of Materials, Ministry of Education, Southwest Jiaotong University, Chengdu, Sichuan 610031 (China)

    2016-04-13

    We investigate spall damage of a mild carbon steel under high strain-rate loading, regarding the effects of peak stress, strain rate, and pulse duration on spall strength and damage, as well as related microstructure features, using gas gun plate impact, laser velocimetry, and electron backscatter diffraction analysis. Our experiments demonstrate strong dependences of spall strength on peak stress and strain rate, and its weak dependence on pulse duration. We establish numerical relations between damage and peak stress or pulse duration. Brittle and ductile spall fracture modes are observed at different loading conditions. Damage nucleates at grain boundaries and triple junctions, either as transgranular cleavage cracks or voids.

  19. Determination of stress-strain state of the wooden church log walls with software package

    Directory of Open Access Journals (Sweden)

    Chulkova Anastasia

    2016-01-01

    Full Text Available The restoration of architectural monuments is going on all over the world today. The main aim of restoration is the renewal of stable functioning of building constructions in normal state. In this article, we have tried to figure out with special software the bearing capacity of log cabins of the Church of Transfiguration on Kizhi island. As shown in research results, determination of stress-strain stage with software package is necessary for the bearing capacity computation as well as field tests.

  20. Switchable and responsive surfaces and materials for biomedical applications

    CERN Document Server

    Zhang, Johnathan

    2015-01-01

    Surface modification of biomaterials can ultimately determine whether a material is accepted or rejected from the human body, and a responsive surface can further make the material ""smart"" and ""intelligent"". Switchable and Responsive Surfaces and Materials for Biomedical Applications outlines synthetic and biological materials that are responsive under different stimuli, their surface design and modification techniques, and applicability in regenerative medicine/tissue engineering,  drug delivery, medical devices, and biomedical diagnostics. Part one provides a detailed overview of swit

  1. Extremal Overall Elastic Response of Polycrystalline Materials

    DEFF Research Database (Denmark)

    Bendsøe, Martin P; Lipton, Robert

    1997-01-01

    Polycrystalline materials comprised of grains obtained from a single anisotropic material are considered in the framework of linear elasticity. No assumptions on the symmetry of the polycrystal are made. We subject the material to independent external strain and stress fields with prescribed mean...

  2. Dynamic Deformation Behavior of Soft Material Using Shpb Technique and Pulse Shaper

    Science.gov (United States)

    Lee, Ouk Sub; Cho, Kyu Sang; Kim, Sung Hyun; Han, Yong Hwan

    This paper presents a modified Split Hopkinson Pressure Bar (SHPB) technique to obtain compressive stress strain data for NBR rubber materials. An experimental technique with a modified the conventional SHPB has been developed for measuring the compressive stress strain responses of materials with low mechanical impedance and low compressive strengths, such as the rubber and the polymeric material. This paper uses an aluminum pressure bar to achieve a closer impedance match between the pressure bar and the specimen materials. In addition, a pulse shaper is utilized to lengthen the rising time of the incident pulse to ensure dynamic stress equilibrium and homogeneous deformation of NBR rubber materials. It is found that the modified technique can determine the dynamic deformation behavior of rubbers more accurately.

  3. The Mine Working's Roof Stress-strain State Research in the Perspective of Development of New Coal Deposits of Kuzbass

    Science.gov (United States)

    Kostyuk, Svetlana; Bedarev, Nikolay; Lyubimov, Oleg; Shaikhislamov, Arthur

    2017-11-01

    The present now normative and information base is regulating of the Kuzbass coal seams treatment but is not considering of the mining-geological and mining-engineering conditions for new coal deposits. The analysis of works for the research of the rock pressure manifestation shows that in many cases numerous results require of the practical confirmation in mine conditions directly, and also confirmation by the physical models. This work reflects one of the stages of research on changing the stress-strain state of the massif with the formation of unloading zones, increased rock pressure, and recovery. As an example, the results of the information analysis obtained by means of contour and depth benchmarks on the ventilation drift in the course of the 34 seam treatment at the "Tagaryshskaya" mine are presented. The differences of the analyzed results from the results obtained in the conditions of other mines are established. The values of the drift's roof stratification on the contour and at the distance from the contour of 1.0 to 4.0 m are given. The revealed maximums of the rock pressure and pressure changes in the hydraulic supports of the complex used for movement are presented. Recommendations on the choice of the anchor's length taking into account the roof stratification size are given. The further research stages on models from equivalent materials at various geometric scales are proposed.

  4. Probabilistic molecular dynamics evaluation of the stress-strain behavior of polyethylene

    International Nuclear Information System (INIS)

    Stowe, J.Q.; Predecki, P.K.; Laz, P.J.; Burks, B.M.; Kumosa, M.

    2009-01-01

    The primary goal of this study was to utilize molecular dynamics to predict the mechanical behavior of polyethylene. In particular, stress-strain relationships, the Young's modulus and Poisson ratio were predicted for low-density polyethylene at several molecular weights and polymer configurations with the number of united CH 2 atoms ranging between 500 and 5000. Probabilistic Monte Carlo methods were also used to identify the extent of uncertainty in mechanical property predictions. In general, asymptotic behavior was observed for stress and the Young's modulus as the molecular weight of the models increased. At the same time, significant variability, of the order of 1000% of the mean, in the stress-strain relationships and the Young's modulus predictions was observed, especially for low molecular weight models. The variability in the Young's modulus predictions ranged from 17.9 to 3.2 GPa for the models ranging from 100 to 5000 CH 2 atom models. However, it was also found that the mean value of the Young's modulus approached a physically possible value of 194 MPa for the 5000 atom model. Poisson ratio predictions also resulted in significant variability, from 200% to 425% of the mean, and ranged from 0.75 to 1.30. The mean value of the Poisson ratios calculated in this study ranged from 0.32 to 0.44 for the 100 to 5000 atom models, respectively.

  5. Modeling of the stress-strain state of the ground mass contaminated with peracetic acid

    Directory of Open Access Journals (Sweden)

    Levenko Anna

    2017-01-01

    Full Text Available None of the methods described previously provides a solution to the problem that deals with the SSS evaluation of the ground mass which is under the influence of chemically active substances and, in particular, under the influence of peracetic acid. The stress-strain state of the ground mass contaminated with peracetic acid was estimated. Stresses occurring in the ground mass in the natural state were determined after the entry of acid into it and after the chemical fixation of it with sodium silicate. All the parameters of the stress-strain state of the ground mass were obtained under a number of physical and mechanical conditions. It was determined that following the work on the silicatization of the ground mass contaminated with peracetic acid the quantity of strain decreased by 26.11 to 48.9%. The comparison of the results of stress calculations indicates the stress reduction in the ground mass in 1.8 – 2.6 times after its fixing.

  6. Influence of the representation models of the stress-strain law on the LMFBR structures in an HCDA

    International Nuclear Information System (INIS)

    Daneri, A.; Toselli, G.; Trombetti, T.; Blanchet, Y.; Louvet, J.; Obry, P.

    1981-08-01

    Most of analysis involved in mechanical calculations related to explosive accidents in fast breeder reactors are now aware of the inadequacy of certain rough stress-strain laws to representing the correct behaviour of vessel materials. Indeed stress waves along the vessel walls deform the material at a high strain rate with multiaxial loading or reverse loading. Recently different questions have been under investigation in France in this direction and the present study, performed in the frame of the agreement CNEN-CEA, is an example of the way how two very important factors (strain rate and strain hardening) may be taken into account in the constitutive equations of materials subject to dynamic deformations. Several parametric calculations have been carried out with the hydrodynamic structural codes ASTARTE-3/4 and SIRIUS, which are the Lagrangian validated code now available at the CNEN and CEA-Cadarache computing centres. Analysis was performed by comparing two reference calculations relating to the MARA 01 and COVA IT7 explosive tests with experimental data and with other calculations in which different values of the initial hardening and of the strain rates of the tank shell material were introduced. In general both codes give similar results; improvements of predicted axial and hoop strains and of impulses in water have been reached in certain cases but it is difficult to find a general trend and there is no ideal constitutive model: indeed the strain rate is not constant in time, in place and in direction and some parts of the vessels are uniaxially loaded while others are multiaxially loaded

  7. Influence of the representation models of the stress-strain law on the LMFBR structures in an HCDA

    International Nuclear Information System (INIS)

    Daneri, A.; Toselli, G.; Trombetti, T.; Blanche, Y.; Louvet, J.; Obry, P.

    1982-01-01

    Most of analysis involved in mechanical calculations related to explosive accidents in fast breeder reactor are now aware of the inadequacy of certain roug stress-strain laws to representing the correct behaviour of vessel materials. Indeed stress waves along the vessel walls deform the material at high strain rate with multiaxial loading or reverse loading. Recently different questions have been under investigation in France in this direction and the present study, performed in the frame of the agreement CNEN-CEA, is an example of the way how two very important factors (strain rate and strain hardening) may be taken into account in the consecutive equations of materials subject to dynamic deformations. Several parametric calculations have been carried out with the hydrodynamic structural codes ASTARTE 3/4 and SIRIUS, which are the Lagrangian validated codes now available at the CNEN and CEA Cadarache Computing Centres.Analysis was performed by comparing two reference calculations relating to the MARA 01 and COVA IT7 explosive tests with experimental data and with other calculations in which different values of the initial hardening and of the strain rates of the tank shell material were introduced. In general both codes give similar results; improvements of predicted axial and hoop strain and of impulses in water have been reached in certain cases but it is difficult to find a general trend and there is no ideal constitutive model: indeed the strain rate is not constant in time, in place and in direction and some parts of the vessels are uniaxially loaded while others are multiaxially loaded

  8. Functional, Responsive Materials Assembled from Recombinant Oleosin

    Science.gov (United States)

    Hammer, Daniel

    Biological cells are surrounded by a plasma membrane made primarily of phospholipids that form a bilayer. This membrane is permselective and compartmentalizes the cell. A simple form of artificial cell is the vesicle, in which a phospholipid bilayer membrane surrounds an aqueous solution. However, there is no a priori reason why a membrane needs to be made of phospholipids. It could be made of any surfactant that forms a bilayer. We have assembled membranes and other structures from the recombinant plant protein oleosin. The ability to assemble from a recombinant protein means that every molecule is identical, we have complete control over the sequence, and hence can build in designer functionality with high fidelity, including adhesion and enzymatic activity. Such incorporation is trivial using the tools of molecular biology. We find that while many variants of oleosin make membranes, others make micelles and sheets. We show how the type of supramolecular structure can be altered by the conditions of solvent, such as ionic strength, and the architecture of the surfactant itself. We show that protease cleavable domains can be incorporated within oleosin, and be engineered to protect other functional domains such as adhesive motifs, to make responsive materials whose activity and shape depend on the action of proteases. We will also present the idea of making ``Franken''-oleosins, where large domains of native oleosin are replaced with domains from other functional proteins, to make hybrids conferred by the donor protein. Thus, we can view oleosin as a template upon which a vast array of designer functionalities can be imparted..

  9. Analysis of Stress Updates in the Material-point Method

    DEFF Research Database (Denmark)

    Andersen, Søren; Andersen, Lars

    2009-01-01

    The material-point method (MPM) is a new numerical method for analysis of large strain engineering problems. The MPM applies a dual formulation, where the state of the problem (mass, stress, strain, velocity etc.) is tracked using a finite set of material points while the governing equations...... are solved on a background computational grid. Several references state, that one of the main advantages of the material-point method is the easy application of complicated material behaviour as the constitutive response is updated individually for each material point. However, as discussed here, the MPM way...

  10. Supplier responsibility for nuclear material quality

    International Nuclear Information System (INIS)

    Stuart, P.S.; Dohna, A.E.

    1976-01-01

    Nuclear materials must be delivered by either the manufacturer or the distributor with objective, documented evidence that the material was manufactured, inspected, and tested by proven techniques performed by qualified personnel working to documented procedures. Measurement devices used for acceptance must be of proven accuracy. The material and all records must be identified for positive traceability as part of the quality history of the nuclear components, system, or structure in which the material was used. In conclusion, the nuclear material supplier must join the fabricator, the installer, and the user in effective implementation of the total systems approach to the application of quality assurance principles to all phases of procurement, fabrication, installation, and use of the safety-related components, systems, and structures in a nuclear power plant

  11. Magnetically responsive biological materials and their applications

    Czech Academy of Sciences Publication Activity Database

    Šafařík, Ivo; Pospíšková, K.; Baldíková, E.; Šafaříková, Miroslava

    2016-01-01

    Roč. 7, č. 4 (2016), s. 254-261 ISSN 0976-3961 Institutional support: RVO:60077344 Keywords : adsorbents * biological materials * carriers * magnetic modification * whole-cell biocatalyst Subject RIV: EI - Biotechnology ; Bionics

  12. Improving the Material Response for Slow Heat of Energetic Materials

    Energy Technology Data Exchange (ETDEWEB)

    Nichols, A L

    2010-03-08

    The goal of modern high explosive slow heat cookoff modeling is to understand the level of mechanical violence. This requires understanding the coupled thermal-mechanical-chemical system that such an environment creates. Recent advances have improved our ability to predict the time to event, and we have been making progress on predicting the mechanical response. By adding surface tension to the product gas pores in the high explosive, we have been able to reduce the current model's tendency to overpressurize confinement vessels. We describe the model and demonstrate how it affects a LX-10 STEX experiment. Issues associated with current product gas equations of state are described and examined.

  13. STRESS-STRAIN STATE IN EMBEDMENT OF REINFORCEMENT IN CASE OF REPEATED LOADINGS

    Directory of Open Access Journals (Sweden)

    Mirsayapov Ilshat Talgatovich

    2016-05-01

    Full Text Available The author offer transforming the diagram of ideal elastic-plastic deformations for the description of the stress-strain state of embedment of reinforcement behind a critical inclined crack at repeatedly repeating loadings. The endurance limit of the adhesion between concrete and reinforcement and its corresponding displacements in case of repeated loadings are accepted as the main indicators. This adhesion law is the most appropriate for the description of physical and mechanical phenomena in the contact zone in case of cyclic loading, because it simply and reliably describes the adhesion mechanism and the nature of the deformation, and greatly simplifies the endurance calculations compared to the standard adhesion law. On the basis of this diagram the author obtained the equations for the description of the distribution of pressures and displacements after cyclic loading with account for the development of deformations of cyclic creep of the concrete under the studs of reinforcement.

  14. The effect of hydrogen on the multiaxial stress-strain behavior of titanium tubing

    International Nuclear Information System (INIS)

    Lentz, C.W.; Hecker, S.S.; Koss, D.A.; Stout, M.G.

    1983-01-01

    The influence of internal hydrogen on the multiaxial stress-strain behavior of commercially pure titanium has been studied. Thin-walled specimens containing either 20 or 1070 ppm hydrogen were tested at constant stress ratios in combined tension and internal pressure. Hydrogen lowers the yield strength but has no significant effect on strain hardening behavior at strains epsilon greater than or equal to 0.02. Thus, hydrogen embrittlement under plain strain or equibiaxial loading is not a consequence of changes of flow behavior. The yielding behavior is described well by Hill's quadratic yield criterion. As measured mechanically and pole figure analysis, the plastic anisotropy changes with deformation in a manner which depends on stress state. A strain dependent, texture-induced strengthening effect in equibiaxial tension an enhanced strain hardening rate

  15. Stress-strain state analysis and optimization of rod system under periodic pulse load

    Directory of Open Access Journals (Sweden)

    Grebenyuk Grigory

    2018-01-01

    Full Text Available The paper considers the problem of analysis and optimization of rod systems subjected to combined static and periodic pulse load. As a result of the study the analysis method was developed based on traditional approach to solving homogeneous matrix equations of state and a special algorithm for developing a particular solution. The influence of pulse parameters variations on stress-strain state of a rod system was analyzed. Algorithms for rod systems optimization were developed basing on strength recalculation and statement and solution of optimization problem as a problem of nonlinear mathematical programming. Recommendations are developed for efficient organization of process for optimization of rod systems under static and periodic pulse load.

  16. Study of the stress-strain state of compressed concrete elements with composite reinforcement

    Directory of Open Access Journals (Sweden)

    Bondarenko Yurii

    2017-01-01

    Full Text Available The efficiency analysis of the application of glass composite reinforcement in compressed concrete elements as a load-carrying component has been performed. The results of experimental studies of the deformation-strength characteristics of this reinforcement on compression and compressed concrete cylinders reinforced by this reinforcement are presented. The results of tests and mechanisms of sample destruction have been analyzed. The numerical analysis of the stress-strain state has been performed for axial compression of concrete elements with glasscomposite reinforcement. The influence of the reinforcement percentage on the stressed state of a concrete compressed element with the noted reinforcement is estimated. On the basis of the obtained results, it is established that the glass-composite reinforcement has positive effect on the strength of the compressed concrete elements. That is, when calculating the load-bearing capacity of such structures, the function of composite reinforcement on compression should not be neglected.

  17. Experimental determination of the stress/strain situation in a sheared tunnel model with canister

    International Nuclear Information System (INIS)

    Pusch, R.

    1978-03-01

    A previous report concerned a technical matter which could be of great importance as regards the mechanical strength of canisters embedded in a bentonite/quartz buffer mass, i.e. the effect of a differential movement triggered by a critical deviatoric stress condition. Even if this is extremely unlikeley to occur it was considered to be of importance to verify the theoretical expressions for the maximum bending moment and maximum shear force. A special reason was to test the hypothesis that the contact pressure would soon reach a high value and then stay fairly constant when the displacement increased. The theoretical approach requires that the stress/strain properties of the fill are thoroghly investigated and described in therms of a mathematical model. Experience shows that this may be a tedions and difficult task. (L.E.)

  18. Variations of fracture toughness and stress-strain curve of cold worked stainless steel and their influence on failure strength of cracked pipe

    International Nuclear Information System (INIS)

    Kamaya, Masayuki

    2016-01-01

    In order to assess failure probability of cracked components, it is important to know the variations of the material properties and their influence on the failure load assessment. In this study, variations of the fracture toughness and stress-strain curve were investigated for cold worked stainless steel. The variations of the 0.2% proof and ultimate strengths obtained using 8 specimens of 20% cold worked stainless steel (CW20) were 77 MPa and 81 MPa, respectively. The respective variations were decreased to 13 and 21 MPa for 40% cold worked material (CW40). Namely, the variation in the tensile strength was decreased by hardening. The COVs (coefficients of variation) of fracture toughness were 7.3% and 16.7% for CW20 and CW40, respectively. Namely, the variation in the fracture toughness was increased by hardening. Then, in order to investigate the influence of the variations in the material properties on failure load of a cracked pipe, flaw assessments were performed for a cracked pipe subjected to a global bending load. Using the obtained material properties led to variation in the failure load. The variation in the failure load of the cracked pipe caused by the variation in the stress-strain curve was less than 1.5% for the COV. The variation in the failure load caused by fracture toughness variation was relatively large for CW40, although it was less than 2.0% for the maximum case. It was concluded that the hardening induced by cold working does not cause significant variation in the failure load of cracked stainless steel pipe. (author)

  19. Multi-Functional Stimuli-Responsive Materials

    Data.gov (United States)

    National Aeronautics and Space Administration — Supramolecular polymers based on non-covalent interactions can display a wide array of stimuli-responsive attributes. They can be tailored to change shape, actuate...

  20. Viscoelastic response of hydrogel materials at finite strains

    OpenAIRE

    Skovly, Martin Johannessen

    2015-01-01

    Hydrogel materials are very soft materials consisting of polymer networks and solvent molecules. The materials may exhibit large volume changes depending on its external chemical and mechanical environment and have viscoelastic properties which is common for many polymeric materials. In order to model the material response with the finite element method, a hydrogel constitutive model have been combined with finite viscoelastic theory and the resulting viscoelastic hydrogel constitutive model ...

  1. Numerical study of the stress-strain state of reinforced plate on an elastic foundation by the Bubnov-Galerkin method

    Science.gov (United States)

    Beskopylny, Alexey; Kadomtseva, Elena; Strelnikov, Grigory

    2017-10-01

    The stress-strain state of a rectangular slab resting on an elastic foundation is considered. The slab material is isotropic. The slab has stiffening ribs that directed parallel to both sides of the plate. Solving equations are obtained for determining the deflection for various mechanical and geometric characteristics of the stiffening ribs which are parallel to different sides of the plate, having different rigidity for bending and torsion. The calculation scheme assumes an orthotropic slab having different cylindrical stiffness in two mutually perpendicular directions parallel to the reinforcing ribs. An elastic foundation is adopted by Winkler model. To determine the deflection the Bubnov-Galerkin method is used. The deflection is taken in the form of an expansion in a series with unknown coefficients by special polynomials, which are a combination of Legendre polynomials.

  2. Life prediction of l6 steel using strain-life curve and cyclic stress-strain curve by means of low cycle fatigue testing

    Science.gov (United States)

    Inamdar, Sanket; Ukhande, Manoj; Date, Prashant; Lomate, Dattaprasad; Takale, Shyam; Singh, RKP

    2017-05-01

    L6 Steel is used as die material in closed die hot forging process. This material is having some unique properties. These properties are due to its composition. Strain softening is the noticeable property of this material. Due to this in spite of cracking at high stress this material gets plastically deformed and encounters loss in time as well as money. Studies of these properties are necessary to nurture this material at fullest extent. In this paper, numerous experiments have been carried on L6 material to evaluate cyclic Stress - strain behavior as swell as strain-life behavior of the material. Low cycle fatigue test is carried out on MTS fatigue test machine at fully reverse loading condition R=-1. Also strain softening effect on forging metal forming process is explained in detail. The failed samples during low cycle fatigue test further investigated metallurgically on scanning electron microscopy. Based on this study, life estimation of hot forging die is carried out and it’s correlation with actual shop floor data is found out. This work also concludes about effect of pre-treatments like nitro-carburizing and surface coating on L6 steel material, to enhance its fatigue life to certain extent.

  3. Materials and society -- Impacts and responsibilities

    Energy Technology Data Exchange (ETDEWEB)

    Westwood, A.R.C.

    1995-11-01

    The needs of today`s advanced societies have moved well beyond the requirements for food and shelter, etc., and now are focused on such concerns as international peace and domestic security, affordable health care, the swift and secure transmission of information, the conservation of resources, and a clean environment. Progress in materials science and engineering is impacting each of these concerns. This paper will present some examples of how this is occurring, and then comment on ethical dilemmas that can arise as a consequence of technological advances. The need for engineers to participate more fully in the development of public policies that help resolve such dilemmas, and so promote the benefits of advancing technology to society, will be discussed.

  4. Effects of mean strain on the random cyclic stress-strain relations of 0Cr18Ni10Ti pipe steel

    International Nuclear Information System (INIS)

    Zhao Yongxiang; Yang Bing

    2005-01-01

    Experimental study is performed for the effects of the mean strain on the random cyclic stress-strain relations of the new nuclear material, 0Cr18Ni10Ti pipe steel. From saving the size of specimens, an improved maximum likelihood fatigue test method is proposed to operate the present strain-controlled fatigue tests. Six straining ratios, -1, -0.52, -0.22, 0.029, 0.18, and 0.48, respectively, are applied to study the effects. Fatigue test has been carried out on totally 104 specimens. The test results reveal that the material exhibits a Masing behaviour and the saturation hysteresis loops under the six ratios hold an entirely relaxation effect of mean stress. There is no effectively method for the description of the mean straining effects under this case. Previous Zhao's random stress-strain relations are therefore applied to characterizing effectively the scattering test data under the six ratios on a basis of Ramberg-Osgood equation. Then the effects of the ratios are analyzed respectively on the average stress amplitudes, the standard deviations of the stress amplitudes, and the stress amplitudes under different survival probabilities and confidences. The results reveal that the ratios act a relatively decreasing effect to the stress amplitudes under higher survival probabilities and confidences. The strongest effect appears at the ratio of 0.029, and a weaker effect acts as the distance increase of the ratio from the zero. In addition, it is indicated that the effects from the sense of average fatigue lives might result in a wrong conclusion. The effects can be appropriately assessed from a probabilistic sense to take into account the scattering regularity of test data and the size of sampling. (author)

  5. A comparative study on the uniaxial mechanical properties of the umbilical vein and umbilical artery using different stress-strain definitions.

    Science.gov (United States)

    Karimi, Alireza; Navidbakhsh, Mahdi

    2014-12-01

    The umbilical cord is part of the fetus and generally includes one umbilical vein (UV) and two umbilical arteries (UAs). As the saphenous vein and UV are the most commonly used veins for the coronary artery disease treatment as a coronary artery bypass graft (CABG), understating the mechanical properties of UV has a key asset in its performance for CABG. However, there is not only a lack of knowledge on the mechanical properties of UV and UA but there is no agreement as to which stress-strain definition should be implemented to measure their mechanical properties. In this study, the UV and UA samples were removed after caesarean from eight individuals and subjected to a series of tensile testing. Three stress definitions (second Piola-Kichhoff stress, engineering stress, and true stress) and four strain definitions (Almansi-Hamel strain, Green-St. Venant strain, engineering strain, and true strain) were employed to determine the linear mechanical properties of UVs and UAs. The nonlinear mechanical behavior of UV/UA was computationally investigated using hyperelastic material models, such as Ogden and Mooney-Rivlin. The results showed that the effect of varying the stress definition on the maximum stress measurements of the UV/UA is significant but not when calculating the elastic modulus. In the true stress-strain diagram, the maximum strain of UV was 92 % higher, while the elastic modulus and maximum stress were 162 and 42 % lower than that of UA. The Mooney-Rivlin material model was designated to represent the nonlinear mechanical behavior of the UV and UA under uniaxial loading.

  6. Analysis of the effects of non-supine sleeping positions on the stress, strain, deformation and intraocular pressure of the human eye

    Science.gov (United States)

    Volpe, Peter A.

    This thesis presents analytical models, finite element models and experimental data to investigate the response of the human eye to loads that can be experienced when in a non-supine sleeping position. The hypothesis being investigated is that non-supine sleeping positions can lead to stress, strain and deformation of the eye as well as changes in intraocular pressure (IOP) that may exacerbate vision loss in individuals who have glaucoma. To investigate the quasi-static changes in stress and internal pressure, a Fluid-Structure Interaction simulation was performed on an axisymmetrical model of an eye. Common Aerospace Engineering methods for analyzing pressure vessels and hyperelastic structural walls are applied to developing a suitable model. The quasi-static pressure increase was used in an iterative code to analyze changes in IOP over time.

  7. Stress-Strain Relation of Tire Rubber Consist of Entangled Polymers, Fillers and Crosslink

    Science.gov (United States)

    Hagita, Katsumi; Bito, Y.; Minagawa, Y.; Omiya, M.; Morita, H.; Doi, M.; Takano, H.

    2009-03-01

    We presented a preliminary result of large scale coarse-grained Molecular Dynamics simulation of filled polymer melts with Sulfur-crosslink under an uni-axial deformation by using the Kremer-Grest Model. The size of simulation box under periodic boundary conditions (PBC) is set to about 66nm to consider length of entangled polymer chains, size and structure of fillers, and non-uniform distribution of crosslink. We put 640 polymer chains of 1024 particles and 32 fillers into the PBC box. Each filler consists of 1280 particles of the C1280 fullerene structure. A repulsive force from the center of the filler is applied to the particles. Here, the particles of the fillers are chosen to be the same as the particles of the polymers and the diameter of the filler is about 15nm. The distribution of the fillers used in this simulation is provided by the result of 2d pattern RMC analysis for 2D-USAXS experiments at SPring-8. Sulfur crosslink are randomly distributed in the system. It is found that stress-strain curves estimated by applying a certain uni-axial deformation to the system in simulations are in good agreement with those in experiments. It is successful to show difference on the S-S curve between existence / absence of fillers and qualitative dependence of attractive force between polymer and filler.

  8. Spherical Nanoindentation Stress-Strain Measurements of BOR-60 14YWT-NFA1 Irradiated Tubes

    Energy Technology Data Exchange (ETDEWEB)

    Weaver, Jordan [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Carvajal Nunez, Ursula [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Krumwiede, David [Univ. of California, Berkeley, CA (United States); Saleh, Tarik A. [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Hosemann, Peter [Univ. of California, Berkeley, CA (United States); Nelson, Andrew Thomas [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Maloy, Stuart Andrew [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Mara, Nathan Allan [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

    2017-09-28

    Spherical nanoindentation stress-strain protocols were applied to characterize unirradiated and fast neutron irradiated nanostructured ferritic alloy (NFA) 14YWT and compared against Berkovich nanohardness and available tensile data. The predicted uniaxial yield strength from spherical, 100 and 5 micron radii, indentation yield strength measurements was 1100-1400 MPa which compares well with the predictions from Berkovich nanohardness, 1200 MPa, and available tensile data, ~1100 MPa. However, spherical indentation measurements predict an increase in the uniaxial yield strength of ~1 GPa while Berkovich nanohardness measurements predict an increase of only ~250 MPa. No tensile data exists on the irradiated condition. It is believed the difference in the predicted uniaxial yield strength between spherical and Berkovich nanoindentation are due to a low number of tests on the irradiated sample combined with the significant heterogeneity in the microstructure, the differences in sensitivity to sample preparation on the irradiated sample between the two indentation protocols , and/or in how strain localizes under the indenter with the possibility of dislocation channeling under Berkovich hardness indents leading to strain softening. Nanoindentation capabilities to test neutron irradiated samples in a radiological area were realized.

  9. Design of Stress-Strain Measuring System for Bulldozing Plate Based on Virtual Instrument Technology

    International Nuclear Information System (INIS)

    Xu, S C; Li, J Q; Zhang, R

    2006-01-01

    Soil is a kind of discrete, multiphase compound that is composed of soil particles, liquid and air. When soil is disturbed by bulldozing plate, the mechanical behavior of the soil will become very complex. Based on the law of action and reaction, the dynamic mechanical behavior of disturbed soil was indirectly analyzed by measuring and studying the forces on the bulldozing plate by soil currently, so a stress-strain virtual measuring system for bulldozing plate, which was designed by the graphical programming language DASYLab, was used to measure the horizontal force Fz acting on the bulldozing plate. In addition, during the course of design, the experimental complexities and the interferential factors influencing on signal logging were analyzed when bulldozing plate worked, so the anti-jamming methods of hardware and software technology were adopted correlatively. In the end, the horizontal force Fz was analyzed with Error Theory, the result shown that the quantificational analysis of Fz were identical to the qualitative results of soil well, and the error of the whole test system is under 5 percent, so the tress-strain virtual measuring system was stable and credible

  10. Developing the multiple stress-strain creep recovery (MS-SCR) test

    Science.gov (United States)

    Elnasri, Mahmoud; Airey, Gordon; Thom, Nick

    2018-04-01

    While most published work from Europe has been concerned with evaluating binders' resistance to rutting based on their stiffness (deformation resistance), work originating in the US has mainly been concerned with ranking binders based on their recoverability in a multiple stress form. This paper details the design of a new modified multiple stress-strain creep recovery (MS-SCR) test. The test is designed to evaluate binders' rutting resistance based on two rutting resistance mechanisms: stiffness and recoverability. A preliminary investigation is presented in this paper followed by details of the design of the new modified test. A 40/60 penetration grade bitumen and bitumen-filler mastics prepared with three filler concentrations (35%, 50%, and 65% filler content by mass of mastic) were tested. In addition, two polymer modified bitumens (PMBs) using the same base bitumen type were examined for validation. Two parameters are introduced to characterise the short and long recovery in the new test. In terms of stiffness, the test allows the behaviour of binders at different stress levels and loading cycles to be studied and produces a new parameter that can quantify the degree of modification. Finally, a relationship between nonlinearity and normal force in the test was investigated.

  11. Fatigue Life Prediction of High Modulus Asphalt Concrete Based on the Local Stress-Strain Method

    Directory of Open Access Journals (Sweden)

    Mulian Zheng

    2017-03-01

    Full Text Available Previously published studies have proposed fatigue life prediction models for dense graded asphalt pavement based on flexural fatigue test. This study focused on the fatigue life prediction of High Modulus Asphalt Concrete (HMAC pavement using the local strain-stress method and direct tension fatigue test. First, the direct tension fatigue test at various strain levels was conducted on HMAC prism samples cut from plate specimens. Afterwards, their true stress-strain loop curves were obtained and modified to develop the strain-fatigue life equation. Then the nominal strain of HMAC course determined using finite element method was converted into local strain using the Neuber method. Finally, based on the established fatigue equation and converted local strain, a method to predict the pavement fatigue crack initiation life was proposed and the fatigue life of a typical HMAC overlay pavement which runs a risk of bottom-up cracking was predicted and validated. Results show that the proposed method was able to produce satisfactory crack initiation life.

  12. Anisotropy effect of the clay soil masses on the stress-strain state of transport tunnels

    Directory of Open Access Journals (Sweden)

    Yushkov Boris Semenovich

    2014-09-01

    Full Text Available The article considers the kinds of clay soil mass anisotropy in the form of the spatial heterogeneity of properties of thawed and frozen soils, ambiguity of the frost heaving values and shrinkage in different directions. The questions of anisotropy of the clay soil properties at the positive temperatures are reported. The dependence of the heterogeneity of the physical and mechanical properties of frozen soils from the cryogenic texture, natural arrangement, different types of stratification and interbedding is considered. Indexes of the strength and strain anisotropy are noted. The accounting possibilities of the basic numerical indexes of heaving phenomena from the standpoint of anisotropy of the properties and processes inherent in the freezing through soil are analyzed by substitution in the heaving strain formula. The unevenness of thawed soil shrinkage in vertical and horizontal directions is noted during the freezing of the top layer. The unevenness of shrinkage in different directions is connected with kind of stress and cryogenic texture. Anisotropy of the frost heaving process is considered in the context of one-dimensional and non-one-dimensional problem depending on the amount of the freezing fronts and their direction. There is summarized the effect of anisotropy appearances on the stress-strain state of the transport tunnel. One can conclude that the resulting non-uniformity of heaving and shrinkage in conjunction with anisotropic properties of frozen soils, is a significant component in the complex of power factors determining the optimal design solution of a transport tunnel.

  13. Study of stress-strain state of pipeline under permafrost conditions

    Science.gov (United States)

    Tarasenko, A. A.; Redutinskiy, M. N.; Chepur, P. V.; Gruchenkova, A. A.

    2018-05-01

    In this paper, the dependences of the stress-strain state and subsidence of pipelines on the dimensions of the subsidence zone are obtained for the sizes of pipes that have become most widespread during the construction of main oil pipelines (530x10, 820x12, 1020x12, 1020x14, 1020x16, 1220x14, 1220x16, 1220x18 mm). True values of stresses in the pipeline wall, as well as the exact location of maximum stresses for the interval of subsidence zones from 5 to 60 meters, are determined. For this purpose, the authors developed a finite element model of the pipeline that takes into account the actual interaction of the pipeline with the subgrade and allows calculating the SSS of the structure for a variable subsidence zone. Based on the obtained dependences for the underground laying of oil pipelines in permafrost areas, it is proposed to artificially limit the zone of possible subsidence by separation supports from the soil with higher building properties and physical-mechanical parameters. This technical solution would significantly reduce costs when constructing new oil pipelines in permafrost areas.

  14. Numerical simulation of stress-strain state of electrophoretic shell molds

    Science.gov (United States)

    Sviridov, A. V.; Odinokov, V. I.; Dmitriev, E. A.; Evstigneev, A. I.; Bashkov, O. V.

    2017-10-01

    In the foundry engineering, castings obtained in one-piece non-gas-generating high-refractory electrophoretic shell molds (ShM) by investment patterns (IP) have an increased rejects percentage associated with low deformation resistance and crack resistance of the SM at different stages of their formation and manufacturing. Crack resistance of the ShM based on IP depends mainly on their stress-strain state (SSS) at various stages of mold forming. SSS decrease significantly improves their crack resistance and decreases their rejects percentage of castings occurring due to clogging and surface defects. In addition, the known methods of decreasing the SSS are still poorly understood. Thus, current research trends are to determine SSS at each stage of ShM forming and develop the ways to decrease it. Theoretical predicting of crack formation in multiple-layer axisymmetric shell molds is given in the work [1], and SSS of multiple-layer axisymmetric shell molds is given in the work [2]. Monolayer electrophoretic ShM had a lack of concern in this field, thus it became an argument for the present workMathematical Model of ShM SSS

  15. Stimuli-Responsive Materials for Controlled Release Applications

    KAUST Repository

    Li, Song

    2015-01-01

    The controlled release of therapeutics has been one of the major challenges for scientists and engineers during the past three decades. To address this outstanding problem, the design and fabrication of stimuli-responsive materials are pursued

  16. 3D Printing of Living Responsive Materials and Devices.

    Science.gov (United States)

    Liu, Xinyue; Yuk, Hyunwoo; Lin, Shaoting; Parada, German Alberto; Tang, Tzu-Chieh; Tham, Eléonore; de la Fuente-Nunez, Cesar; Lu, Timothy K; Zhao, Xuanhe

    2018-01-01

    3D printing has been intensively explored to fabricate customized structures of responsive materials including hydrogels, liquid-crystal elastomers, shape-memory polymers, and aqueous droplets. Herein, a new method and material system capable of 3D-printing hydrogel inks with programed bacterial cells as responsive components into large-scale (3 cm), high-resolution (30 μm) living materials, where the cells can communicate and process signals in a programmable manner, are reported. The design of 3D-printed living materials is guided by quantitative models that account for the responses of programed cells in printed microstructures of hydrogels. Novel living devices are further demonstrated, enabled by 3D printing of programed cells, including logic gates, spatiotemporally responsive patterning, and wearable devices. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  17. Comparative Response of Four Pedogenic Soil Materials to Cement ...

    African Journals Online (AJOL)

    A comparative response of four Pedogenic soil materials to cement stabilization was investigated. The studies focused on the compaction characteristics, the unconfined sompressive strength and the California bearing ratio of the samples. The results obtained show that soil materials from Maiduguri responded favorably to ...

  18. DOE fundamentals handbook: Material science

    International Nuclear Information System (INIS)

    1993-01-01

    This handbook was developed to assist nuclear facility operating contractors in providing operators, maintenance personnel, and the technical staff with the necessary fundamentals training to ensure a basic understanding of the structure and properties of metals. This volume contains the two modules: structure of metals (bonding, common lattic types, grain structure/boundary, polymorphis, alloys, imperfections in metals) and properties of metals (stress, strain, Young modulus, stress-strain relation, physical properties, working of metals, corrosion, hydrogen embrittlement, tritium/material compatibility)

  19. Temperature- and light-responsive smart polymer materials.

    Science.gov (United States)

    Jochum, Florian D; Theato, Patrick

    2013-09-07

    Stimuli-responsive polymers have been attracting great interest within the scientific community for several decades. The unique feature to respond to small changes in the environmental conditions has made this class of materials very promising for several applications in the field of nanoscience, nanotechnology and nanomedicine. So far, several different chemical, physical or biochemical stimuli have been investigated within natural or synthetic polymers. Very interesting and appealing seems to be the combination of several stimuli to tune the properties of these materials in manifold ways. Within this present review, we want to highlight the recent progress in the field of synthetic stimuli-responsive polymers combining temperature and light responsiveness.

  20. Determination of parameters for a stress-strain constitutive equation considering time-dependent behavior of Toki granite

    International Nuclear Information System (INIS)

    Hirano, Toru; Seno, Yasuhiro; Nakama, Shigeo; Okubo, Seisuke

    2008-01-01

    Toki granite was tested to obtain parameters for the constitutive equation. The testing method was uniaxial compressive loading at the moderate a constant strain rate that is decreased after yielding to obtain the complete stress-strain curve. In addition, two kinds of the strain rate were alternately switched to obtain the parameter n from one specimen. The n represents the strength time-dependence in the constitutive equation. The second parameter m can be obtained by fitting the experimental stress-strain curve to the calculated curve. The m accounts for the behavior after yielding. According to the results, Toki granite has n=52 and m=60, showing relatively weak time-dependence of creep failure. (author)

  1. The Stress-Strain State of Recent Structures in the Northeastern Sector of the Russian Arctic Region

    Science.gov (United States)

    Imaeva, L. P.; Imaev, V. S.; Mel'nikova, V. I.

    2018-03-01

    Complex research to determine the stress-strain state of the Earth's crust and the types of seismotectonic destruction for the northeastern sector of the Russian Arctic was conducted. The principles of regional ranking of neotectonic structures were developed according to the activity of geodynamic processes, and argumentation for their class differentiation is presented. The structural-tectonic position, the parameters of the deep structure, the system of active faults, and the tectonic stress fields, calculated on the basis of both tectonophysical analysis of discontinuous and folded late Cenozoic deformations and seismological data, were analyzed. This complex of investigations made it possible to determine the directions of the main axes of deformations of the stress-strain state of the Earth's crust and to reveal the regularity in the change of tectonic regimes.

  2. Stress-strain effects on powder-in-tube MgB2 tapes and wires

    International Nuclear Information System (INIS)

    Katagiri, Kazumune; Takaya, Ryuya; Kasaba, Koichi; Tachikawa, Kyoji; Yamada, Yutaka; Shimura, Satoshi; Koshizuka, Naoki; Watanabe, Kazuo

    2005-01-01

    The effects of stress-strain on the critical current, I c , of ex situ powder-in-tube (PIT)-processed Ni-sheathed MgB 2 tapes and round wires as well as in situ PIT-processed Cu-sheathed wires at 4.2 K in a magnetic field up to 5 T have been studied. The effect of In powder addition on the Ni-sheathed MgB 2 wire was not so clear compared with that in the tape, in which the irreversible strain, ε irr , for the I c degradation onset increases significantly by the addition. This is attributed to the difference in the microstructure of the core associated with cold workings. A peak and gradual degradation behaviour of I c with strain beyond ε irr was found in the wire, whereas no evident peak and a steep degradation behaviour was found in the tape. As a possible reason, the difference in the triaxial residual stress state at 4.2 K due to the difference in geometry of the cross-section is suspected. The transverse compression tests revealed that I c of the wire did not degrade up to 270 MPa. Again, the effect of In addition was minimal. The Young's modulus of MgB 2 , 31-41 GPa, at room temperature was estimated by a tensile test of Cu sheath wire using a high-accuracy extensometer and the law of mixtures. The tensile strain dependence of I c in the Cu sheath wire was similar to that in the Ni-sheathed wire, ε irr being 0.4%. However, the stress corresponding to ε irr , 50 MPa, was about 1/10 of that for the Ni-sheath wire and the irreversible transverse compressive stress, 150 MPa, was also lower. The effect of bending strain on the I c in Cu-sheathed wire was compared with that of the tensile strain

  3. Stimuli-Responsive Materials for Controlled Release Applications

    KAUST Repository

    Li, Song

    2015-04-01

    The controlled release of therapeutics has been one of the major challenges for scientists and engineers during the past three decades. To address this outstanding problem, the design and fabrication of stimuli-responsive materials are pursued to guarantee the controlled release of cargo at a specific time and with an accurate amount. Upon applying different stimuli such as light, magnetic field, heat, pH change, enzymes or redox, functional materials change their physicochemical properties through physical transformation or chemical reactions, allowing the release of payload agents on demand. This dissertation studied three stimuli-responsive membrane systems for controlled release from films of macro sizes to microcapsules of nano sizes. The first membrane system is a polymeric composite film which can decrease and sustain diffusion upon light irradiation. The photo-response of membranes is based on the photoreaction of cinnamic derivatives. The second one is composite membrane which can improve diffusion upon heating. The thermo-response of membranes comes from the volume phase transition ability of hydrogels. The third one is microcapsule which can release encapsulated agents upon light irradiation. The photo-response of capsules results from the photoreaction of nitrobenzyl derivatives. The study on these membrane systems reveals that stimuli-responsive release can be achieved by utilizing different functional materials on either macro or micro level. Based on the abundant family of smart materials, designing and fabricating stimuli-responsive systems shall lead to various advanced release processes on demand for biomedical applications.

  4. Stress overshoot in stress-strain curves of Zr65Al10Ni10Cu15 metallic glass

    International Nuclear Information System (INIS)

    Kawamura, Y.; Shibata, T.; Inoue, A.; Masumoto, T.

    1997-01-01

    The essential features of the stress overshoot in the stress-strain curves of Zr 65 Al 10 Ni 10 Cu 15 (at.%) metallic glass that has a wide supercooled liquid region were revealed. The stress overshoot was dependent on temperature, strain rate, and stress relaxation. During the stretch, a change in strain rate gave rise to stress overshoot or undershoot which was sensitive to the variable quantities in the strain rate. copyright 1997 American Institute of Physics

  5. The influence of material properties on plastic hinge rotational capacity and strength

    NARCIS (Netherlands)

    Steenbergen, H.M.G.M.; Bijlaard, F.S.K.; Daniels, B.J.

    1996-01-01

    In this article the effects of standardised material stress-strain behaviours on plastic hinge length, moment and rotational capacity are investigated using a specially developed computer program. Material properties are described using three standard post-yield stress-strain characteristics, as

  6. Development and Application of a Tool for Optimizing Composite Matrix Viscoplastic Material Parameters

    Science.gov (United States)

    Murthy, Pappu L. N.; Naghipour Ghezeljeh, Paria; Bednarcyk, Brett A.

    2018-01-01

    This document describes a recently developed analysis tool that enhances the resident capabilities of the Micromechanics Analysis Code with the Generalized Method of Cells (MAC/GMC) and its application. MAC/GMC is a composite material and laminate analysis software package developed at NASA Glenn Research Center. The primary focus of the current effort is to provide a graphical user interface (GUI) capability that helps users optimize highly nonlinear viscoplastic constitutive law parameters by fitting experimentally observed/measured stress-strain responses under various thermo-mechanical conditions for braided composites. The tool has been developed utilizing the MATrix LABoratory (MATLAB) (The Mathworks, Inc., Natick, MA) programming language. Illustrative examples shown are for a specific braided composite system wherein the matrix viscoplastic behavior is represented by a constitutive law described by seven parameters. The tool is general enough to fit any number of experimentally observed stress-strain responses of the material. The number of parameters to be optimized, as well as the importance given to each stress-strain response, are user choice. Three different optimization algorithms are included: (1) Optimization based on gradient method, (2) Genetic algorithm (GA) based optimization and (3) Particle Swarm Optimization (PSO). The user can mix and match the three algorithms. For example, one can start optimization with either 2 or 3 and then use the optimized solution to further fine tune with approach 1. The secondary focus of this paper is to demonstrate the application of this tool to optimize/calibrate parameters for a nonlinear viscoplastic matrix to predict stress-strain curves (for constituent and composite levels) at different rates, temperatures and/or loading conditions utilizing the Generalized Method of Cells. After preliminary validation of the tool through comparison with experimental results, a detailed virtual parametric study is

  7. A Modified Johnson-Cook Model for Sheet Metal Forming at Elevated Temperatures and Its Application for Cooled Stress-Strain Curve and Spring-Back Prediction

    International Nuclear Information System (INIS)

    Duc-Toan, Nguyen; Tien-Long, Banh; Young-Suk, Kim; Dong-Won, Jung

    2011-01-01

    In this study, a modified Johnson-Cook (J-C) model and an innovated method to determine (J-C) material parameters are proposed to predict more correctly stress-strain curve for tensile tests in elevated temperatures. A MATLAB tool is used to determine material parameters by fitting a curve to follow Ludwick's hardening law at various elevated temperatures. Those hardening law parameters are then utilized to determine modified (J-C) model material parameters. The modified (J-C) model shows the better prediction compared to the conventional one. As the first verification, an FEM tensile test simulation based on the isotropic hardening model for boron sheet steel at elevated temperatures was carried out via a user-material subroutine, using an explicit finite element code, and compared with the measurements. The temperature decrease of all elements due to the air cooling process was then calculated when considering the modified (J-C) model and coded to VUMAT subroutine for tensile test simulation of cooling process. The modified (J-C) model showed the good agreement between the simulation results and the corresponding experiments. The second investigation was applied for V-bending spring-back prediction of magnesium alloy sheets at elevated temperatures. Here, the combination of proposed J-C model with modified hardening law considering the unusual plastic behaviour for magnesium alloy sheet was adopted for FEM simulation of V-bending spring-back prediction and shown the good comparability with corresponding experiments.

  8. Mathematical Modeling in Systems for Operational Evaluation of the Stress-Strain State of the Arch-Gravity Dam at the Sayano-Shushenskaya Hydroelectric Power Plant

    Energy Technology Data Exchange (ETDEWEB)

    Bellendir, E. N.; Gordon, L. A., E-mail: lev-gordon@mail.ru; Khrapkov, A. A.; Skvortsova, A. E., E-mail: SkvortsovaAE@vniig.ru [B. E. Vedeneev All-Russia Research Institute of Hydraulic Engineering (VNIIG) (Russian Federation)

    2017-01-15

    Current studies of the stress-strain state of the dam at the Sayano-Shushenskaya Hydroelectric Power Plant at VNIIG based on mathematical modeling including full scale and experimental data are described. Applications and programs intended for automatic operational evaluation of the stress-strain state of the dam for optimizing control of the upper race level in the course of the annual filling-drawdown cycle and during seismic events are examined. Improvements in systems for monitoring the stress-strain state of concrete dams are proposed.

  9. Emergency preparedness and response in transport of radioactive material

    International Nuclear Information System (INIS)

    Takani, Michio

    2008-01-01

    Nuclear power has been providing clean, affordable electricity in many parts of the world for nearly half a century. The national and international transport of nuclear fuel cycle materials is essential to support this activity. To sustain the nuclear power industry, fuel cycle materials have to be transported safely and efficiently. The nature of the industry is such that most countries with large-scale nuclear power industries cannot provide all the necessary fuel services themselves and consequently nuclear fuel cycle transport activities are international. The radioactive material transport industry has an outstanding safety record spanning over 45 years; however the transport of radioactive materials cannot and most not be taken for granted. Efficient emergency preparedness and response in the transport of radioactive material is an important element to ensure the maximum safety in accident conditions. The World Nuclear Transport Institute (WNTI), founded by International Nuclear Services (INS) of the United Kingdom, AREVA of France an the Federation of Electric Power Companies (FEPC) of Japan, represents the collective interest of the radioactive material transport sector, and those who rely on safe, effective and reliable transport. As part of its activities, WNTI has conducted two surveys through its members on emergency preparedness and response in the transport of radioactive material and emergency exercises. After recalling the International Atomic Energy Agency approach on emergency response, this paper will be discussing the main conclusion of surveys, in particular the national variations in emergency response and preparedness on the national and local levels of regulations, the emergency preparedness in place, the emergency response organisation (who and how), communication and exercises. (author)

  10. First response to transportation emergencies involving radioactive materials

    International Nuclear Information System (INIS)

    1994-01-01

    This FEMA/DOE/DOT videocourse describes the basis for procedures to be used by emergency first responders for transportation accidents which involve radioactive materials. Various commercial and government sector radioactive materials shipment programs will be described and will include information about hazards and the elements of safety, proper first response actions, notification procedures, and state or federal assistance during emergencies. Primary audience: fire service and emergency management personnel

  11. PROCESS FEATURES OF FLUCTUATIONS PROPAGATION AT STRESS-STRAIN WORK OF THE RAILWAY TRACK

    Directory of Open Access Journals (Sweden)

    I. O. Bondarenko

    2015-12-01

    reliability of trains as part of security checkpoints in the area of rolling stock gauge because of its technical state. Therefore, for examining issues of reliable performance elements of the permanent way and substructures of the railway track are proposed its stress-strain work. It gives the possibility to consider a dynamic process, localized both in time and space.

  12. Emergency response arrangements for the transport of radioactive materials

    International Nuclear Information System (INIS)

    Morgan-Warren, E.

    2004-01-01

    Response arrangements are required for the transport of radioactive materials, under both transport and health and safety legislation, to safeguard persons, property and the environment in the event of incidents and emergencies. Responsibilities fall on both government and industry: government is responsible for ensuring public safety and providing information and reassurance. This responsibility is discharged for each type of incident by a nominated ''lead department'', supported as appropriate by other government departments and agencies; for their part, operators are obliged to have arrangements in place for dealing with the practicalities of any reasonably foreseeable incident, including recovery and onward transport of a package, and any required clean-up or restoration of the environment. This paper outlines both the government and industry arrangements in Great Britain. The principles of response and intervention are discussed, together with the lead department concept, regulatory requirements, and the plans developed by the transport industry to ensure a nation-wide response capability

  13. Shape-Morphing Materials from Stimuli-Responsive Hydrogel Hybrids.

    Science.gov (United States)

    Jeon, Seog-Jin; Hauser, Adam W; Hayward, Ryan C

    2017-02-21

    The formation of well-defined and functional three-dimensional (3D) structures by buckling of thin sheets subjected to spatially nonuniform stresses is common in biological morphogenesis and has become a subject of great interest in synthetic systems, as such programmable shape-morphing materials hold promise in areas including drug delivery, biomedical devices, soft robotics, and biomimetic systems. Given their ability to undergo large changes in swelling in response to a wide variety of stimuli, hydrogels have naturally emerged as a key type of material in this field. Of particular interest are hybrid systems containing rigid inclusions that can define both the anisotropy and spatial nonuniformity of swelling as well as nanoparticulate additives that can enhance the responsiveness and functionality of the material. In this Account, we discuss recent progress in approaches to achieve well-defined shape morphing in hydrogel hybrids. First, we provide an overview of materials and methods that facilitate fabrication of such systems and outline the geometry and mechanics behind shape morphing of thin sheets. We then discuss how patterning of stiff inclusions within soft responsive hydrogels can be used to program both bending and swelling, thereby providing access to a wide array of complex 3D forms. The use of discretely patterned stiff regions to provide an effective composite response offers distinct advantages in terms of scalability and ease of fabrication compared with approaches based on smooth gradients within a single layer of responsive material. We discuss a number of recent advances wherein control of the mechanical properties and geometric characteristics of patterned stiff elements enables the formation of 3D shapes, including origami-inspired structures, concatenated helical frameworks, and surfaces with nonzero Gaussian curvature. Next, we outline how the inclusion of functional elements such as nanoparticles can enable unique pathways to programmable

  14. Optical response of the FXG solution to different phantom materials

    International Nuclear Information System (INIS)

    Cavinato, C.C.; Sakuraba, R.K.; Cruz, J.C.; Campos, L.L.

    2011-01-01

    The purpose of this work is to evaluate the performance of the Fricke xylenol gel (FXG) solution developed at IPEN, prepared with 270 Bloom gelatine (made in Brazil), for clinical electron beams to the reference depth, using different phantom materials. The colour change, optical absorption spectra, intra and inter-batches reproducibility, dose-response, lower detection limit, energy and dose rate dependent response and response uniformity were studied. The excellent results obtained indicate the viability of employing this solution in 2D spectrophotometric dosimetry (could be extended to 3D MRI dosimetry) to be applied in quality assurance for clinical radiotherapy treatment planning of superficial tumours being treated with clinical electron beams.

  15. Nutritional response of Okra to various packaging materials and ...

    African Journals Online (AJOL)

    The research is focused at determining the nutritional response of Okra when pickling is carried out using different antimicrobial liquids (vinegar, olive oil, and groundnut oil) and packaging materials (glass jar, plastic and stainless steel), as well as make a comparism when spices (garlic, ginger, mixture of garlic and ginger) ...

  16. NUMERICAL ANALYSIS OF THE STRESS-STRAIN STATE OF A ROPE STRAND WITH LINEAR CONTACT UNDER TENSION AND TORSION LOADING CONDITIONS

    Directory of Open Access Journals (Sweden)

    Evgenij Kalentev

    2017-06-01

    Full Text Available The paper presents the results of a numerical analysis of the stress-strain state of a rope strand with linear contact under tension and torsion loading conditions. Calculations are done using the ANSYS software package. Different approaches to calculation of the stress-strain state of ropes are reviewed, and their advantages and deficiencies are considered. The analysis of the obtained results leads us to the conclusion that the proposed method can be used in engineering calculations.

  17. Ontario Hydro's transportation of radioactive material and emergency response plan

    International Nuclear Information System (INIS)

    Karmali, N.

    1993-01-01

    Ontario Hydro has been transporting radioactive material for almost 30 years without any exposure to the public or release to the environment. However, there have been three accidents involving Hydro's shipments of radioactive material. In addition to the quality packaging and shipping program, Ontario Hydro has an Emergency Response Plan and capability to deal with an accident involving a shipment of radioactive material. The Corporation's ability to respond, to effectively control and contain the situation, site remediation, and to provide emergency public information in the event of a road accident minimizes the risk to the public and the environment. This emphasizes their commitment to worker safety, public safety and impact to the environment. Response capability is mandated under various legislation and regulations in Canada

  18. Construction of long-term isochronous stress-strain curves by a modeling of short-term creep curves for a Grade 9Cr-1Mo steel

    International Nuclear Information System (INIS)

    Kim, Woo-Gon; Yin, Song-Nan; Koo, Gyeong-Hoi

    2009-01-01

    This study dealt with the construction of long-term isochronous stress-strain curves (ISSC) by a modeling of short-term creep curves for a Grade 9Cr-1Mo steel (G91) which is a candidate material for structural applications in the next generation nuclear reactors as well as in fusion reactors. To do this, tensile material data used in the inelastic constitutive equations was obtained by tensile tests at 550degC. Creep curves were obtained by a series of creep tests with different stress levels of 300MPa to 220MPa at an identical controlled temperature of 550degC. On the basis of these experimental data, the creep curves were characterized by Garofalo's creep model. Three parameters of P 1 , P 2 and P 3 in Garofalo's model were properly optimized by a nonlinear least square fitting (NLSF) analysis. The stress dependency of the three parameters was found to be a linear relationship. But, the P 3 parameter representing the steady state creep rate exhibited a two slope behavior with different stress exponents at a transient stress of about 250 MPa. The long-term creep curves of the G91 steel was modeled by Garofalo's model with only a few short-term creep data. Using the modeled creep curves, the long-term isochronous curves up to 10 5 hours were successfully constructed. (author)

  19. Computational methods for coupling microstructural and micromechanical materials response simulations

    Energy Technology Data Exchange (ETDEWEB)

    HOLM,ELIZABETH A.; BATTAILE,CORBETT C.; BUCHHEIT,THOMAS E.; FANG,HUEI ELIOT; RINTOUL,MARK DANIEL; VEDULA,VENKATA R.; GLASS,S. JILL; KNOROVSKY,GERALD A.; NEILSEN,MICHAEL K.; WELLMAN,GERALD W.; SULSKY,DEBORAH; SHEN,YU-LIN; SCHREYER,H. BUCK

    2000-04-01

    Computational materials simulations have traditionally focused on individual phenomena: grain growth, crack propagation, plastic flow, etc. However, real materials behavior results from a complex interplay between phenomena. In this project, the authors explored methods for coupling mesoscale simulations of microstructural evolution and micromechanical response. In one case, massively parallel (MP) simulations for grain evolution and microcracking in alumina stronglink materials were dynamically coupled. In the other, codes for domain coarsening and plastic deformation in CuSi braze alloys were iteratively linked. this program provided the first comparison of two promising ways to integrate mesoscale computer codes. Coupled microstructural/micromechanical codes were applied to experimentally observed microstructures for the first time. In addition to the coupled codes, this project developed a suite of new computational capabilities (PARGRAIN, GLAD, OOF, MPM, polycrystal plasticity, front tracking). The problem of plasticity length scale in continuum calculations was recognized and a solution strategy was developed. The simulations were experimentally validated on stockpile materials.

  20. Autonomic composite hydrogels by reactive printing: materials and oscillatory response.

    Science.gov (United States)

    Kramb, R C; Buskohl, P R; Slone, C; Smith, M L; Vaia, R A

    2014-03-07

    Autonomic materials are those that automatically respond to a change in environmental conditions, such as temperature or chemical composition. While such materials hold incredible potential for a wide range of uses, their implementation is limited by the small number of fully-developed material systems. To broaden the number of available systems, we have developed a post-functionalization technique where a reactive Ru catalyst ink is printed onto a non-responsive polymer substrate. Using a succinimide-amine coupling reaction, patterns are printed onto co-polymer or biomacromolecular films containing primary amine functionality, such as polyacrylamide (PAAm) or poly-N-isopropyl acrylamide (PNIPAAm) copolymerized with poly-N-(3-Aminopropyl)methacrylamide (PAPMAAm). When the films are placed in the Belousov-Zhabotinsky (BZ) solution medium, the reaction takes place only inside the printed nodes. In comparison to alternative BZ systems, where Ru-containing monomers are copolymerized with base monomers, reactive printing provides facile tuning of a range of hydrogel compositions, as well as enabling the formation of mechanically robust composite monoliths. The autonomic response of the printed nodes is similar for all matrices in the BZ solution concentrations examined, where the period of oscillation decreases in response to increasing sodium bromate or nitric acid concentration. A temperature increase reduces the period of oscillations and temperature gradients are shown to function as pace-makers, dictating the direction of the autonomic response (chemical waves).

  1. Stress-Strain state of structural elements of LWR fuel rods modeling in the MSC.MARC and ANSYS software

    International Nuclear Information System (INIS)

    Kuznetsov, A.; Kuznetsov, V.; Krupkin, A.; Kashirin, B.; Medvedev, A.; Novikov, V.

    2009-01-01

    The results of stress-strain state in the fuel rod spring fixing lock coils modeling are presented in this paper. The solution of this problem was realized in finite-element software MSC.MARC and ANSIS. The solution was obtained in the three-dimensional setting, taking into account multicontact interaction and all physical and geometric nonlinearities. The finite-element models were verified on analytical parities and experimental data. Results of verification have proved a correctness of the accepted finite-element models

  2. Nanotechnology, neuromodulation & the immune response: discourse, materiality & ethics.

    Science.gov (United States)

    Fins, Joseph J

    2015-04-01

    Drawing upon the American Pragmatic tradition in philosophy and the more recent work of philosopher Karen Barad, this paper examines how scientific problems are both obscured, and resolved by our use of language describing the natural world. Using the example of the immune response engendered by neural implants inserted in the brain, the author explains how this discourse has been altered by the advent of nanotechnology methods and devices which offer putative remedies that might temper the immune response in the central nervous system. This emergent nanotechnology has altered this problem space and catalyzed one scientific community to acknowledge a material reality that was always present, if not fully acknowledged.

  3. Emergency response planning for transport accidents involving radioactive materials

    International Nuclear Information System (INIS)

    1982-03-01

    The document presents a basic discussion of the various aspects and philosophies of emergency planning and preparedness along with a consideration of the problems which might be encountered in a transportation accident involving a release of radioactive materials. Readers who are responsible for preparing emergency plans and procedures will have to decide on how best to apply this guidance to their own organizational structures and will also have to decide on an emergency planning and preparedness philosophy suitable to their own situations

  4. Solar Sail Material Performance Property Response to Space Environmental Effects

    Science.gov (United States)

    Edwards, David L.; Semmel, Charles; Hovater, Mary; Nehls, Mary; Gray, Perry; Hubbs, Whitney; Wertz, George

    2004-01-01

    The National Aeronautics and Space Administration's (NASA) Marshall Space Flight Center (MSFC) continues research into the utilization of photonic materials for spacecraft propulsion. Spacecraft propulsion, using photonic materials, will be achieved using a solar sail. A solar sail operates on the principle that photons, originating from the sun, impart pressure to the sail and therefore provide a source for spacecraft propulsion. The pressure imparted to a solar sail can be increased, up to a factor of two, if the sun-facing surface is perfectly reflective. Therefore, these solar sails are generally composed of a highly reflective metallic sun-facing layer, a thin polymeric substrate and occasionally a highly emissive back surface. Near term solar sail propelled science missions are targeting the Lagrange point 1 (Ll) as well as locations sunward of L1 as destinations. These near term missions include the Solar Polar Imager and the L1 Diamond. The Environmental Effects Group at NASA s Marshall Space Flight Center (MSFC) continues to actively characterize solar sail material in preparation for these near term solar sail missions. Previous investigations indicated that space environmental effects on sail material thermo-optical properties were minimal and would not significantly affect the propulsion efficiency of the sail. These investigations also indicated that the sail material mechanical stability degrades with increasing radiation exposure. This paper will further quantify the effect of space environmental exposure on the mechanical properties of candidate sail materials. Candidate sail materials for these missions include Aluminum coated Mylar[TM], Teonex[TM], and CPl (Colorless Polyimide). These materials were subjected to uniform radiation doses of electrons and protons in individual exposures sequences. Dose values ranged from 100 Mrads to over 5 Grads. The engineering performance property responses of thermo-optical and mechanical properties were

  5. First-principles studies on the pressure dependences of the stress-strain relationship and elastic stability of semiconductors

    International Nuclear Information System (INIS)

    Wang, S Q; Ye, H Q; Yip, S

    2006-01-01

    We investigate the stress-strain relationship and elastic stability of zinc-blende GaP, GaN, InP and BN lattices under hydrostatic pressure by first-principles calculation. A simple and direct ab initio implementation for studying the mechanical properties of cubic crystals is developed. The four phases' full-set stress-strain coefficients in wide pressure ranges are theoretically calculated. The fundamental mechanism of elastic stability and the origin of phase transformation under hydrostatic pressure are explored. We found that the abilities for most of these lattices are enhanced to sustain axial strain but weaken to shear strain under higher pressure. The conditions of lattice stability are analysed using both the thermodynamic work-energy criterion and the elastic-stiffness criteria. We show that the lattice collapse of the perfect crystals is caused by the disappearance of their bulk moduli under volume dilation. Lattice defects are considered to be the main reason causing phase transformation under pressure. The correlation between the phonon softening and the variation of elastic coefficients is studied. The pressure dependence of the Kleinman internal strain parameter and its relationship to elastic stability is also explored

  6. Emergency response arrangements for the transport of radioactive materials

    Energy Technology Data Exchange (ETDEWEB)

    Morgan-Warren, E. [Radioactive Materials Transport Div., Dept. for Transport, London (United Kingdom)

    2004-07-01

    Response arrangements are required for the transport of radioactive materials, under both transport and health and safety legislation, to safeguard persons, property and the environment in the event of incidents and emergencies. Responsibilities fall on both government and industry: government is responsible for ensuring public safety and providing information and reassurance. This responsibility is discharged for each type of incident by a nominated ''lead department'', supported as appropriate by other government departments and agencies; for their part, operators are obliged to have arrangements in place for dealing with the practicalities of any reasonably foreseeable incident, including recovery and onward transport of a package, and any required clean-up or restoration of the environment. This paper outlines both the government and industry arrangements in Great Britain. The principles of response and intervention are discussed, together with the lead department concept, regulatory requirements, and the plans developed by the transport industry to ensure a nation-wide response capability.

  7. Structural health monitoring in composite materials using frequency response methods

    Science.gov (United States)

    Kessler, Seth S.; Spearing, S. Mark; Atalla, Mauro J.; Cesnik, Carlos E. S.; Soutis, Constantinos

    2001-08-01

    Cost effective and reliable damage detection is critical for the utilization of composite materials in structural applications. Non-destructive evaluation techniques (e.g. ultrasound, radiography, infra-red imaging) are available for use during standard repair and maintenance cycles, however by comparison to the techniques used for metals these are relatively expensive and time consuming. This paper presents part of an experimental and analytical survey of candidate methods for the detection of damage in composite materials. The experimental results are presented for the application of modal analysis techniques applied to rectangular laminated graphite/epoxy specimens containing representative damage modes, including delamination, transverse ply cracks and through-holes. Changes in natural frequencies and modes were then found using a scanning laser vibrometer, and 2-D finite element models were created for comparison with the experimental results. The models accurately predicted the response of the specimems at low frequencies, but the local excitation and coalescence of higher frequency modes make mode-dependent damage detection difficult and most likely impractical for structural applications. The frequency response method was found to be reliable for detecting even small amounts of damage in a simple composite structure, however the potentially important information about damage type, size, location and orientation were lost using this method since several combinations of these variables can yield identical response signatures.

  8. Hazardous Materials Management and Emergency Response training Center needs assessment

    International Nuclear Information System (INIS)

    McGinnis, K.A.; Bolton, P.A.; Robinson, R.K.

    1993-09-01

    For the Hanford Site to provide high-quality training using simulated job-site situations to prepare the 4,000 Site workers and 500 emergency responders for known and unknown hazards a Hazardous Materials Management and Emergency Response Training Center is needed. The center will focus on providing classroom lecture as well as hands-on, realistic training. The establishment of the center will create a partnership among the US Department of Energy; its contractors; labor; local, state, and tribal governments; and Xavier and Tulane Universities of Louisiana. This report presents the background, history, need, benefits, and associated costs of the proposed center

  9. The MIDAS touch for Accurately Predicting the Stress-Strain Behavior of Tantalum

    Energy Technology Data Exchange (ETDEWEB)

    Jorgensen, S. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)

    2016-03-02

    Testing the behavior of metals in extreme environments is not always feasible, so material scientists use models to try and predict the behavior. To achieve accurate results it is necessary to use the appropriate model and material-specific parameters. This research evaluated the performance of six material models available in the MIDAS database [1] to determine at which temperatures and strain-rates they perform best, and to determine to which experimental data their parameters were optimized. Additionally, parameters were optimized for the Johnson-Cook model using experimental data from Lassila et al [2].

  10. Use of inelastic analysis to determine the response of packages to puncture accidents

    International Nuclear Information System (INIS)

    Ammerman, D.J.; Ludwigsen, J.S.

    1996-01-01

    The accurate analytical determination of the response of radioactive material transportation packages to the hypothetical puncture accident requires inelastic analysis techniques. Use of this improved analysis method recudes the reliance on empirical and approximate methods to determine the safety for puncture accidents. This paper will discuss how inelastic analysis techniques can be used to determine the stresses, strains and deformations resulting from puncture accidents for thin skin materials with different backing materials. A method will be discussed to assure safety for all of these types of packages

  11. Extracting Stress-Strain and Compressive Yield Stress Information from Spherical Indentation

    National Research Council Canada - National Science Library

    Juliano, Thomas F; VanLandingham, Mark R; Weerasooriya, Tusit; Moy, Paul

    2007-01-01

    ...) are compared to bulk mechanical test data for a number of materials important for U.S. Army applications, including polycarbonate, polymethymethacrylate, a tungsten carbide ceramic composite (WC with 11.6% Cobalt...

  12. Acquirement of true stress-strain curve using true fracture strain obtained by tensile test and FE analysis

    International Nuclear Information System (INIS)

    Lee, Kyoung Yoon; Kim, Tae Hyung; Lee, Hyung Yil

    2009-01-01

    In this work, we predict a true fracture strain using load-displacement curves from tensile test and Finite Element Analysis (FEA), and suggest a method for acquiring true Stress-Strain (SS) curves by predicted fracture strain. We first derived the true SS curve up to necking point from load-displacement curve. As the beginning, the posterior necking part of true SS curve is linearly extrapolated with the slope at necking point. The whole SS curve is then adopted for FE simulation of tensile test. The Bridgman factor or suitable plate correction factors are applied to pre and post FEA. In the load-true strain curve from FEA, the true fracture strain is determined as the matching point to test fracture load. The determined true strain is validated by comparing with test fracture strain. Finally, we complete the true SS curve by combining the prior necking part and linear part, the latter of which connects necking and predicted fracture points.

  13. Acquirement of true stress-strain curve using true fracture strain obtained by tensile test and FE analysis

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Kyoung Yoon; Kim, Tae Hyung; Lee, Hyung Yil [Sogang University, Seoul (Korea, Republic of)

    2009-07-01

    In this work, we predict a true fracture strain using load-displacement curves from tensile test and Finite Element Analysis (FEA), and suggest a method for acquiring true Stress-Strain (SS) curves by predicted fracture strain. We first derived the true SS curve up to necking point from load-displacement curve. As the beginning, the posterior necking part of true SS curve is linearly extrapolated with the slope at necking point. The whole SS curve is then adopted for FE simulation of tensile test. The Bridgman factor or suitable plate correction factors are applied to pre and post FEA. In the load-true strain curve from FEA, the true fracture strain is determined as the matching point to test fracture load. The determined true strain is validated by comparing with test fracture strain. Finally, we complete the true SS curve by combining the prior necking part and linear part, the latter of which connects necking and predicted fracture points.

  14. Acquirement of True Stress-strain Curve Using True Fracture Strain Obtained by Tensile Test and FE Analysis

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Kyoung Yoon; Lee, Hyung Yil [Sogang University, Seoul (Korea, Republic of); Kim, Tae Hyung [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of)

    2009-10-15

    In this work, we predict a true fracture strain using load-displacement curves from tensile test and finite element analysis (FEA), and suggest a method for acquiring true stress-strain (SS) curves by predicted fracture strain. We first derived the true SS curve up to necking point from load-displacement curve. As the beginning, the posterior necking part of true SS curve is linearly extrapolated with the slope at necking point. The whole SS curve is then adopted for FE simulation of tensile test. The Bridgman factor or suitable plate correction factors are applied to pre and post FEA. In the load-true strain curve from FEA, the true fracture strain is determined as the matching point to test fracture load. The determined true strain is validated by comparing with test fracture strain. Finally, we complete the true SS curve by combining the prior necking part and linear part, the latter of which connects necking and predicted fracture points.

  15. THE CALCULATION OF STRESS-STRAIN STATE OF THREE-LAYER BEAM TAKING INTO ACCOUNT EDGE EFFECTS

    Directory of Open Access Journals (Sweden)

    Kh. M. Muselemov

    2015-01-01

    Full Text Available The work is dedicated to the calculation of the stress-strain state (SSS of the three-layer beam (TLB subject to boundary effects.In this paper, a system of differential equations of equilibrium of the threelayer beam. To solve these equations, it is necessary to know the 12 boundary conditions, co-which depend on support conditions and loading of sandwich beams under study. This system of equations is solved by the application package of mathematical modeling "Maple 5.4." The solution of this system we obtain expressions for determining de-formations and stress all components (bearing layers and filler, a three-layer beam anywhere under specified conditions of fastening the ends of the beam and its loading. 

  16. Investigation of s stressed-strained state and optimization of the T-15 facility electromagnetic system design

    International Nuclear Information System (INIS)

    Vaulina, I.G.; Gusev, S.V.; Monoszon, N.A.; Sivkova, G.N.; Spirchenko, Yu.V.; Chvartatskij, R.V.; Churakov, G.F.

    1982-01-01

    The results of investigation of a stressed-strained state (SSS) of superconducting coils of toroidal field (TFSC) of the T-15 facility are presented. The TFSC SSS dependence on the forces acting in the coil plane is reduced to solving the plane problem of the elasticity theory. The problem is solved by the finite element method according to a specially developed program. The TFSC SSS dependence on the action of tilting forces is studied by the structural mechanics method. A refined rod theory taking into account shear strain of the rod cross-section in the direction perpendicular to its axis is used. A comparative analysis of different versions of the TFSC design is carried out. A TFSC design optimized over the SSS is chosen. It is used in constructing the electromagnetic system of the T-15 facility

  17. High temperature viscoplastic ratchetting: Material response or modeling artifact

    International Nuclear Information System (INIS)

    Freed, A.D.

    1991-01-01

    Ratchetting, the net accumulation of strain over a loading cycle, is a deformation mechanism that leads to distortions in shape, often resulting in a loss of function that culminates in structural failure. Viscoplastic ratchetting is prevalent at high homologous temperatures where viscous characteristics are prominent in material response. This deformation mechanism is accentuated by the presence of a mean stress; a consequence of interaction between thermal gradients and structural constraints. Favorable conditions for viscoplastic ratchetting exist in the Stirling engines being developed by the National Aeronautics and Space Administration (NASA) and the Department of Energy (DOE) for space and terrestrial power applications. To assess the potential for ratchetting and its effect on durability of high temperature structures requires a viscoplastic analysis of the design. But ratchetting is a very difficult phenomenon to accurately model. One must therefore ask whether the results from such an analysis are indicative of actual material behavior, or if they are artifacts of the theory being used in the analysis. There are several subtle aspects in a viscoplastic model that must be dealt with in order to accurately model ratchetting behavior, and therefore obtain meaningful predictions from it. In this paper, some of these subtlties and the necessary ratchet experiments needed to obtain an accurate viscoplastic representation of a material are discussed

  18. Consistent stress-strain ductile fracture model as applied to two grades of beryllium

    International Nuclear Information System (INIS)

    Priddy, T.G.; Benzley, S.E.; Ford, L.M.

    1980-01-01

    Published yield and ultimate biaxial stress and strain data for two grades of beryllium are correlated with a more complete method of characterizing macroscopic strain at fracture initiation in ductile materials. Results are compared with those obtained from an exponential, mean stress dependent, model. Simple statistical methods are employed to illustrate the degree of correlation for each method with the experimental data

  19. Synthesis of Conductive Polymeric Nanocomposites for Applications in Responsive Materials

    Science.gov (United States)

    Chavez, Jessica

    The development of next generation "smart" textiles has emerged with significant interest due to the immense demand for high-performance wearable technology. The economic market for wearable technologies is predicted to increase significantly in both volume and value. In the next four years, the wearable technology market will be valued at $34 billion. This large demand has opened up a new research area involving smart wearable devices and conductive fabrics. Many research groups have taken various paths to study and ultimately fabricate wearable devices. Due to the limiting capabilities of conventional conductors, researchers have centered their research on the integration of conductive polymers into textile materials for applications involving responsive material. Conducive polymers are very unique organic molecules that have the ability to transfer electrons across their molecular structure due to the excess presence of pi-electrons. Conductive polymers are favored over conventional conductors because they can be easily manipulated and integrated into flexible material. Two very common conductive polymers are polyaniline (PANI) and polypyrrole (PPY) because of their large favorability in literature, high conductance values, and environmental stability. Common commercial fibers were coated via the chemical polymerization of PANI or PPY. A series of reactions were done to study the polymerization process of each polymer. The conductive efficiency of each conducting polymer is highly dependent on the type of reactants used, the acidic nature of the reaction, and the temperature of the reaction. The coated commercial fiber nanocomposites produced higher conductivity values when the polymerization reaction was run using ammonium peroxydisulfate (APS) as the oxidizing agent, run in an acidic environment, and run at very low temperatures. Other factors that improved the overall efficiency of the coated commercial fiber nanocomposites was the increase in polymer

  20. The Multiscale Material Point Method for Simulating Transient Responses

    Science.gov (United States)

    Chen, Zhen; Su, Yu-Chen; Zhang, Hetao; Jiang, Shan; Sewell, Thomas

    2015-06-01

    To effectively simulate multiscale transient responses such as impact and penetration without invoking master/slave treatment, the multiscale material point method (Multi-MPM) is being developed in which molecular dynamics at nanoscale and dissipative particle dynamics at mesoscale might be concurrently handled within the framework of the original MPM at microscale (continuum level). The proposed numerical scheme for concurrently linking different scales is described in this paper with simple examples for demonstration. It is shown from the preliminary study that the mapping and re-mapping procedure used in the original MPM could coarse-grain the information at fine scale and that the proposed interfacial scheme could provide a smooth link between different scales. Since the original MPM is an extension from computational fluid dynamics to solid dynamics, the proposed Multi-MPM might also become robust for dealing with multiphase interactions involving failure evolution. This work is supported in part by DTRA and NSFC.

  1. Smart responsive phosphorescent materials for data recording and security protection.

    Science.gov (United States)

    Sun, Huibin; Liu, Shujuan; Lin, Wenpeng; Zhang, Kenneth Yin; Lv, Wen; Huang, Xiao; Huo, Fengwei; Yang, Huiran; Jenkins, Gareth; Zhao, Qiang; Huang, Wei

    2014-04-07

    Smart luminescent materials that are responsive to external stimuli have received considerable interest. Here we report ionic iridium (III) complexes simultaneously exhibiting mechanochromic, vapochromic and electrochromic phosphorescence. These complexes share the same phosphorescent iridium (III) cation with a N-H moiety in the N^N ligand and contain different anions, including hexafluorophosphate, tetrafluoroborate, iodide, bromide and chloride. The anionic counterions cause a variation in the emission colours of the complexes from yellow to green by forming hydrogen bonds with the N-H proton. The electronic effect of the N-H moiety is sensitive towards mechanical grinding, solvent vapour and electric field, resulting in mechanochromic, vapochromic and electrochromic phosphorescence. On the basis of these findings, we construct a data-recording device and demonstrate data encryption and decryption via fluorescence lifetime imaging and time-gated luminescence imaging techniques. Our results suggest that rationally designed phosphorescent complexes may be promising candidates for advanced data recording and security protection.

  2. A Single-Expression Formula for Inverting Strain-Life and Stress-Strain Relationships

    Science.gov (United States)

    Manson, S. S.; Muralidharan, U.

    1981-01-01

    Starting with the basic fatigue lift formula, an inversion formula is derived. The inversion formula is valid over the entire life range of engineering interest for all materials examined. Conformity between the two equations is extremely close, suitable for all engineering problems. The approach used to invert the life relation is also suitable for the inversion of other formulas involving the sum of two power-law terms.

  3. MODEL SIMULATION OF GEOMETRY AND STRESS-STRAIN VARIATION OF BATAN FUEL PIN PROTOTYPE DURING IRRADIATION TEST IN RSG-GAS REACTOR

    Directory of Open Access Journals (Sweden)

    Suwardi Suwardi

    2015-03-01

    Full Text Available MODEL SIMULATION OF GEOMETRY AND STRESS-STRAIN VARIATION OF BATAN FUEL PIN PROTOTYPE DURING IRRADIATION TEST IN RSG-GAS REACTOR*. The first short fuel pin containing natural UO2 pellet in Zry4 cladding has been prepared at the CNFT (Center for Nuclear Fuel Technology then a ramp test will be performed. The present work is part of designing first irradiation experiments in the PRTF (Power Ramp Test Facility of RSG-GAS 30 MW reactor. The thermal mechanic of the pin during irradiation has simulated. The geometry variation of pellet and cladding is modeled by taking into account different phenomena such as thermal expansion, densification, swelling by fission product, thermal creep and radiation growth. The cladding variation is modeled by thermal expansion, thermal and irradiation creeps. The material properties are modeled by MATPRO and standard numerical parameter of TRANSURANUS code. Results of irradiation simulation with 9 kW/m LHR indicates that pellet-clad contacts onset from 0.090 mm initial gaps after 806 d, when pellet radius expansion attain 0.015 mm while inner cladding creep-down 0.075 mm. A newer computation data show that the maximum measured LHR of n-UO2 pin in the PRTF 12.4 kW/m. The next simulation will be done with a higher LHR, up to ~ 25 kW/m. MODEL SIMULASI VARIASI GEOMETRI DAN STRESS-STRAIN DARI PROTOTIP BAHAN BAKAR PIN BATAN SELAMA UJI IRADIASI DI REAKTOR RSG-GAS. Pusat Teknologi Bahan Bakar Nuklir (PTBBN telah menyiapkan tangkai (pin bahan bakar pendek perdana yang berisi pelet UO2 alam dalam kelongsong paduan zircaloy untuk dilakukan uji iradiasi daya naik. Penelitian ini merupakan bagian dari perancangan percobaan iradiasi pertama di PRTF (Power Ramp Test Fasility yang terpasang di reaktor serbaguna RSG-GAS berdaya 30 MW. Telah dilakukan pemodelan dan simulasi kinerja termal mekanikal pin selama iradiasi. Variasi geometri pelet dan kelongsong selama pengujian dimodelkan dengan memperhatikan fenomena ekspansi termal

  4. Response to a radioactive materials release having a transboundary impact

    International Nuclear Information System (INIS)

    1989-01-01

    Compared with an accidental release of radioactive material which is confined to the accident State, a transboundary release has added dimensions which were not fully anticipated in publications dealing with response to accidents at nuclear facilities. The new aspects to the problem may be summarized as follows: (1) A transboundary release of radioactive material, as distinct from a release which affects only the accident State, has international repercussions in the following ways: Potentially at least, the difficulties associated with a transboundary release may be magnified in those States that have no nuclear facilities of their own and may, therefore, have foreseen no need for resources to assess and deal with radioactive contamination of their food supplies, their water and their environment appropriately. International trade, in food commodities particularly, may be severely affected. Issues of compensation may arise for which the dispute settlement mechanisms are weak or non-existent. (2) Many Member States are in such geographic locations that they could be affected by a transboundary release occurring in any of their surrounding neighbour States. Planning for and responding to such an event is necessarily more difficult than planning for an accidental release from a single, identified nuclear facility. (3) Deposits of radioactive material from a distant source are apt to be highly unpredictable. Depending on weather conditions, they may be localized in a random fashion or widespread. Because of the international dimension of the problem and its essentially unpredictable character it is recommended here that planning for such events should be carried at the national or federal government level rather than at provincial government level. 14 refs

  5. On history dependence of stress-strain diagrams and creep curves under variable repeated loading

    International Nuclear Information System (INIS)

    Gokhfeld, D.A.; Sadakov, O.S.; Martynenko, M.E.

    1979-01-01

    The ability of structural alloys to 'keep in memory' the loading prehistory becomes of special importance when inelastic variable repeated loading is considered. There are two main approaches to the development of the mathematical description of this phenomenon: the inclusion of hidden state variables in the incremental theory constitutive equations (a) and construction of proper hereditary functionals (b). In this respect the assumption that the 'memory' regarding the previous deformation history is due to structural nonhomogeneity of actual materials proves to be fruitful. (orig.)

  6. Debonding analyses in anisotropic materials with strain- gradient effects

    DEFF Research Database (Denmark)

    Legarth, Brian Nyvang

    2012-01-01

    A unit cell approach is adopted to numerically analyze the effect of plastic anisotropy on damage evolution in a micro-reinforced composite. The matrix material exhibit size effects and a visco-plastic anisotropic strain gradient plasticity model accounting for such size effects is adopted....... A conventional cohesive law is extended such that both the average as well as the jump in plastic strain across the fiber-matrix interface are accounted for. Results are shown for both conventional isotropic and anisotropic materials as well as for higher order isotropic and anisotropic materials...... with and without debonding. Generally, the strain gradient enhanced material exhibits higher load carry capacity compared to the corresponding conventional material. A sudden stress drop occurs in the macroscopic stress-strain response curve due to fiber-matrix debonding and the results show that a change in yield...

  7. Quantification of Internal Stress-Strain Fields in Human Tendon: Unraveling the Mechanisms that Underlie Regional Tendon Adaptations and Mal-Adaptations to Mechanical Loading and the Effectiveness of Therapeutic Eccentric Exercise

    Science.gov (United States)

    Maganaris, Constantinos N.; Chatzistergos, Panagiotis; Reeves, Neil D.; Narici, Marco V.

    2017-01-01

    By virtue of their anatomical location between muscles and bones, tendons make it possible to transform contractile force to joint rotation and locomotion. However, tendons do not behave as rigid links, but exhibit viscoelastic tensile properties, thereby affecting the length and contractile force in the in-series muscle, but also storing and releasing elastic stain energy as some tendons are stretched and recoiled in a cyclic manner during locomotion. In the late 90s, advancements were made in the application of ultrasound scanning that allowed quantifying the tensile deformability and mechanical properties of human tendons in vivo. Since then, the main principles of the ultrasound-based method have been applied by numerous research groups throughout the world and showed that tendons increase their tensile stiffness in response to exercise training and chronic mechanical loading, in general, by increasing their size and improving their intrinsic material. It is often assumed that these changes occur homogenously, in the entire body of the tendon, but recent findings indicate that the adaptations may in fact take place in some but not all tendon regions. The present review focuses on these regional adaptability features and highlights two paradigms where they are particularly evident: (a) Chronic mechanical loading in healthy tendons, and (b) tendinopathy. In the former loading paradigm, local tendon adaptations indicate that certain regions may “see,” and therefore adapt to, increased levels of stress. In the latter paradigm, local pathological features indicate that certain tendon regions may be “stress-shielded” and degenerate over time. Eccentric exercise protocols have successfully been used in the management of tendinopathy, without much sound understanding of the mechanisms underpinning their effectiveness. For insertional tendinopathy, in particular, it is possible that the effectiveness of a loading/rehabilitation protocol depends on the topography

  8. THE STRESS-STRAIN STATE OF ELASTIC HALF-SPACE FROM RUNNING LINEAR LOAD ACTING ON THE LIMITED AND UNLIMITED EXTENT OVER ITS SURFACE

    Directory of Open Access Journals (Sweden)

    I. K. Badalakha

    2009-02-01

    Full Text Available The article shows the result of solving the problem of stress-strain state of an elastic half-space because of the load action that uniformly distributed over the line, with the use of untraditional linear dependence of deformations on stressed state that is different from the generalized Hooke’s law.

  9. ANALYSIS OF STRESS-STRAIN STATE OF REINFORCED CONCRETE PLATE AROUND SUPPORT ZONES

    Directory of Open Access Journals (Sweden)

    Oleg V. Kabantsev

    2017-03-01

    Full Text Available Structural analysis of the formation and evolution processes of structural microdestruction with the tran-sition to macrorestriction occurring during plastic deformation of masonry under biaxial stresses. The dependencies that determine the amount of the plastic phase of the deformation of masonry. Identified processes and their corre-sponding strength criteria, which play a key role in the implementation phase of plastic deformation. It is shown that plastic deformation of masonry under biaxial stresses occurs when the physical line operation of the basic ma-terials of masonry (brick and mortar. Found that the plastic properties of masonry under biaxial stresses are deter-mined by the processes occurring at the nodes of contact interaction of brick and mortar in horizontal and vertical joints. According to the results of numerical studies the values of the coefficients of ductility of masonry at different variants of mechanical characteristics of brick, mortar and adhesive strength of their interaction.

  10. Stresses, strains, and displacements in a poroelastic layered pavement model subject to a moving load

    International Nuclear Information System (INIS)

    Morshedi, C.

    1982-01-01

    The response of a layered poroelastic halfspace to a progressing normally distributed load applied at the surface is evaluated for the case in which the constant velocity of the moving load is less than that of the elastic waves in each layer. It is assumed that a steady state exists with respect to the coordinate axes attached to a moving load. A three-dimensional problem for Biot's consolidated equations is then solved by taking Fourier transforms in the horizontal directions to evaluate stresses and displacements at any point in the medium. The analysis is illustrated by numerical examples using an algorithm based on one previously developed to calculate the response to a static load for axisymmetric poroelastic layers. To reduce the amount of computation, attention is restricted to a two-dimensional problem in which the load extends infinitely in the transverse direction. Results are presented for two and three-layered pavement models composed of concrete and gravel over a clay subbase responding to moving traffic, but the method is applicable to any number of layers. The effect of varying the velocity of the load and layer properties is observed

  11. Stress-strain response of pre-compacted granular coal samples exposed to CO2, CH4, He and Ar

    NARCIS (Netherlands)

    Bergen, F. van; Hol, S.; Spiers, C.J.

    2011-01-01

    The interaction between supercritical carbon dioxide and coal has been the subject of many studies in recent years. This paper reports two different types of swelling experiments, one on confined and one on unconfined samples of pre-pressed, crushed bituminous coal, performed at gas or fluid

  12. Prediction of stress-strain state of municipal solid waste with application of soft soil creep model

    Directory of Open Access Journals (Sweden)

    Ofrikhter Vadim Grigor'evich

    Full Text Available The deformation of municipal solid waste is a complex process caused by the nature of MSW, the properties of which differ from the properties of common soils. The mass of municipal solid waste shows the mixed behaviour partially similar to granular soils, and partially - to cohesive. So, one of mechanical characteristics of MSW is the cohesion typical to cohesive soils, but at the same time the filtration coefficient of MSW has an order of 1 m/day that is characteristic for granular soils. It has been established that MSW massif can be simulated like the soil reinforced by randomly oriented fibers. Today a significant amount of the verified and well proved software products are available for numerical modelling of soils. The majority of them use finite element method (FEM. The soft soil creep model (SSC-model seems to be the most suitable for modelling of municipal solid waste, as it allows estimating the development of settlements in time with separation of primary and secondary consolidation. Unlike the soft soil, one of the factors of secondary consolidation of MSW is biological degradation, the influence of which is possible to consider at the definition of the modified parameters essential for soft soil model. Application of soft soil creep model allows carrying out the calculation of stress-strain state of waste from the beginning of landfill filling up to any moment of time both during the period of operation and in postclosure period. The comparative calculation presented in the paper is executed in Plaxis software using the soft-soil creep model in contrast to the calculation using the composite model of MSW. All the characteristics for SSC-model were derived from the composite model. The comparative results demonstrate the advantage of SSC-model for prediction of the development of MSW stress-strain state. As far as after the completion of the biodegradation processes MSW behaviour is similar to cohesion-like soils, the demonstrated

  13. Analytical solution for stress, strain and plastic instability of pressurized pipes with volumetric flaws

    International Nuclear Information System (INIS)

    Cunha, Sérgio B.; Netto, Theodoro A.

    2012-01-01

    The mechanical behavior of internally pressurized pipes with volumetric flaws is analyzed. The two possible modes of circumferentially straining the pipe wall are identified and associated to hypothesized geometries. The radial deformation that takes place by bending the pipe wall is studied by means of axisymmetric flaws and the membrane strain developed by unequal hoop deformation is analyzed with the help of narrow axial flaws. Linear elastic shell solutions for stress and strain are developed, the plastic behavior is studied and the maximum hoop stress at the flaw is related to the undamaged pipe hoop stress by means of stress concentration factors. The stress concentration factors are employed to obtain equations predicting the pressure at which the pipe fails by plastic instability for both types of flaw. These analytical solutions are validated by comparison with burst tests on 3″ diameter pipes and finite element simulations. Forty-one burst tests were carried out and two materials with very dissimilar plastic behavior, carbon steel and austenitic stainless steel, were used in the experiments. Both the analytical and the numerical predictions showed good correlation with the experimentally observed burst pressures. - Highlights: ► An analytical model for the burst of a pipe with a volumetric flaw is developed. ► Deformation, strain and stress are modeled in the elastic and plastic domains. ► The model is comprehensively validated by experiments and numerical simulations. ► The burst pressure model’s accuracy is equivalent to finite element simulations.

  14. Analytical solution for stress, strain and plastic instability of pressurized pipes with volumetric flaws

    Energy Technology Data Exchange (ETDEWEB)

    Cunha, Sergio B., E-mail: sbcunha@petrobras.com.br [PETROBRAS/TRANSPETRO, Av. Pres. Vargas 328 - 7th floor, Rio de Janeiro, RJ 20091-060 (Brazil); Netto, Theodoro A., E-mail: tanetto@lts.coppe.ufrj.br [COPPE, Federal University ot Rio de Janeiro, Ocean Engineering Department, PO BOX 68508, Rio de Janeiro - RJ (Brazil)

    2012-01-15

    The mechanical behavior of internally pressurized pipes with volumetric flaws is analyzed. The two possible modes of circumferentially straining the pipe wall are identified and associated to hypothesized geometries. The radial deformation that takes place by bending the pipe wall is studied by means of axisymmetric flaws and the membrane strain developed by unequal hoop deformation is analyzed with the help of narrow axial flaws. Linear elastic shell solutions for stress and strain are developed, the plastic behavior is studied and the maximum hoop stress at the flaw is related to the undamaged pipe hoop stress by means of stress concentration factors. The stress concentration factors are employed to obtain equations predicting the pressure at which the pipe fails by plastic instability for both types of flaw. These analytical solutions are validated by comparison with burst tests on 3 Double-Prime diameter pipes and finite element simulations. Forty-one burst tests were carried out and two materials with very dissimilar plastic behavior, carbon steel and austenitic stainless steel, were used in the experiments. Both the analytical and the numerical predictions showed good correlation with the experimentally observed burst pressures. - Highlights: Black-Right-Pointing-Pointer An analytical model for the burst of a pipe with a volumetric flaw is developed. Black-Right-Pointing-Pointer Deformation, strain and stress are modeled in the elastic and plastic domains. Black-Right-Pointing-Pointer The model is comprehensively validated by experiments and numerical simulations. Black-Right-Pointing-Pointer The burst pressure model's accuracy is equivalent to finite element simulations.

  15. Stress, strain, and temperature induced permeability changes in potential repository rocks

    International Nuclear Information System (INIS)

    Heard, H.C.; Duba, A.

    1977-01-01

    Work is in progress to assess the permeability characteristics of coarse-grained igneous rocks as affected by pressure, deviatoric stress, and temperature. In order to predict the long-term behavior of these rocks, both virgin and fractured, permeability and all principal strains resulting from an imposed deviatoric stress under various simulated lithostatic pressures are being measured. In addition, compressional as well as shear velocities and electrical conductivity are being evaluated along these principal directions. These simultaneous measurements are being made initially at 25 0 C on a 15 cm diameter by 30 cm long sample in a pressure apparatus controlled by a mini-computer. Correlation of these data with similar field observations should then allow simplified exploration for a suitable repository site as well as the prediction of the response of a mined cavity with both distance and time at this site. After emplacement of the waste canisters, the mechanical stability and hydrologic integrity of this mined repository will be directly influenced by the fracturing of the surrounding rock which results from local temperature differences and the thermal expansion of that rock. Temperatures (and, hence, these differences) in the vicinity of the repository are expected to be affected by the presence of pore fluids (single- or two-phase) in the rock, the heat capacity and the thermal conductivity of this system. In turn, these are all dependent upon lithostatic pressure, pore pressure, and stress. Thermal expansion (and fracturing) will also be affected by the lithostatic (and effective) pressure, the deviatoric stress field, and the initial anisotropy of the rock

  16. The study on stress-strain state of the spring at high temperature using ABAQUS

    Directory of Open Access Journals (Sweden)

    H Sun

    2014-01-01

    Full Text Available Cylindrical helical springs are widely used in the elements of thermal energy devices. It is necessary to guarantee the stability of the stress state of spring in high temperature. Relaxation phenomenon of stress is studied in this paper. Calculations are carried out in the environment of ABAQUS. The verification is taken out using analytical calculations.This paper describes the distribution and character of stress contour lines on the cross section of spring under the condition of instantaneous load, explicates the relaxation law with time. Research object is cylindrical helical spring, that working at high temperature. The purpose of this work is to get the stress relaxation law of spring, and to guarantee the long-term strength.This article presents the basic theory of helical spring. Establishes spring mathematical model of creep under the loads of compression and torsion. The stress formulas of each component in the cross section of spring are given. The calculation process of relaxation is analyzed in the program ABAQUS.In this paper compare the analytical formulas of spring stress with the simulation results, which are created by program ABAQUS.Finite element model for stress creep analysis in the cross section is created, material of spring – stainless steel 10X18N9T, springs are used at the temperature 650℃.At the beginning, stress-stain of spring is in the elastic state. Analyzes the change law of creep stress under the condition of constant load and a fixed compression.When analyzing under the condition of a fixed compression, the stresses are quickly decreased in most area in the cross section of spring, and the point of minimum shear stress gradually moves to the direction of outer diameter, because of this, stresses in a small area near the center increase slowly at first then decrease gradually with time. When analyzing under the condition of constant load, the stresses are quickly decreased in the around area and in creased

  17. STRESS-STRAIN STATE OF ROCKFILL DAM DOUBLE-LAYER FACE MADE OF REINFORCED CONCRETE AND SOIL-CEMENT CONCRETE

    Directory of Open Access Journals (Sweden)

    Sainov Mikhail Petrovich

    2017-05-01

    Full Text Available There was studied the stress-strain state of 215 m high rockfill dam where the seepage-control element is presented by a reinforced concrete face of soil-cement concrete placed on the under-face zone. Calculations were carried out for two possible variants of deformability of rock outline taking into account the non-linearity of its deformative properties. It was obtained that the reinforced concrete face and the soil-cement concrete under-face zone work jointly as a single construction - a double-layer face. As the face assembly resting on rock is made with a sliding joint the scheme of its static operation is similar to the that of the beam operation on the elastic foundation. At that, the upstream surface of the double-layer face is in the compressed zone and lower one is in the tensile zone. This protects the face against cracking on the upstream surface but threatens with structural failure of soil-cement concrete. In order to avoid appearance of cracks in soil-cement concrete part due to tension it is necessary to achieve proper compaction of rockfill and arrange transverse joints in the double-layer face.

  18. Algorithm for study on the stressed-strained state of thermonuclear device vacuum chambers under dynamic loads

    International Nuclear Information System (INIS)

    Zhuravleva, A.M.; Litvinov, V.B.

    1982-01-01

    The problem of dynamic analysis of stressed-strained state of vacuum chambers is vital for large thermonuclear devices during the stall of the plasma-filament apd other tpansitional operation regimes when loading for a chamber are nonstationary. To plot a mathematical model the design of the vacuum chamber is discreted on the basis of the method of final elements. To approximate vacuum shell, a plate triangular element with 3 joint points and 5 parameters in the joint is used. It is obtained due to the unity of the bemded element and the element for the flat problem. To investigate nonstationary oscillations of vacuum chambers discreted on the basis of the method of final elements, it is suggested to use the numeric conversion of the Japlace transformation. On the basis of the algorithm suggested a program of numerical function conversion is developed. Test calculations have shown a good stability of the algorithm when selecting the values of transformation parameter in the range of lower intrinsic system frequencies. The advantage of the above method is in the fact that the time-structure shift function is found instantly in the form of the series for the whole time interval and does not require temporary steps, which bring about large expenses of counting time and error accumulation

  19. Behavioural response of Phytoseiulus persimilisin inert materials for technical application.

    Science.gov (United States)

    Wendorf, Dennis; Sermann, Helga; Katz, Peter; Lerche, Sandra; Büttner, Carmen

    2009-01-01

    A large scale application of the predatory mite Phytoseiulus persimilis Athias-Henriot for use in the biological control of spider mites in the field requires testing the behaviour of Phytoseiulus persimilis in inert materials, like millet pelts and Vermiculite (1-3 mm). In laboratory studies, the distribution of the individuals in such materials, the time of remaining in the material were proved. To examine the abiotic influences on the time of remaining in the material, the dampness of the materials was varied (0%, 5% and 10%). Moreover, the influence of attitude of materials was tested. The time of emigration from the material was noted for each individual. Emigration from all dry materials was completed 15 minutes at the latest after set up of the mites. The increase of dampness had an obvious effect on the time of remaining in the material. In this respect the material millet pelts showed the most favourable effect with 10% dampness. Increasing attitude of material the mobility of predatory mites will be influenced negatively above 75 cm. Up to 50 cm, mites have not a problem to move in the material and the time of remaining can be prolonged considerably.

  20. Verification and Validation of a Three-Dimensional Generalized Composite Material Model

    Science.gov (United States)

    Hoffarth, Canio; Harrington, Joseph; Rajan, Subramaniam D.; Goldberg, Robert K.; Carney, Kelly S.; DuBois, Paul; Blankenhorn, Gunther

    2015-01-01

    A general purpose orthotropic elasto-plastic computational constitutive material model has been developed to improve predictions of the response of composites subjected to high velocity impact. The three-dimensional orthotropic elasto-plastic composite material model is being implemented initially for solid elements in LS-DYNA as MAT213. In order to accurately represent the response of a composite, experimental stress-strain curves are utilized as input, allowing for a more general material model that can be used on a variety of composite applications. The theoretical details are discussed in a companion paper. This paper documents the implementation, verification and qualitative validation of the material model using the T800-F3900 fiber/resin composite material

  1. Failure in imperfect anisotropic materials

    DEFF Research Database (Denmark)

    Legarth, Brian Nyvang

    2005-01-01

    The fundamental cause of crack growth, namely nucleation and growth of voids, is investigated numerically for a two phase imperfect anisotropic material. A unit cell approach is adopted from which the overall stress strain is evaluated. Failure is observed as a sudden stress drop and depending...

  2. Emergency response preparedness analysis for radioactive materials transportation

    International Nuclear Information System (INIS)

    Parentela, E.M.; Burli, S.S.; Sathisan, S.K.; Vodrazka, W.C.

    1994-01-01

    This paper evaluates the emergency response capabilities of first responders, specifically fire services, within the state of Nevada. It addresses issues relating to the available emergency responders such as general capabilities, jurisdictions, and response times. Graphical displays of the response units and attribute tables were created using GIS ARC/INFO. These coverages, plus the existing Census Bureau TIGER Files and highway network for the state of Nevada, were utilized to determine approximate service areas of each response unit, population density served by each response unit, population density served by each response unit and the areas that can be served by a response unit for 3, 5, 10, and 30 minutes response times. Results of the analysis enabled identification of the critical areas along the proposed highway route corridor

  3. Characterizing large strain crush response of redwood

    International Nuclear Information System (INIS)

    Cramer, S.M.; Hermanson, J.C.

    1996-12-01

    Containers for the transportation of hazardous and radioactive materials incorporate redwood in impact limiters. Redwood is an excellent energy absorber, but only the most rudimentary information exists on its crush properties. The objectives of the study were to fill the information gap by collecting triaxial load-deformation data for redwood; to use these data to characterize redwood crush, assess current wood failure theories, provide developments toward a complete stress-strain theory for redwood; and to review the literature on strain-rate effects on redwood crush performance. The load-deformation responses of redwood at temperature conditions corresponding to ambient (70 degrees F), 150 degrees F, and -20 degrees F conditions were measured in approximately 100 confined compression tests for crush levels leading to material densification. Data analysis provided a more complete description of redwood crush performance and a basis for assessing proposed general orthotropic stress-strain relationships for redwood. A review of existing literature indicated that strain-rate effects cause at most a 20 percent increase in crush stress parallel to grain

  4. Modeling the Monotonic and Cyclic Tensile Stress-Strain Behavior of 2D and 2.5D Woven C/SiC Ceramic-Matrix Composites

    Science.gov (United States)

    Li, L. B.

    2018-05-01

    The deformation of 2D and 2.5 C/SiC woven ceramic-matrix composites (CMCs) in monotonic and cyclic loadings has been investigated. Statistical matrix multicracking and fiber failure models and the fracture mechanics interface debonding approach are used to determine the spacing of matrix cracks, the debonded length of interface, and the fraction of broken fibers. The effects of fiber volume fraction and fiber Weibull modulus on the damage evolution in the composites and on their tensile stress-strain curves are analyzed. When matrix multicracking and fiber/matrix interface debonding occur, the fiber slippage relative to the matrix in the debonded interface region of the 0° warp yarns is the main reason for the emergance of stress-strain hysteresis loops for 2D and 2.5D woven CMCs. A model of these loops is developed, and histeresis loops for the composites in cyclic loadings/unloadings are predicted.

  5. Effect of Temperature Reversion on Hot Ductility and Flow Stress-Strain Curves of C-Mn Continuously Cast Steels

    Science.gov (United States)

    Dong, Zhihua; Li, Wei; Long, Mujun; Gui, Lintao; Chen, Dengfu; Huang, Yunwei; Vitos, Levente

    2015-08-01

    The influence of temperature reversion in secondary cooling and its reversion rate on hot ductility and flow stress-strain curve of C-Mn steel has been investigated. Tensile specimens were cooled at various regimes. One cooling regime involved cooling at a constant rate of 100 °C min-1 to the test temperature, while the others involved temperature reversion processes at three different reversion rates before deformation. After hot tensile test, the evolution of mechanical properties of steel was analyzed at various scales by means of microstructure observation, ab initio prediction, and thermodynamic calculation. Results indicated that the temperature reversion in secondary cooling led to hot ductility trough occurring at higher temperature with greater depth. With increasing temperature reversion rate, the low temperature end of ductility trough extended toward lower temperature, leading to wider hot ductility trough with slightly reducing depth. Microstructure examinations indicated that the intergranular fracture related to the thin film-like ferrite and (Fe,Mn)S particles did not changed with varying cooling regimes; however, the Widmanstatten ferrite surrounding austenite grains resulted from the temperature reversion process seriously deteriorated the ductility. In addition, after the temperature reversion in secondary cooling, the peak stress on the flow curve slightly declined and the peak of strain to peak stress occurred at higher temperature. With increasing temperature reversion rate, the strain to peak stress slightly increased, while the peak stress showed little variation. The evolution of plastic modulus and strain to peak stress of austenite with varying temperature was in line with the theoretical prediction on Fe.

  6. APPLICATION OF COMPUTER SIMULATION IN THE EVALUATION OF THE STRESS-STRAIN STATE OF LOAD-BEARING STRUCTURES OF BUILDINGS MASONRY

    Directory of Open Access Journals (Sweden)

    Anatoliy I. Bedov

    2017-03-01

    Full Text Available The results of studies on the analysis of the stress-strain state of the structures of bearing walls of high-hollow pottery. The way of modeling masonry finite element method. The experimental study of masonry structures produced in the Republic of Bashkortostan high-hollow pottery, set the nature of their work load, the mechanism of destruction. The results of the comparative evaluation of the calculations in the software package and the traditional “manual” calculation.

  7. Analysis of stress- strain distribution of dowel and glue line in L-type furniture joint by means of finite element method

    Directory of Open Access Journals (Sweden)

    mossayeb dalvand

    2017-08-01

    Full Text Available In this study 3D stress-strain distribution of dowel and glue line on L-type joints made of plywood doweled was investigated. Members of joints made of 11-ply hardwood plywood (Hornbeam, Beech and Alder that were 19 mm in thickness. In this study effect of beech dowels in three levels diameters (6, 8 and 10 mm and penetration of depth (9, 13 and 17 mm on bending moment capacity of L-type joints under compression loading was investigated as experimental test, then stress-strain distribution of wood dowel and glue line in specimens were simulated by means of ANSYS 15 software with finite element method (FEM.Results have shown that bending moment resistance increased with increasing dowel diameter from 6 to 8 mm, but downward trend was observed with increasing 8 to 10 mm in dowel diameter. Bending moment resistance increased with increasing penetration depth. Also, result obtained of simulation by means of ANSYS software have shown that stress-strain in dowel and glue line increased with increasing diameter of dowel and Increasing stress in joints made of diameter dowel 10 mm due to fracture in joints and decrease in resistance once. According to results obtained of model analysis, the ultimate stress of dowel and glue line occurred in the area that joints were contacted.

  8. Constitutive model for porous materials

    International Nuclear Information System (INIS)

    Weston, A.M.; Lee, E.L.

    1982-01-01

    A simple pressure versus porosity compaction model is developed to calculate the response of granular porous bed materials to shock impact. The model provides a scheme for calculating compaction behavior when relatively limited material data are available. While the model was developed to study porous explosives and propellants, it has been applied to a much wider range of materials. The early development of porous material models, such as that of Hermann, required empirical dynamic compaction data. Erkman and Edwards successfully applied the early theory to unreacted porous high explosives using a Gruneisen equation of state without yield behavior and without trapped gas in the pores. Butcher included viscoelastic rate dependance in pore collapse. The theoretical treatment of Carroll and Holt is centered on the collapse of a circular pore and includes radial inertia terms and a complex set of stress, strain and strain rate constitutive parameters. Unfortunately data required for these parameters are generally not available. The model described here is also centered on the collapse of a circular pore, but utilizes a simpler elastic-plastic static equilibrium pore collapse mechanism without strain rate dependence, or radial inertia terms. It does include trapped gas inside the pore, a solid material flow stress that creates both a yield point and a variation in solid material pressure with radius. The solid is described by a Mie-Gruneisen type EOS. Comparisons show that this model will accurately estimate major mechanical features which have been observed in compaction experiments

  9. Development and mechanical properties of construction materials from lunar simulants

    Science.gov (United States)

    Desai, Chandra S.

    1990-01-01

    The development of construction materials such as concrete from lunar soils without the use of water requires a different methodology than that used for conventional terrestrial concrete. Currently, this research involves two aspects: (1) liquefaction of lunar simulants with various additives in a furnace so as to produce a construction material like an intermediate ceramic; and (2) cyclic loading of simulant with different initial vacuums and densities with respect to the theoretical maximum densities (TMD). In both cases, bending, triaxial compression, extension, and hydrostatic tests will be performed to define the stress-strain strength response of the resulting materials. In the case of the intermediate ceramic, bending and available multiaxial test devices will be used, while for the compacted case, tests will be performed directly in the new device. The tests will be performed by simulating in situ confining conditions. A preliminary review of high-purity metal is also conducted.

  10. Planning and Preparing for Emergency Response to Transport Accidents Involving Radioactive Material. Safety Guide

    International Nuclear Information System (INIS)

    2009-01-01

    This Safety Guide provides guidance on various aspects of emergency planning and preparedness for dealing effectively and safely with transport accidents involving radioactive material, including the assignment of responsibilities. It reflects the requirements specified in Safety Standards Series No. TS-R-1, Regulations for the Safe Transport of Radioactive Material, and those of Safety Series No. 115, International Basic Safety Standards for Protection against Ionizing Radiation and for the Safety of Radiation Sources. Contents: 1. Introduction; 2. Framework for planning and preparing for response to accidents in the transport of radioactive material; 3. Responsibilities for planning and preparing for response to accidents in the transport of radioactive material; 4. Planning for response to accidents in the transport of radioactive material; 5. Preparing for response to accidents in the transport of radioactive material; Appendix I: Features of the transport regulations influencing emergency response to transport accidents; Appendix II: Preliminary emergency response reference matrix; Appendix III: Guide to suitable instrumentation; Appendix IV: Overview of emergency management for a transport accident involving radioactive material; Appendix V: Examples of response to transport accidents; Appendix VI: Example equipment kit for a radiation protection team; Annex I: Example of guidance on emergency response to carriers; Annex II: Emergency response guide.

  11. REVIEW KONSEP RESPONSIVE DESIGN DENGAN FRAMEWORK MATERIALIZE PADA WEBSITE

    Directory of Open Access Journals (Sweden)

    Cindy Novianty

    2017-09-01

    Full Text Available Responsive web design merupakan sebuah desain website yang dapat menyesuaikan tiap ukuran pada tiap device. Berdasarkan hasil dari beberapa responden menyatakan 62% responden setuju jika beberapa website yang belum mampu menyesuaikan ukuran tampilan web, 54% responden setuju bahwa desain yang responsive mempengaruhi faktor kenyamanan responden, 60% responden setuju bahwa konten utama dan fungsionalitas dari website yang sulit diakses melalui perangkat mobile, 56% responden setuju bahwa tampilan website yang kurang responsive berpengaruh buruk terhadap faktor kenyamanan responden, 52% responden setuju bahwa website yang belum mampu menyesuaikan ukuran pada tiap perangkat mobile. Dari hasil review tersebut dapat disimpulkan bahwa website yang tidak responsive mempengaruhi ketidak nyamanan para pengguna untuk mengakses informasi melalui website online.

  12. Solvent Resistant Elastomers and High TG Materials from the Same Carbosilane Backbone: Broadening the Materials Response

    National Research Council Canada - National Science Library

    Wagener, K

    2003-01-01

    .... We have directed our efforts towards solvent resistant materials that improve upon butyl rubber. Polycarobcsilanes combine the behavioral characteristics of hydrocarbon polymers and siloxane elastomers...

  13. REVIEW KONSEP RESPONSIVE DESIGN DENGAN FRAMEWORK MATERIALIZE PADA WEBSITE

    OpenAIRE

    Cindy Novianty

    2017-01-01

    Responsive web design merupakan sebuah desain website yang dapat menyesuaikan tiap ukuran pada tiap device. Berdasarkan hasil dari beberapa responden menyatakan 62% responden setuju jika beberapa website yang belum mampu menyesuaikan ukuran tampilan web, 54% responden setuju bahwa desain yang responsive mempengaruhi faktor kenyamanan responden, 60% responden setuju bahwa konten utama dan fungsionalitas dari website yang sulit diakses melalui perangkat mobile, 56% responden setuju bahwa tampil...

  14. Dynamic compressive mechanical response of a soft polymer material

    NARCIS (Netherlands)

    Fan, J.T.; Weerheijm, J.; Sluys, L.J.

    2015-01-01

    The dynamic mechanical behaviour of a soft polymer material (Clear Flex 75) was studied using a split Hopkinson pressure bar (SHPB) apparatus. Mechanical properties have been determined at moderate to high strain rates. Real time deformation and fracture were recorded using a high-speed camera.

  15. Microwave assisted synthesis of Magnetically responsive composite materials

    Czech Academy of Sciences Publication Activity Database

    Šafařík, Ivo; Horská, Kateřina; Pospíšková, K.; Maděrová, Zdeňka; Šafaříková, Miroslava

    2013-01-01

    Roč. 49, č. 1 (2013), s. 213-218 ISSN 0018-9464 R&D Projects: GA ČR(CZ) GAP503/11/2263; GA MŠk LH12190 Institutional support: RVO:67179843 Keywords : magnetic materials * magnetic modification * magnetic separation * microwaves Subject RIV: EH - Ecology, Behaviour Impact factor: 1.213, year: 2013

  16. Response of inherently brittle materials on higher loading rates

    Czech Academy of Sciences Publication Activity Database

    Chlup, Zdeněk; Flašar, Petr; Dlouhý, Ivo

    2010-01-01

    Roč. 77, č. 2 (2010), s. 359-366 ISSN 0013-7944 R&D Projects: GA ČR GA101/09/1821; GA AV ČR IAA200410502 Institutional research plan: CEZ:AV0Z20410507 Keywords : Dynamic fracture toughness * Stress intensity factor * Ceramics Subject RIV: JL - Materials Fatigue, Friction Mechanics Impact factor: 1.571, year: 2010

  17. Design of responsive materials using topologically interlocked elements

    International Nuclear Information System (INIS)

    Molotnikov, A; Gerbrand, R; Qi, Y; Simon, G P; Estrin, Y

    2015-01-01

    In this work we present a novel approach to designing responsive structures by segmentation of monolithic plates into an assembly of topologically interlocked building blocks. The particular example considered is an assembly of interlocking osteomorphic blocks. The results of this study demonstrate that the constraining force, which is required to hold the blocks together, can be viewed as a design parameter that governs the bending stiffness and the load bearing capacity of the segmented structure. In the case where the constraining forces are provided laterally using an external frame, the maximum load the assembly can sustain and its stiffness increase linearly with the magnitude of the lateral load applied. Furthermore, we show that the segmented plate with integrated shape memory wires employed as tensioning cables can act as a smart structure that changes its flexural stiffness and load bearing capacity in response to external stimuli, such as heat generated by the switching on and off an electric current. (paper)

  18. Materializing a responsive interior: designing minimum energy structures

    DEFF Research Database (Denmark)

    Mossé, Aurélie; Kofod, Guggi; Ramsgaard Thomsen, Mette

    2011-01-01

    This paper discusses a series of design-led experiments investigating future possibilities for architectural materialization relying on minimum energy structures as an example of adaptive structure. The structures have been made as laminates of elastic membrane under high tension with flexible...... (Lendlein, Kelch 2002) or light (van Oosten, Bastiaansen et al. 2009). All in all, this approach could form a whole new design paradigm, in which efficient 2D-manufacturing can lead to highly flexible, low weight and adaptable 3D-structures. This is illustrated by the design and manufacture of electro...

  19. Mechanical Behaviour of Conventional Materials at Experimental Conditions of Deep Drawing Technological Process

    Science.gov (United States)

    Nikolov, N.; Pashkouleva, D.; Kavardzhikov, V.

    2012-09-01

    The paper deals with experimental investigations on the mechanical behaviour of body-centred-cubic (BCC) and face-centred-cubic (FCC)-conventionally structured sheet metalic-metalic materials under stress-strain conditions of a deep drawing process determined by a coefficient close to the limiting one for Steel 08 and punch diameter of 50 mm. The mechanical characteristics of the investigated materials are identified by one-dimensional tension tests. The materials' responses, as results of identical loading conditions, are described by the change of blank sizes and characteristics of the forming processes. The chosen deformation path ensures obtaining a qualitative steel piece and leads to failures of aluminium and brass blanks. The reported results could be useful for investigations and predictions of the mechanical responses of such type metallic structures applying microscopic instrumented observations and numerical simulations.

  20. Loading technique for dynamic response studies of geological materials

    International Nuclear Information System (INIS)

    Butler, R.I.; Forrestal, M.J.

    1979-04-01

    A loading technique to study the dynamic response of tuff was explored. Loading is provided by electrically exploding etched copper mesh patterns with current from a capacitor discharge. Pressure pulses with peak pressures up to 1.25 kbar and 0.10 to 0.20 ms durations were measured with a pressure bar. The upper value of peak pressure was limited by the strength of the experimental apparatus, and higher pressure generation is possible with a redesign of test hardware. 6 figures, 2 tables

  1. Response of plant species to coal-mine soil materials

    Energy Technology Data Exchange (ETDEWEB)

    Day, A.D.; Tucker, T.C.; Thames, J.L.

    1983-03-01

    The two-year Black Mesa Coal Mine Research Study on the area near Kayenta, Arizona investigating the growth and establishment of seven plant species in unmined soil and coal-mined soils found that plant species grew better in unmined soil and that irrigation is essential during seedling establishment for the effective stabilization of coal-mined soils in a semi-arid environment. Differences among the species included variations in germination, response to irrigation, seedling establishment, and stem growth. 12 references, 2 figures, 2 tables.

  2. Simulation of the dynamic response of radioactive material shipping package - railcar systems during coupling operations

    International Nuclear Information System (INIS)

    Fields, S.R.

    1981-12-01

    The basic equations of the computer model CARDS (Cask-Railcar Dynamic Simulator), developed for the U.S. Nuclear Regulatory Commission to simulate the dynamic behavior of radioactive material shipping package - railcar systems, are presented. A companion model, CARRS (Casks Railcar Response Spectrum Generator), that generates system response as frequency response spectra is also presented in terms of its basic equations

  3. Simulation of the dynamic response of radioactive material shipping package-railcar systems during coupling operations

    International Nuclear Information System (INIS)

    Fields, S.R.

    1983-10-01

    The basic equations of the computer model CARDS (Cask-Railcar Dynamic Simulator), developed for the US Nuclear Regulatory Commission to simulate the dynamic behavior of radioactive material shipping package - railcar systems, are presented. A companion model, CARRS (Cask Railcar Response Spectrum Generator), that generates system response as frequency response spectra is also presented in terms of its basic equations. 1 reference, 18 figures

  4. Axial and transverse stress-strain characterization of the EU dipole high current density Nb{sub 3}Sn strand

    Energy Technology Data Exchange (ETDEWEB)

    Nijhuis, A; Ilyin, Y; Abbas, W [Faculty of Science and Technology, Low Temperature Division, University of Twente, PO Box 217, 7500 AE Enschede (Netherlands)], E-mail: a.nijhuis@tnw.utwente.nl

    2008-06-15

    We have measured the critical current (I{sub c}) of a high current density Nb{sub 3}Sn strand subjected to spatial periodic bending, periodic contact stress and uniaxial strain. The strand is destined for the cable-in-conduit conductors (CICC) of the European dipole (EDIPO) 12.5 T superconducting magnet test facility. The spatial periodic bending was applied on the strand, using the bending wavelengths from 5 to 10 mm with a peak bending strain of 1.5%, a periodic contact stress with a periodicity of 4.7 mm and a stress level exceeding 250 MPa. For the uniaxial strain characterization, the voltage-current characteristics were measured with an applied axial strain from -0.9% to +0.3%, with a magnetic field from 6 to 14 T, temperature from 4.2 to 10 K and currents up to almost 900 A. In addition the axial stiffness was determined by a tensile axial stress-strain test. The characterization of the strand is essential for understanding the behaviour of the strand under mainly axial thermal stress variation during cool down and transverse electromagnetic forces during charging, which is essential for the design of the CICC for the dipole magnet. The strand appears to be fully reversible in the compressive regime during the axial strain testing, while in the tensile regime, the behaviour is already irreversibly degraded when reaching the maximum in the critical current versus strain characteristic. The degradation is accentuated by an immediate decrease of the n value by a factor of 2. The parameters for the improved deviatoric strain description are derived from the I{sub c} data, giving the accuracy of the scaling with a standard deviation of 4 A, which is by far within the expected deviation for the large scale strand production of such a high J{sub c} strand. The I{sub c} versus the applied bending strain follows the low resistivity limit, indicative of full interfilament current transfer, while a strong decrease is observed at a peak bending strain of {approx}0

  5. Dynamic Response of Coarse Granular Material to Wave Load

    DEFF Research Database (Denmark)

    Ibsen, Lars Bo

    1998-01-01

    The soil beneath vertical breakwaters is subjected to a combination of forces induced by the waves. The forces acting on the soil can be characterized as 1) static load due to submerged weight of the structure, 2) quasi-static forces induced by cyclic wave loading, and 3) wave impact from breaking...... waves. The stress conditions in the soil below a foundation exposed to these types of loading are very complex. The key to explain and quantify the soil response beneath a vertical breakwater is to understand the role of the volume changes and to be able to model these correctly. It is shown...... that the volume changes in soil subjected to static and dynamic loading are controlled by the characteristic line. Experiments have been performed to study the factors that influence the location of the characteristic line in drained and undrained tests for various types of sand and various types of loading...

  6. Ultrasound elastography of the lower uterine segment in women with a previous cesarean section: Comparison of in-/ex-vivo elastography versus tensile-stress-strain-rupture analysis.

    Science.gov (United States)

    Seliger, Gregor; Chaoui, Katharina; Lautenschläger, Christine; Jenderka, Klaus-Vitold; Kunze, Christian; Hiller, Grit Gesine Ruth; Tchirikov, Michael

    2018-06-01

    The purpose of this study was to assess, if the biomechanical properties of the lower uterine segment (LUS) in women with a previous cesarean section (CS) can be determined by ultrasound (US) elastography. The first aim was to establish an ex-vivo LUS tensile-stress-strain-rupture(break point) analysis with the possibility of simultaneously using US elastography. The second aim was to investigate the relationship between measurement results of LUS stiffness using US elastography in-/ex-vivo with results of tensile-stress-strain-rupture analysis, and to compare different US elastography LUS-stiffness-measurement methods ex-vivo. An explorative experimental, in-/ex-vivo US study of women with previous CS was conducted. LUS elasticity was measured by point Shear Wave Elastography (pSWE) and bidimensional Shear-Wave-Elastography (2D-SWE) first in-vivo during preoperative examination within 24 h before repeat CS (including resection of the thinnest part of the LUS = uterine scar area during CS), second within 1 h after operation during the ex-vivo experiment, followed by tensile-stress-strain-rupture analysis. Pearson's correlation coefficient and scatter plots, Bland-Altman plots and paired T-tests, were used. Thirty three women were included in the study; elastography measurements n = 1412. The feasibility of ex-vivo assessment of LUS by quantitative US elastography using pSWE and 2D-SWE to detect stiffness of LUS was demonstrated. The strongest correlation with tensile-stress-strain analysis was found in the US elastography examination carried out with 2D-SWE (0.78, p break point - as a surrogate marker for the risk of rupture of the LUS after CS - is linearly dependent on the thickness of the LUS in the scar area (Coefficient of correlation: 0.79, p even at less stroke/strain than would be expected by their thickness. This study confirms that US elastography can help in determining viscoelastic properties of the LUS in women with a previous CS. The

  7. Mathematical Model of Stress-Strain State of Curved Tube of Non-Circular Cross-Section with Account of Technological Wall Thickness Variation

    Science.gov (United States)

    Pirogov, S. P.; Ustinov, N. N.; Smolin, N. I.

    2018-05-01

    A mathematical model of the stress-strain state of a curved tube of a non-circular cross-section is presented, taking into account the technological wall thickness variation. On the basis of the semi-membrane shell theory, a system of linear differential equations describing the deformation of a tube under the effect of pressure is obtained. To solve the boundary value problem, the method of shooting is applied. The adequacy of the proposed mathematical model is verified by comparison with the experimental data and the results of the calculation of tubes by the energy method.

  8. Investigation research on autonomous responsive materials; Jiritsu oto zairyo ni kansuru chosa kenkyu

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1996-03-01

    A survey was made on autonomous responsive materials as a new material which reversibly change molecular structures and the aggregation state according to external stimuli. Autonomous responsive materials imitate environmental responsibility in the living organism system and have sensing, control and active functions for external stimuli. The materials are highly efficient and environmentally friendly. In biomimetic materials for soft actuators, drastic changes by temperature of elastic modulus of water-swollen hydrogel are used to the motion. In order to molecularly design stimulus-responsible polymer gel, studied are the relation between the micro structure and stimulus responsibility, dynamic correlation between the micro structure and the macro structure, etc. In the biomedical field, new cure and diagnosis using innovative materials are expected, and the application of autonomous responsive materials to the field is studied. For example, using hydrogel responding the temperature and the surface and controlling by temperature the interaction with components of the organism such as protein and cells, drug delivery in the organism is optimized. Also studied is the application of hydrophilic/hydrophobic changes by temperature to the chromatography. 215 refs., 47 figs., 11 tabs.

  9. Emergency response planning and preparedness for transport accidents involving radioactive material

    International Nuclear Information System (INIS)

    1988-01-01

    The purpose of this Guide is to provide assistance to public authorities and others (including consignors and carriers of radioactive materials) who are responsible for ensuring safety in establishing and developing emergency response arrangements for responding effectively to transport accidents involving radioactive materials. This Guide is concerned mainly with the preparation of emergency response plans. It provides information which will assist those countries whose involvement with radioactive materials is just beginning and those which have already developed their industries involving radioactive materials and attendant emergency plans, but may need to review and improve these plans. The need for emergency response plans and the ways in which they are implemented vary from country to country. In each country, the responsible authorities must decide how best to apply this Guide, taking into account the actual shipments and associated hazards. In this Guide the emergency response planning and response philosophy are outlined, including identification of emergency response organizations and emergency services that would be required during a transport accident. General consequences which could prevail during an accident are described taking into account the IAEA Regulations for the Safe Transport of Radioactive Material. 43 refs, figs and tabs

  10. Novel High-Activity Organic Piezoelectric Materials - From Single-Molecule Response to Energy Harvesting Films

    Science.gov (United States)

    2015-08-24

    for micro- and nano-electronic energy generation and conversion for self-powered sensors , haptic displays, and responsive shape-changing materials...conversion for self-powered sensors , haptic displays, and responsive shape-changing materials. With this project, we have established that dramatic...flexible devices and applications from touch sensors to medical implants have not been matched with solutions for energy storage, conversion and generation

  11. DEM Simulation of Biaxial Compression Experiments of Inherently Anisotropic Granular Materials and the Boundary Effects

    Directory of Open Access Journals (Sweden)

    Zhao-Xia Tong

    2013-01-01

    Full Text Available The reliability of discrete element method (DEM numerical simulations is significantly dependent on the particle-scale parameters and boundary conditions. To verify the DEM models, two series of biaxial compression tests on ellipse-shaped steel rods are used. The comparisons on the stress-strain relationship, strength, and deformation pattern of experiments and simulations indicate that the DEM models are able to capture the key macro- and micromechanical behavior of inherently anisotropic granular materials with high fidelity. By using the validated DEM models, the boundary effects on the macrodeformation, strain localization, and nonuniformity of stress distribution inside the specimens are investigated using two rigid boundaries and one flexible boundary. The results demonstrate that the boundary condition plays a significant role on the stress-strain relationship and strength of granular materials with inherent fabric anisotropy if the stresses are calculated by the force applied on the wall. However, the responses of the particle assembly measured inside the specimens are almost the same with little influence from the boundary conditions. The peak friction angle obtained from the compression tests with flexible boundary represents the real friction angle of particle assembly. Due to the weak lateral constraints, the degree of stress nonuniformity under flexible boundary is higher than that under rigid boundary.

  12. Magnetically responsive (nano) composites as perspective materials for environmental technology applications

    Czech Academy of Sciences Publication Activity Database

    Šafařík, Ivo; Šafaříková, Miroslava

    -, č. 0 (2010), s. 85-90 R&D Projects: GA MPO(CZ) 2A-1TP1/094; GA MŠk OC09052 Institutional research plan: CEZ:AV0Z60870520 Keywords : magnetically responsive materials * ( nano )biocomposites * environmental technology Subject RIV: JI - Composite Materials

  13. Temperature response of biological materials to pulsed non-ablative CO2 laser irradiation

    NARCIS (Netherlands)

    Brugmans, M. J.; Kemper, J.; Gijsbers, G. H.; van der Meulen, F. W.; van Gemert, M. J.

    1991-01-01

    This paper presents surface temperature responses of various tissue phantoms and in vitro and in vivo biological materials in air to non-ablative pulsed CO2 laser irradiation, measured with a thermocamera. We studied cooling off behavior of the materials after a laser pulse, to come to an

  14. Study of improving the thermal response of a construction material containing a phase change material

    Science.gov (United States)

    Laaouatni, A.; Martaj, N.; Bennacer, R.; Elomari, M.; El Ganaoui, M.

    2016-09-01

    The use of phase change materials (PCMs) for improving the thermal comfort in buildings has become an attractive application. This solution contributes to increasing the thermal inertia of the building envelope and reducing power consumption. A building element filled with a PCM and equipped with ventilation tubes is proposed, both for increasing inertia and contributing to refreshing building envelope. A numerical simulation is conducted by the finite element method in COMSOL Multiphysics, which aims to test the thermal behaviour of the developed solution. An experimental study is carried out on a concrete block containing a PCM with ventilation tubes. The objective is to see the effect of PCM coupled with ventilation on increasing the inertia of the block. The results show the ability of this new solution to ensure an important thermal inertia of a building.

  15. Analysis of the material configurations and influence on the dynamic response

    Directory of Open Access Journals (Sweden)

    Murčinková Zuzana

    2018-01-01

    Full Text Available The paper presents the analysis of the material configuration of composites based on the measurement of their dynamic response. The article presents the measurement scheme, the design of the measuring stand together with the analysis of the results. Moreover, it analyses the FFT spectrums of layered long fibre composite, short fibre composites of different fibres materials and homogeneous materials as steel and aluminium alloy.

  16. Planning and preparing for emergency response to transport accidents involving radioactive material. Safety guide

    International Nuclear Information System (INIS)

    2005-01-01

    The objective of this Safety Guide is to provide guidance to the public authorities and others (including consignors, carriers and emergency response authorities) who are responsible for developing and establishing emergency arrangements for dealing effectively and safely with transport accidents involving radioactive material. It may assist those concerned with establishing the capability to respond to such transport emergencies. It provides guidance for those Member States whose involvement with radioactive material is just beginning. It also provides guidance for those Member States that have already developed their radioactive material industries and the attendant emergency plans but that may need to review and improve these plans

  17. The development and characterization of stimuli-responsive systems for performance materials

    Science.gov (United States)

    Gordon, Melissa B.

    In nature, living organisms adjust to their surroundings by responding to environmental cues, such as light, temperature or force. Stimuli-triggered processes, such as the contraction of eyes in response to bright light or wound healing in skin after a cut, motivate the design of "smart" materials which are designed to respond to environmental stimuli. Responsive materials are used as self-healing materials, shape memory polymers and responsive coatings; moreover, responsive materials may also be employed as model systems, which enhance understanding of complex behavior. The overall goal of this work is to design a material that offers self-healing functionality, which will allow for self-repair following material fatigue or failure, and increased strength in response to ballistic or puncture threats through the incorporation of colloidal particles. The target application for this material is as a protective barrier in extreme environments, such as outer space. Towards this end, the dissertation is focused on the development and characterization of each component of the protective material by (1) designing and testing novel light- and force-sensitive polymers for self-healing applications and (2) examining and characterizing long-time behavior (i.e., aging) in model thermoreversible colloidal gels and glasses. Towards the development of novel stimuli-responsive materials, a photo-responsive polymer network is developed in which a dynamic bond is incorporated into the network architecture to enable a light-triggered, secondary polymerization, which increases the modulus by two orders of magnitude while strengthening the network by over 100%. Unlike traditional two-stage polymerization systems, in which the secondary polymerization is triggered by a leachable photoinitiator, the dynamic nature is imparted by the material itself via the dissociation of its own crosslinks to become stronger in response to light. Several attributes of the photo-responsive network are

  18. The effect of priming materialism on women's responses to thin-ideal media.

    Science.gov (United States)

    Ashikali, Eleni-Marina; Dittmar, Helga

    2012-12-01

    Consumer culture is characterized by two prominent ideals: the 'body perfect' and the material 'good life'. Although the impact of these ideals has been investigated in separate research literatures, no previous research has examined whether materialism is linked to women's responses to thin-ideal media. Data from several studies confirm that the internalization of materialistic and body-ideal values is positively linked in women. After developing a prime for materialism (N = 50), we present an experimental examination (N = 155) of the effects of priming materialism on women's responses to thin-ideal media, using multiple outcome measures of state body dissatisfaction. Priming materialism affects women's body dissatisfaction after exposure to thin media models, but differently depending on the dimension of body image measured. The two main novel findings are that (1) priming materialism heightens the centrality of appearance to women's self-concept and (2) priming materialism influences the activation of body-related self-discrepancies (BRSDs), particularly for highly materialistic women. Exposure to materialistic media has a clear influence on women's body image, with trait materialism a further vulnerability factor for negative exposure effects in response to idealized, thin media models. ©2011 The British Psychological Society.

  19. IAEA consultants' meeting on thermal response of plasma facing materials and components

    International Nuclear Information System (INIS)

    Janev, R.K.

    1990-07-01

    The present Summary Report contains brief proceedings and the main conclusions and recommendations of the IAEA Consultants' Meeting on ''Thermal Response of Plasma Facing Materials and Components'', which was organized by the IAEA Atomic and Molecular Data Unit and held on June 11-13, 1990, in Vienna, Austria. The Report also includes a categorization and assessment of currently studied plasma facing materials, a classification scheme of material properties data, required in fusion reactor design, and a survey of the urgently needed material properties data. (author)

  20. Mathematical modeling of stress-strain state of the system HPP building - soil base with account for the phased construction of the building

    Directory of Open Access Journals (Sweden)

    Orekhov Vyacheslav Valentinovich

    Full Text Available The interaction process of a power plant building with the soil base is studied basing on mathematical modeling of the construction process of Kambarata-2 HPP, taking into account the excavation of foundation pit, the concreting schedule of the building construction, the HPP units putting into operation and territory planning. Mathematical modeling of stress-strain state of the system “power plant - soil base” in the process of construction was performed by using the computer program “Zemlya” (the Earth, which implements the method of finite elements. Such a behavior of soil was described using elastoplastic soil model, the parameters of which were determined from the results of the triaxial tests. As shown by the results of the research, the continuous change of settlement, slope, deflection and torsion of the bottom plate and accordingly change of stressed-strained state of power plant are noted during the construction process. The installed HPP construction schedule, starting from the construction of the first block and the adjacent mounting platform, is leading to the formation of initial roll of bottom plate to the path of the mounting pad. In the process of further construction of powerhouse, up to the 29th phase of construction (out of 40, a steady increase in its subsidence (maximum values of about 4.5 cm is noted. Filling of foundation pit hollows and territorial planning of the construction area lead to drastic situation. In this case, as a territory planning points exceeded the relief, the plastic deformation in the soil evolves, resulting in significant subsidence of the bottom plate under the first block (up to 7.4 cm. As a result, the additional subsidence of the soil of bottom plate edges lead to the large vertical movement in relation to its central part and it is bent around the X axis, resulting in a large horizontal tensile stress values of Sz (up to 2.17 MPa in the constructive elements of the upper part of the

  1. Conceptual design report, Hazardous Materials Management and Emergency Response (HAMMER) Training Center

    Energy Technology Data Exchange (ETDEWEB)

    Kelly, K.E. [Westinghouse Hanford Co., Richland, WA (United States)

    1994-11-09

    For the next 30 years, the main activities at the US Department of Energy (DOE) Hanford Site will involve the management, handling, and cleanup of toxic substances. If the DOE is to meet its high standards of safety, the thousands of workers involved in these activities will need systematic training appropriate to their tasks and the risks associated with these tasks. Furthermore, emergency response for DOE shipments is the primary responsibility of state, tribal, and local governments. A collaborative training initiative with the DOE will strengthen emergency response at the Hanford Site and within the regional communities. Local and international labor has joined the Hazardous Materials Management and Emergency Response (HAMMER) partnership, and will share in the HAMMER Training Center core programs and facilities using their own specialized trainers and training programs. The HAMMER Training Center will provide a centralized regional site dedicated to the training of hazardous material, emergency response, and fire fighting personnel.

  2. Conceptual design report, Hazardous Materials Management and Emergency Response (HAMMER) Training Center

    International Nuclear Information System (INIS)

    Kelly, K.E.

    1994-01-01

    For the next 30 years, the main activities at the US Department of Energy (DOE) Hanford Site will involve the management, handling, and cleanup of toxic substances. If the DOE is to meet its high standards of safety, the thousands of workers involved in these activities will need systematic training appropriate to their tasks and the risks associated with these tasks. Furthermore, emergency response for DOE shipments is the primary responsibility of state, tribal, and local governments. A collaborative training initiative with the DOE will strengthen emergency response at the Hanford Site and within the regional communities. Local and international labor has joined the Hazardous Materials Management and Emergency Response (HAMMER) partnership, and will share in the HAMMER Training Center core programs and facilities using their own specialized trainers and training programs. The HAMMER Training Center will provide a centralized regional site dedicated to the training of hazardous material, emergency response, and fire fighting personnel

  3. Influence of material anisotropy on the hydroelastic response of composite plates in water

    Science.gov (United States)

    Akcabay, Deniz Tolga; Young, Yin Lu

    2018-03-01

    Flexible lightweight plate-like lifting surfaces in external flows have a diverse range of use from propelling and controlling marine and aerospace vehicles to converting wind and ocean energy to electrical energy. Design and analysis of such structures are complex for underwater applications where the water density is much higher than air. The hydrodynamic loads, which vary with the inflow speed, can significantly alter the dynamic response and stability. This paper focuses on the hydroelastic response of composite plates in water. The results show that the dynamics and stability of the structure can be significantly modified by taking advantage of the material anisotropic; on the contrary, careless composite material designs may lead to unwanted dynamic instability failures. The resonance frequencies, divergence speeds, and fluid loss coefficients change with material anisotropy and hydrodynamic loads. The resonance frequencies are much lower in water than in air. The critical divergence speed increases, if the principal fiber direction is oriented towards the inflow. Hydrodynamic damping is shown to be much higher than the material damping, and tend to increase with flow speed and to decrease with increasing modal frequency. The paper derives Response Amplitude Operators (RAOs) for sample composite plates in water and use them to predict the motion response when subject to stochastic flow excitations. We show how material anisotropy can be used to passively tailor the plate vibration response spectrum to limit or enhance flow-induced vibrations of the plate depending on the desired applications.

  4. Development of conventional fatigue database for structure materials of nuclear power plant

    International Nuclear Information System (INIS)

    Yang Bing

    2002-01-01

    Management system of the conventional fatigue database for structure materials of nuclear power plant (NPP) is developed. The database included the parameters of design curves, i.e., the stress-life, survival probability-stress-life, strain-life, survival probability-strain-life, stress-strain and survival probability-stress-strain curves, and corresponding information of materials and testing conditions. Two ways, by materials name or by the inter-bounds of material mechanical properties, are constructed to search the database. From the searched information it can be conveniently performed of the conventional fatigue design analysis and reliability assessment of structures

  5. Medical Preparedness and Response for a Nuclear or Radiological Emergency. Training Materials

    International Nuclear Information System (INIS)

    2014-01-01

    In almost all nuclear and radiological emergencies, local emergency services (e.g. local medical, law enforcement, and fire brigades) will have the most important role in the early response. Within hours, hospitals may also have an important role to play in the response at the local level. Since nuclear and radiological emergencies are rare, medical responders often have little or no experience in dealing with this type of emergency and inexperience may lead to an inadequate response. For this reason, training in medical preparedness and response for a nuclear or radiological emergency is an important aspect of preparedness and response activities. These materials are designed for use at a training course on medical preparedness and response for a nuclear or radiological emergency. They contain a wide range of lectures and supporting materials, which cover the basic topics and more specific areas of medical preparedness and response. Therefore, in planning their specific courses, organizers are encouraged to choose those lectures and supportive materials from the CD-ROM that best match their training priorities. Materials on the CD-ROM address the following areas: • Terrorism in Perspective; • Malicious Act Scenarios; • Providing Information to the Medical Community and the Public; • Medical Response to a Radiation Mass Casualty Event; • Handling of Contaminated Persons in Malicious Events; • Planning and Preparedness for Medical Response to Malicious Events with Radioactive Material; • Handling the Bodies of Decedents Contaminated with Radioactive Material; • Radiation Emergencies: Scope of the Problem; • Common Sources of Radiation; • Basic Concepts of Ionizing Radiation; • Basic Concepts of Radiation Protection; • Biological Effects of Ionizing Radiation – Basic Notions; • Basics of Radiopathology; • External Radioactive Contamination; • Internal Radioactive Contamination; • Acute Radiation Syndrome; • Cutaneous Radiation

  6. Applications of pulsed energy sources and hydrodynamic response to materials science

    International Nuclear Information System (INIS)

    Perry, F.; Nelson, W.

    1993-01-01

    The dynamic response of materials to pulsed, relativistic electron beams was studied for materials science applications over two decades ago. Presently, intense light ion beams are being explored for materials science applications. These include the Ion Beam Surface Treatment (IBEST) of materials for producing stronger and more corrosion-resistant materials and the evaporative deposition of polycrystalline thin films. Laser sources are also being extensively utilized as pulsed energy sources in medical science and in clinical applications. In particular, laser-tissue interactions are being investigated for laser angioplasty and surgery as well as cancer therapy. The understanding of the energy deposition and hydrodynamic response of a wide range of materials is essential to the success of these applications. In order to address these materials science applications, the authors are utilizing and developing high quality, energy deposition-hydrodynamic code techniques which can aid in the design and interpretation of experiments. Consequently, the authors strongly encourage the development of 3-dimensional, species-selective diagnostic techniques, e.g. Resonant Holographic Interferometry Spectroscopy (RHIS), to be used in analyzing the ablation plume in the thin film deposition experiments. In this presentation they show the results and discuss the limitations of calculations for these materials applications. They also discuss the status of the RHIS diagnostic

  7. 4D bioprinting: the next-generation technology for biofabrication enabled by stimuli-responsive materials.

    Science.gov (United States)

    Li, Yi-Chen; Zhang, Yu Shrike; Akpek, Ali; Shin, Su Ryon; Khademhosseini, Ali

    2016-12-02

    Four-dimensional (4D) bioprinting, encompassing a wide range of disciplines including bioengineering, materials science, chemistry, and computer sciences, is emerging as the next-generation biofabrication technology. By utilizing stimuli-responsive materials and advanced three-dimensional (3D) bioprinting strategies, 4D bioprinting aims to create dynamic 3D patterned biological structures that can transform their shapes or behavior under various stimuli. In this review, we highlight the potential use of various stimuli-responsive materials for 4D printing and their extension into biofabrication. We first discuss the state of the art and limitations associated with current 3D printing modalities and their transition into the inclusion of the additional time dimension. We then suggest the potential use of different stimuli-responsive biomaterials as the bioink that may achieve 4D bioprinting where transformation of fabricated biological constructs can be realized. We finally conclude with future perspectives.

  8. Project plan, Hazardous Materials Management and Emergency Response Training Center: Project 95L-EWT-100

    International Nuclear Information System (INIS)

    Borgeson, M.E.

    1994-01-01

    The Hazardous Materials Management and Emergency Response (HAMMER) Training Center will provide for classroom lectures and hands-on practical training in realistic situations for workers and emergency responders who are tasked with handling and cleanup of toxic substances. The primary objective of the HAMMER project is to provide hands-on training and classroom facilities for hazardous material workers and emergency responders. This project will also contribute towards complying with the planning and training provisions of recent legislation. In March 1989 Title 29 Code of Federal Regulations Occupational Safety and Health Administration 1910 Rules and National Fire Protection Association Standard 472 defined professional requirements for responders to hazardous materials incidents. Two general types of training are addressed for hazardous materials: training for hazardous waste site workers and managers, and training for emergency response organizations

  9. Embedded Fibre Bragg Grating Sensor Response Model: Crack Growing Detection in Fibre Reinforced Plastic Materials

    DEFF Research Database (Denmark)

    Pereira, Gilmar Ferreira; Mikkelsen, Lars Pilgaard; McGugan, Malcolm

    2015-01-01

    This article presents a novel method to simulate the sensor output response of a Fibre Bragg Grating (FBG) sensor when embedded in a host material (Composite material or adhesive), during a crack growing/damage event. A finite element model of the crack growth mechanisms was developed, and differ...... the applicability of this technique to more complicated structures, and to be used as a structural health monitoring design tool....

  10. Supporting system in emergency response plan for nuclear material transport accidents

    International Nuclear Information System (INIS)

    Nakagome, Y.; Aoki, S.

    1993-01-01

    As aiming to provide the detailed information concerning nuclear material transport accidents and to supply it to the concerned organizations by an online computer, the Emergency Response Supporting System has been constructed in the Nuclear Safety Technology Center, Japan. The system consists of four subsystems and four data bases. By inputting initial information such as name of package and date of accident, one can obtain the appropriate initial response procedures and related information for the accident immediately. The system must be useful for protecting the public safety from nuclear material transport accidents. But, it is not expected that the system shall be used in future. (J.P.N.)

  11. Adaptive all the way down: building responsive materials from hierarchies of chemomechanical feedback.

    Science.gov (United States)

    Grinthal, Alison; Aizenberg, Joanna

    2013-09-07

    A living organism is a bundle of dynamic, integrated adaptive processes: not only does it continuously respond to constant changes in temperature, sunlight, nutrients, and other features of its environment, but it does so by coordinating hierarchies of feedback among cells, tissues, organs, and networks all continuously adapting to each other. At the root of it all is one of the most fundamental adaptive processes: the constant tug of war between chemistry and mechanics that interweaves chemical signals with endless reconfigurations of macromolecules, fibers, meshworks, and membranes. In this tutorial we explore how such chemomechanical feedback - as an inherently dynamic, iterative process connecting size and time scales - can and has been similarly evoked in synthetic materials to produce a fascinating diversity of complex multiscale responsive behaviors. We discuss how chemical kinetics and architecture can be designed to generate stimulus-induced 3D spatiotemporal waves and topographic patterns within a single bulk material, and how feedback between interior dynamics and surface-wide instabilities can further generate higher order buckling and wrinkling patterns. Building on these phenomena, we show how yet higher levels of feedback and spatiotemporal complexity can be programmed into hybrid materials, and how these mechanisms allow hybrid materials to be further integrated into multicompartmental systems capable of hierarchical chemo-mechano-chemical feedback responses. These responses no doubt represent only a small sample of the chemomechanical feedback behaviors waiting to be discovered in synthetic materials, and enable us to envision nearly limitless possibilities for designing multiresponsive, multifunctional, self-adapting materials and systems.

  12. Response to events involving the inadvertent movement or illicit trafficking of radioactive materials

    International Nuclear Information System (INIS)

    2004-08-01

    By international agreements, the movement of all radioactive materials within and between States should be subject to high standards of regulatory, administrative, safety and engineering controls to ensure that such movements are conducted in a safe and secure manner. In the case of nuclear materials, there are additional requirements for physical protection and accountability to ensure against threats of nuclear proliferation and to safeguard against any attempts at diversion. The results of the terrorist attacks of September 2001 emphasized the requirement for enhanced control and security of nuclear and radioactive materials. In this regard, measures are being taken to increase the global levels of physical protection and security for nuclear materials. Experience in many parts of the world continues to prove that movements of radioactive materials outside of the regulatory and legal frameworks continue to occur. Such movements may be either deliberate or inadvertent. Deliberate, illegal movements of radioactive materials, including nuclear material, for terrorist, political or illegal profit is generally understood to be illicit trafficking. The more common movements outside of regulatory control are inadvertent in nature. An example of an inadvertent movement might be the transport of steel contaminated by a melted radioactive source that was lost from proper controls. Such a shipment may present health and safety threats to the personnel involved as well as to the general public. States have the responsibility for combating illicit trafficking and inadvertent movements of radioactive materials. The IAEA co-operates with Member States and other international organizations in joint efforts to prevent incidents of illicit trafficking and inadvertent movements and to harmonize policies and measures by the provision of relevant advice through technical assistance and documents. As an example, the IAEA and the World Customs Organization (WCO) maintain a Memorandum

  13. Response to events involving the inadvertent movement or illicit trafficking of radioactive materials

    International Nuclear Information System (INIS)

    2002-09-01

    By international agreements, the movement of all radioactive materials within and between States should be subject to high standards of regulatory, administrative, safety and engineering controls to ensure that such movements are conducted in a safe and secure manner. In the case of nuclear materials, there are additional requirements for physical protection and accountability to ensure against threats of nuclear proliferation and to safeguard against any attempts at diversion. The results of the terrorist attacks of September 2001 emphasized the requirement for enhanced control and security of nuclear and radioactive materials. In this regard, measures are being taken to increase the global levels of physical protection and security for nuclear materials. Experience in many parts of the world continues to prove that movements of radioactive materials outside of the regulatory and legal frameworks continue to occur. Such movements may be either deliberate or inadvertent. Deliberate, illegal movements of radioactive materials, including nuclear material, for terrorist, political or illegal profit is generally understood to be illicit trafficking. The more common movements outside of regulatory control are inadvertent in nature. An example of an inadvertent movement might be the transport of steel contaminated by a melted radioactive source that was lost from proper controls. Such a shipment may present health and safety threats to the personnel involved as well as to the general public. States have the responsibility for combating illicit trafficking and inadvertent movements of radioactive materials. The IAEA co-operates with Member States and other international organizations in joint efforts to prevent incidents of illicit trafficking and inadvertent movements and to harmonize policies and measures by the provision of relevant advice through technical assistance and documents. As an example, the IAEA and the World Customs Organization (WCO) maintain a Memorandum

  14. Response to events involving the inadvertent movement or illicit trafficking of radioactive materials

    International Nuclear Information System (INIS)

    2002-08-01

    By international agreements, the movement of all radioactive materials within and between States should be subject to high standards of regulatory, administrative, safety and engineering controls to ensure that such movements are conducted in a safe and secure manner. In the case of nuclear materials, there are additional requirements for physical protection and accountability to ensure against threats of nuclear proliferation and to safeguard against any attempts at diversion. The results of the terrorist attacks of September 2001 emphasized the requirement for enhanced control and security of nuclear and radioactive materials. In this regard, measures are being taken to increase the global levels of physical protection and security for nuclear materials. Experience in many parts of the world continues to prove that movements of radioactive materials outside of the regulatory and legal frameworks continue to occur. Such movements may be either deliberate or inadvertent. Deliberate, illegal movements of radioactive materials, including nuclear material, for terrorist, political or illegal profit is generally understood to be illicit trafficking. The more common movements outside of regulatory control are inadvertent in nature. An example of an inadvertent movement might be the transport of steel contaminated by a melted radioactive source that was lost from proper controls. Such a shipment may present health and safety threats to the personnel involved as well as to the general public. States have the responsibility for combating illicit trafficking and inadvertent movements of radioactive materials. The IAEA co-operates with Member States and other international organizations in joint efforts to prevent incidents of illicit trafficking and inadvertent movements and to harmonize policies and measures by the provision of relevant advice through technical assistance and documents. As an example, the IAEA and the World Customs Organization (WCO) maintain a Memorandum

  15. Response to events involving the inadvertent movement or illicit trafficking of radioactive materials

    International Nuclear Information System (INIS)

    2003-08-01

    By international agreements, the movement of all radioactive materials within and between States should be subject to high standards of regulatory, administrative, safety and engineering controls to ensure that such movements are conducted in a safe and secure manner. In the case of nuclear materials, there are additional requirements for physical protection and accountability to ensure against threats of nuclear proliferation and to safeguard against any attempts at diversion. The results of the terrorist attacks of September 2001 emphasized the requirement for enhanced control and security of nuclear and radioactive materials. In this regard, measures are being taken to increase the global levels of physical protection and security for nuclear materials. Experience in many parts of the world continues to prove that movements of radioactive materials outside of the regulatory and legal frameworks continue to occur. Such movements may be either deliberate or inadvertent. Deliberate, illegal movements of radioactive materials, including nuclear material, for terrorist, political or illegal profit is generally understood to be illicit trafficking. The more common movements outside of regulatory control are inadvertent in nature. An example of an inadvertent movement might be the transport of steel contaminated by a melted radioactive source that was lost from proper controls. Such a shipment may present health and safety threats to the personnel involved as well as to the general public. States have the responsibility for combating illicit trafficking and inadvertent movements of radioactive materials. The IAEA co-operates with Member States and other international organizations in joint efforts to prevent incidents of illicit trafficking and inadvertent movements and to harmonize policies and measures by the provision of relevant advice through technical assistance and documents. As an example, the IAEA and the World Customs Organization (WCO) maintain a Memorandum

  16. Next generation, in-situ microfluidic flow control using stimuli responsive materials for biomemetic microfluicic platforms

    NARCIS (Netherlands)

    Coleman, Simon; Azouz, Aymen Ben; Schiphorst, Jeroen Ter; Saez, Janire; Whyte, Jeffrey; McCluskey, Peter; Kent, Nigel; Benito-Lopez, Fernando; Schenning, Albert; Diamond, Dermot

    2016-01-01

    The requirement of significant off-chip fluid manipulation using high-cost mechanical components has resulted in design limitations in microfluidic devices. We report the use of novel stimuli responsive polymer gel materials for a variety of bio-inspired processes to achieve in-situ microfluidic

  17. The influence of parent material on vegetation response 15 years after the Dude Fire, Arizona

    Science.gov (United States)

    Jackson M. Leonard; Alvin L. Medina; Daniel G. Neary; Aregai Tecle

    2015-01-01

    This study examined the effects of two types of parent material, sandstone and limestone, on the response of vegetation growth after the 1990 Dude Fire in central Arizona. The operating hypothesis of the study was that, given the right conditions, severe wildfire can trigger vegetation type conversion. Overall, three patterns emerged: (1) oak density increased by 413%...

  18. A measurement of the response to fast neutrons of several materials dosemeters

    International Nuclear Information System (INIS)

    Jones, L.T.; Kitching, S.J.; Lewis, T.A.; Playle, T.S.

    1986-07-01

    The response to fast neutrons was measured for three types of materials testing dosemeters: fast neutron dosimetry silicon diodes; beryllia, alumina and calcium fluoride TLDs; graphite walled ionisation chambers. The calibrations were made using a 3MW positive ion accelerator. The arrangement of the target, beam monitor and devices is described, and the measured fast neutron sensitivities are presented. (UK)

  19. Costs for insurance of civil responsibility for nuclear damage during transportation of nuclear materials

    International Nuclear Information System (INIS)

    Amelina, M.E.; Arsent'ev, S.V.; Molchanov, A.S.

    2009-01-01

    The article considers the method of calculation of rates for insurance of civil responsibility for nuclear damage during transportation of nuclear materials, which can minimize the insurer's costs for this type of insurance in situation when there is no statistics available and it is not possible to calculate the insurance rate by the traditional means using the probability theory

  20. The role of supramolecular chemistry in stimuli responsive and hierarchically structured functional organic materials

    NARCIS (Netherlands)

    Schenning, A.P.H.J.; Bastiaansen, C.W.M.; Broer, D.J.; Debije, M.G.

    2014-01-01

    ABSTRACT: In this review, we show the important role of supramolecular chemistry in the fabrication of stimuli responsive and hierarchically structured liquid crystalline polymer networks. Supramolecular interactions can be used to create three dimensional order or as molecular triggers in materials

  1. Prediction of elastic-plastic response of structural elements subjected to cyclic loading

    International Nuclear Information System (INIS)

    El Haddad, M.H.; Samaan, S.

    1985-01-01

    A simplified elastic-plastic analysis is developed to predict stress strain and force deformation response of structural metallic elements subjected to irregular cyclic loadings. In this analysis a simple elastic-plastic method for predicting the skeleton force deformation curve is developed. In this method, elastic and fully plastic solutions are first obtained for unknown quantities, such as deflection or local strains. Elastic and fully plastic contributions are then combined to obtain an elastic-plastic solution. The skeleton curve is doubled to establish the shape of the hysteresis loop. The complete force deformation response can therefore be simulated through reversal by reversal in accordance with hysteresis looping and material memory. Several examples of structural elements with various cross sections made from various materials and subjected to irregular cyclic loadings, are analysed. A close agreement is obtained between experimental results found in the literature and present predictions. (orig.)

  2. Development on inelastic analysis acceptance criteria for radioactive material transportation packages

    International Nuclear Information System (INIS)

    Ammerman, D.J.; Ludwigsen, J.S.

    1995-01-01

    The response of radioactive material transportation packages to mechanical accident loadings can be more accurately characterized by non-linear dynamic analysis than by the ''Equivalent dynamic'' static elastic analysis typically used in the design of these packages. This more accurate characterization of the response can lead to improved package safety and design efficiency. For non-linear dynamic analysis to become the preferred method of package design analysis, an acceptance criterion must be established that achieves an equivalent level of safety as the currently used criterion defined in NRC Regulatory Guide 7.6 (NRC 1978). Sandia National Laboratories has been conducting a study of possible acceptance criteria to meet this requirement. In this paper non-linear dynamic analysis acceptance criteria based on stress, strain, and strain-energy-density will be discussed. An example package design will be compared for each of the design criteria, including the approach of NRC Regulatory Guide 7.6

  3. Irradiated stainless steel material constitutive model for use in the performance evaluation of PWR pressure vessel internals

    Energy Technology Data Exchange (ETDEWEB)

    Rashid, J.Y.; Dunham, R.S. [ANATECH (United States); Demma, A. [Electric Power Research Institute - EPRI (United States)

    2011-07-01

    Demonstration of component functionality requires analytical simulations of reactor internals behavior. Towards that aim, EPRI has undertaken the development of irradiated material constitutive model and damage criteria for use in global and local finite-element based functionality analysis methodology. The constitutive behavioral regimes of irradiated stainless steel types 316 and 304 materials included in the model consist of: elastic-plastic material response considering irradiation hardening of the stress-strain curve, irradiation creep, stress relaxation, and void swelling. IASCC and degradation of ductility with irradiation are the primary damage mechanisms considered in the model. The material behavior model development consists of two parts: the first part is a user-material subroutine that can interface with a general-purpose finite element computer program to adapt it to the special-purpose of functionality analysis of reactor internals. The second part is a user utility in the form of Excel Spread sheets that permit users to extract a given property, e.g. the elastic-plastic stress-strain curve, creep curve, or void-swelling curve, as function of the relevant independent variables. The development of the model takes full advantage of the significant work that has been undertaken within EPRI's Material Reliability Program (MRP) to improve the knowledge of the material properties of irradiated stainless steels. Data from EPRI's MRP database have been utilized to develop equations that characterize the yield strength, ultimate tensile strength, uniform elongation, total elongation, reduction in area, void swelling and irradiation creep of stainless steels in a PWR environment. It is noted that, while the development of the model's equations has been statistically faithful to the material database, approximations were introduced in the model to ensure appropriate conservatism in the model's application consistently with accepted

  4. Temporal response methods for dynamic measurement of in-process inventory of dissolved nuclear materials

    International Nuclear Information System (INIS)

    Ziri, S.M.; Seefeldt, W.B.

    1977-08-01

    This analysis has demonstrated that a plant's temporal response to perturbation of feed isotope composition can be used to measure the in-process inventory, without suspending plant operations. The main advantages of the temporal response technique over the step-displacement method are (1) it (the temporal response method) obviates the need for large special feed batches, and (2) it obviates the requirement that all the in-process material have a uniform isotopic composition at the beginning of the measurement. The temporal response method holds promise for essentially continuous real-time determination of in-process SNM. However, the temporal response method requires the measurement of the isotopic composition of many samples, and it works best for a stationary random input time series of tracer perturbations. Both of these requirements appear amenable to satisfaction by practical equipment and procedures if the benefits are deemed sufficiently worthwhile

  5. Comparison of elastic and inelastic seismic response of high temperature piping systems

    International Nuclear Information System (INIS)

    Thomas, F.M.; McCabe, S.L.; Liu, Y.

    1994-01-01

    A study of high temperature power piping systems is presented. The response of the piping systems is determined when subjected to seismic disturbances. Two piping systems are presented, a main steam line, and a cold reheat line. Each of the piping systems are modeled using the ANSYS computer program and two analyses are performed on each piping system. First, each piping system is subjected to a seismic disturbance and the pipe material is assumed to remain linear and elastic. Next the analysis is repeated for each piping system when the pipe material is modeled as having elastic-plastic behavior. The results of the linear elastic analysis and elastic-plastic analysis are compared for each of the two pipe models. The pipe stresses, strains, and displacements, are compared. These comparisons are made so that the effect of the material yielding can be determined and to access what error is made when a linear analysis is performed on a system that yields

  6. Non-local spatial frequency response of photopolymer materials containing chain transfer agents: I. Theoretical modelling

    International Nuclear Information System (INIS)

    Guo, Jinxin; Gleeson, Michael R; Liu, Shui; Sheridan, John T

    2011-01-01

    The non-local photopolymerization driven diffusion (NPDD) model predicts that a reduction in the non-local response length within a photopolymer material will improve its high spatial frequency response. The introduction of a chain transfer agent reduces the average molecular weight of polymer chains formed during free radical polymerization. Therefore a chain transfer agent (CTA) provides a practical method to reduce the non-local response length. An extended NPDD model is presented, which includes the chain transfer reaction and most major photochemical processes. The addition of a chain transfer agent into an acrylamide/polyvinyl alcohol photopolymer material is simulated and the predictions of the model are examined. The predictions of the model are experimentally examined in part II of this paper

  7. Pyrolysis responses of kevlar/epoxy composite materials on laser irradiating

    Science.gov (United States)

    Liu, Wei-ping; Wei, Cheng-hua; Zhou, Meng-lian; Ma, Zhi-liang; Song, Ming-ying; Wu, Li-xiong

    2017-05-01

    The pyrolysis responses of kevlar/epoxy composite materials are valuable to study in a case of high temperature rising rate for its widely application. Distinguishing from the Thermal Gravimetric Analysis method, an apparatus is built to research the pyrolysis responses of kevlar/epoxy composite materials irradiated by laser in order to offer a high temperature rising rate of the sample. By deploying the apparatus, a near real-time gas pressure response can be obtained. The sample mass is weighted before laser irradiating and after an experiment finished. Then, the gas products molecular weight and the sample mass loss evolution are derived. It is found that the pressure and mass of the gas products increase with the laser power if it is less than 240W, while the molecular weight varies inversely. The variation tendency is confusing while the laser power is bigger than 240W. It needs more deeper investigations to bring it to light.

  8. Stress-Strain Analysis in TiN Nanocoating Deposited on Polymer with respect to Au Nanointerlayer

    Directory of Open Access Journals (Sweden)

    Magdalena Kopernik

    2014-01-01

    Full Text Available The multiscale analysis in the authors’ finite element code confirmed possibility of fracture, because of not sufficiently high level of compressive residual stress in the TiN deposited by physical deposition method and varied mechanical properties of the thin film and substrate. The residual stress cannot be identified by X-ray technique for amorphous polymer and layer with domains of crystalline TiN. It is assumed that the buffer biocompatible thin film of Au in the TiN/Bionate II material system will alter the evolution of residual stress and, therefore, will allow to determine the residual stress in profilometry studies, and helps to improve toughness of the connection between TiN and Bionate II. The introduction of Au nanocoating in the material system results in bending of the sample and a compressive residual stress in the TiN coating. Results of finite element simulation show improvement of connection between the polymer and TiN, and an increase of compressive residual stress in the coating by introduction of Au nanointerlayer results in reduction of stress and strain in the substrate (close to the boundary between substrate and coating.

  9. Magneto-electro-responsive material based on magnetite nanoparticles/polyurethane composites

    Energy Technology Data Exchange (ETDEWEB)

    Petcharoen, Karat; Sirivat, Anuvat, E-mail: anuvat.s@chula.ac.th

    2016-04-01

    Multi-functional materials in actuator applications have been developed toward reversibility and sensitivity under various actuating fields. In this work, magneto-electro-responsive materials consisting of a polyurethane (PU) matrix and its composites embedded with magnetite nanoparticles (MNP) as a dispersed phase were fabricated to tailor the electromechanical properties and bending performance under electric, magnetic, and electromagnetic fields. Due to the superior characteristics of MNP over other magnetic materials, the composites fabricated with electronic polarization were highly responsive under electric field. The highest storage modulus sensitivity belonged to the 1.0% v/v MNP/PU composite which possessed the value of 3.46 at the electric field 2 kV mm{sup −1}. Moreover, all of the PU composites behaved as an electrostrictive material in which the stress depended quadratically on the electric field. It was demonstrated that the PU composites also possessed very good recoverability, fast response (< 15 s) and large bending angle relative to that of pristine PU under applied electric field. Interestingly, the steady state storage modulus response was attained within the first electrical actuation cycle and the PU composite was a fully reversible material. In addition, it was shown that superparamagnetism was a common characteristic of all fabricated composites under magnetic field. The 3.0%v/v MNP/PU composite provided the largest bending distance up to 23.60 mm, and 14.10 mm under the magnetic field of 5000 G, and the electromagnetic field of 320 G, respectively. In summary, the MNP/PU composite material is a potential candidate to be used as a smart material under the influences of electric and/or magnetic fields over other existing dielectric materials. - Highlights: • MNP/PU composites exhibit a superparamagnetic behavior. • MNP/PU composites show full reversibility under electric field. • 1.0% v/v MNP/PU composite provides the highest

  10. Magneto-electro-responsive material based on magnetite nanoparticles/polyurethane composites

    International Nuclear Information System (INIS)

    Petcharoen, Karat; Sirivat, Anuvat

    2016-01-01

    Multi-functional materials in actuator applications have been developed toward reversibility and sensitivity under various actuating fields. In this work, magneto-electro-responsive materials consisting of a polyurethane (PU) matrix and its composites embedded with magnetite nanoparticles (MNP) as a dispersed phase were fabricated to tailor the electromechanical properties and bending performance under electric, magnetic, and electromagnetic fields. Due to the superior characteristics of MNP over other magnetic materials, the composites fabricated with electronic polarization were highly responsive under electric field. The highest storage modulus sensitivity belonged to the 1.0% v/v MNP/PU composite which possessed the value of 3.46 at the electric field 2 kV mm"−"1. Moreover, all of the PU composites behaved as an electrostrictive material in which the stress depended quadratically on the electric field. It was demonstrated that the PU composites also possessed very good recoverability, fast response (< 15 s) and large bending angle relative to that of pristine PU under applied electric field. Interestingly, the steady state storage modulus response was attained within the first electrical actuation cycle and the PU composite was a fully reversible material. In addition, it was shown that superparamagnetism was a common characteristic of all fabricated composites under magnetic field. The 3.0%v/v MNP/PU composite provided the largest bending distance up to 23.60 mm, and 14.10 mm under the magnetic field of 5000 G, and the electromagnetic field of 320 G, respectively. In summary, the MNP/PU composite material is a potential candidate to be used as a smart material under the influences of electric and/or magnetic fields over other existing dielectric materials. - Highlights: • MNP/PU composites exhibit a superparamagnetic behavior. • MNP/PU composites show full reversibility under electric field. • 1.0% v/v MNP/PU composite provides the highest sensitivity

  11. A study of binder materials subjected to isentropic compression loading

    International Nuclear Information System (INIS)

    Hall, Clint Allen; Orler, E. Bruce; Sheffield, Steve A.; Gustavsen, Rick L.; Sutherland, Gerrit; Baer, Melvin R.; Hooks, D.E.

    2005-01-01

    Binders such as Estane, Teflon, Kel F and HTPB are typically used in heterogeneous explosives to bond polycrystalline constituents together as an energetic composite. Combined theoretical and experimental studies are underway to unravel the mechanical response of these materials when subjected to isentropic compression loading. Key to this effort is the determination of appropriate constitutive and EOS property data at extremely high stress-strain states as required for detailed mesoscale modeling. The Sandia Z accelerator and associated diagnostics provides new insights into mechanical response of these nonreactive constituents via isentropic ramp-wave compression loading. Several thicknesses of samples, varied from 0.3 to 1.2 mm, were subjected to a ramp load of ∼42 Kbar over 500 ns duration using the Sandia Z-machine. Profiles of transmitted ramp waves were measured at window interfaces using conventional VISAR. Shock physics analysis is then used to determine the nonlinear material response of the binder materials. In this presentation we discuss experimental and modeling details of the ramp wave loading ICE experiments designed specifically for binder materials.

  12. Importance diagrams - a novel presentation of the response of a material to neutron irradiation

    International Nuclear Information System (INIS)

    Forrest, R.A.

    1998-01-01

    Activation of fusion materials following neutron irradiation is of great technological importance, especially in the study of safety and environmental impacts. Currently, activation calculations are performed for a particular neutron spectrum, appropriate to a region in a particular fusion device, which makes it difficult to extract generic information. The present work gives details of a method to present the dominant nuclides for the radiological responses or an irradiated material in a fashion that is independent of the neutron spectrum and almost independent of the flux. The importance diagrams show regions in the decay time versus neutron energy space where a nuclide contributes >50% of the response. The importance diagrams for pure iron and SS316 are described, and it is noted that the shapes of the various regions vary very little with the total neutron flux. Variation of the diagrams with irradiation time occurs at short decay times in a systematic fashion. The use of the diagrams in a realistic spectrum relies on an expansion, which while not generally true, does hold approximately for many of the nuclides of interest. The diagrams are therefore a valuable summary of the universal, device-independent, response of the materials, and when combined with pathway information give a comprehensive description of activation for that material. (orig.)

  13. Initial rigid response and softening transition of highly stretchable kirigami sheet materials.

    Science.gov (United States)

    Isobe, Midori; Okumura, Ko

    2016-04-27

    We study, experimentally and theoretically, the mechanical response of sheet materials on which line cracks or cuts are arranged in a simple pattern. Such sheet materials, often called kirigami (the Japanese words, kiri and gami, stand for cut and paper, respectively), demonstrate a unique mechanical response promising for various engineering applications such as stretchable batteries: kirigami sheets possess a mechanical regime in which sheets are highly stretchable and very soft compared with the original sheets without line cracks, by virtue of out-of-plane deformation. However, this regime starts after a transition from an initial stiff regime governed by in-plane deformation. In other words, the softness of the kirigami structure emerges as a result of a transition from the two-dimensional to three-dimensional deformation, i.e., from stretching to bending. We clarify the physical origins of the transition and mechanical regimes, which are revealed to be governed by simple scaling laws. The results could be useful for controlling and designing the mechanical response of sheet materials including cell sheets for medical regeneration and relevant to the development of materials with tunable stiffness and mechanical force sensors.

  14. Viscoplastic Constitutive Theory Demonstrated for Monolithic Ceramic Materials

    Science.gov (United States)

    Janosik, Lesley A.

    1999-01-01

    Development of accurate three-dimensional (multiaxial) inelastic stress-strain models is critical in utilizing advanced ceramics for challenging 21st century high-temperature structural applications. The current state of the art uses elastic stress fields as a basis for both subcritical crack growth and creep life prediction efforts aimed at predicting the time dependent reliability response of ceramic components subjected to elevated service temperatures. However, to successfully design components that will meet tomorrow's challenging requirements, design engineers must recognize that elastic predictions are inaccurate for these materials when subjected to high-temperature service conditions such as those encountered in advanced heat engine components. Analytical life prediction methodologies developed for advanced ceramics and other brittle materials must employ accurate constitutive models that capture the inelastic response exhibited by these materials at elevated service temperatures. A constitutive model recently developed at the NASA Lewis Research Center helps address this issue by accounting for the time-dependent (inelastic) material deformation phenomena (e.g., creep, rate sensitivity, and stress relaxation) exhibited by monolithic ceramics exposed to high-temperature service conditions. In addition, the proposed formulation is based on a threshold function that is sensitive to hydrostatic stress and allows different behavior in tension and compression, reflecting experimental observations obtained for these material systems.

  15. Extrinsic response enhancement at the polymorphic phase boundary in piezoelectric materials

    Energy Technology Data Exchange (ETDEWEB)

    Ochoa, Diego A.; García, José E., E-mail: jose.eduardo.garcia@upc.edu [Department of Physics, Universitat Politècnica de Catalunya - BarcelonaTech, Barcelona 08034 (Spain); Esteves, Giovanni; Jones, Jacob L. [Department of Materials Science and Engineering, North Carolina State University, Raleigh, North Carolina 27696 (United States); Rubio-Marcos, Fernando; Fernández, José F. [Department of Electroceramics, Instituto de Cerámica y Vidrio - CSIC, Madrid 28049 (Spain)

    2016-04-04

    Polymorphic phase boundaries (PPBs) in piezoelectric materials have attracted significant interest in recent years, in particular, because of the unique properties that can be found in their vicinity. However, to fully harness their potential as micro-nanoscale functional entities, it is essential to achieve reliable and precise control of their piezoelectric response, which is due to two contributions known as intrinsic and extrinsic. In this work, we have used a (K,Na)NbO{sub 3}-based lead-free piezoceramic as a model system to investigate the evolution of the extrinsic contribution around a PPB. X-ray diffraction measurements are performed over a wide range of temperatures in order to determine the structures and transitions. The relevance of the extrinsic contribution at the PPB region is evaluated by means of nonlinear dielectric response measurements. Though it is widely appreciated that certain intrinsic properties of ferroelectric materials increase as PPBs are approached, our results demonstrate that the extrinsic contribution also maximizes. An enhancement of the extrinsic contribution is therefore also responsible for improving the functional properties at the PPB region. Rayleigh's law is used to quantitatively analyze the nonlinear response. As a result, an evolution of the domain wall motion dynamics through the PPB region is detected. This work demonstrates that the extrinsic contribution at a PPB may have a dynamic role in lead-free piezoelectric materials, thereby exerting a far greater influence on their functional properties than that considered to date.

  16. Dangerous quantities of radioactive material (D-values). Emergency preparedness and response. Publication date: August 2006

    International Nuclear Information System (INIS)

    2006-08-01

    Radioactive material is widely used in industry, medicine, education and agriculture. In addition, it occurs naturally. The health risk posed by these materials vary widely depending on many factors, the most important of which are the amount of the material involved and its physical and chemical form. Therefore, there is a need to identify the quantity and type of radioactive material for which emergency preparedness and other arrangements (e.g. security) are warrant due to the health risk they pose. The aim of this publication is to provide practical guidance for Member States on that quantity of radioactive material that may be considered dangerous. A dangerous quantity is that, which if uncontrolled, could be involved in a reasonable scenario resulting in the death of an exposed individual or a permanent injury, which decreases that person's quality of life. This publication is published as part of the IAEA Emergency Preparedness and Response Series. It supports several publications including: the IAEA Safety Requirements 'Preparedness and Response for a Nuclear or Radiological Emergency', IAEA Safety Standards Series No. GS-R-2. IAEA, Vienna (2002); IAEA Safety Guide 'Categorization of Radioactive Sources', IAEA Safety Standards Series No RS-G-1.9, IAEA, Vienna (2005) and IAEA Safety Guide 'Arrangements for Preparedness for a Nuclear or Radiological Emergency' IAEA Safety Standards Series No. GS-G-2.1, IAEA, Vienna (2006). The procedures and data in this publication have been prepared with due attention to accuracy. However, as part of the review process, they undergo ongoing quality assurance checks. Comments are welcome and, following a period that will allow for a more extensive review, the IAEA may revise this publication as part of the process of continuous improvement. The publication uses a number of exposure scenarios, risk models and dosimetric data, which could be used during the response to nuclear or radiological emergency or other purposes

  17. Temporal response methods for dynamic measurement of in-process inventory of dissolved nuclear materials

    International Nuclear Information System (INIS)

    Zivi, S.M.; Seefeldt, W.B.

    1976-01-01

    This analysis demonstrated that a plant's temporal response to perturbations of feed isotope composition can be used to measure the in-process inventory, without suspending plant operations. The main advantage of the temporal response technique over the step-displacement method are (1) it obviates the need for large special feed batches and (2) it obviates the requirement that all the in-process material have a uniform isotopic composition at the beginning of the measurement. The temporal response method holds promise for essentially continuous real-time determination of in-process SNM. The main disadvantage or problem with the temporal response method is that it requires the measurement of the isotopic composition of a great many samples to moderately high accuracy. This requirement appears amenable to solution by a modest effort in instrument development

  18. Severe deterministic effects of external exposure and intake of radioactive material: basis for emergency response criteria

    International Nuclear Information System (INIS)

    Kutkov, V; Buglova, E; McKenna, T

    2011-01-01

    Lessons learned from responses to past events have shown that more guidance is needed for the response to radiation emergencies (in this context, a 'radiation emergency' means the same as a 'nuclear or radiological emergency') which could lead to severe deterministic effects. The International Atomic Energy Agency (IAEA) requirements for preparedness and response for a radiation emergency, inter alia, require that arrangements shall be made to prevent, to a practicable extent, severe deterministic effects and to provide the appropriate specialised treatment for these effects. These requirements apply to all exposure pathways, both internal and external, and all reasonable scenarios, to include those resulting from malicious acts (e.g. dirty bombs). This paper briefly describes the approach used to develop the basis for emergency response criteria for protective actions to prevent severe deterministic effects in the case of external exposure and intake of radioactive material.

  19. Emergency response capabilities developed in the United States to deal with nuclear materials transportation accidents

    International Nuclear Information System (INIS)

    Vandevender, S.G.; Reese, R.T.; Schilling, A.H.

    1980-01-01

    The non-existence of emergency response programs is frequently stated as a reason for restricting the movement of radioactive materials through states or local jurisdictions. Yet, studies discussed here indicate that emergency response capability, while not in the best condition, is getting more money, interest and attention, and in most states response networks exist which could be effective in responding to radiological emergencies. Awareness of such capabilities by the public is an important feature in increasing the public's confidence in the ability of federal, state and local officials in controlling hazards. One aspect of this awareness program could be in broader availability of radioactive emergency techniques for possible first responders to emergencies. This training, public awareness and more emphasis on workable emergency plans will help to assure reliable and workable emergency response plans

  20. Prediction of macroscopic and local stress-strain behaviors of perforated plates under primary and secondary creep conditions

    International Nuclear Information System (INIS)

    Igari, Toshihide; Tokiyoshi, Takumi; Mizokami, Yorikata

    2000-01-01

    Prediction methods of macroscopic and local creep behaviors of perforated plates are examined in order to apply these methods to the structural design of perforated structures such as heat exchangers used in elevated temperatures. Both primary and secondary creeps are considered for predicting macroscopic and local creep behaviors of perorated plates which are made of actual structural materials. Both uniaxial and multiaxial loading of perforated plates are taken into consideration. The concept of effective stress is applied to the prediction of macroscopic creep behaviors of perforated plates, and the predicted results are compared with the numerical results by FEM for the unit section of perorated plated under creep, in order to confirm the propriety of the proposed method. Based on the idea that stress exponents in creep equations govern the stress distribution of perforated plates, a modified Neuber's rule is used for predicting local stress and strain concentrations. The propriety of this prediction method is shown through a comparison of the prediction with the numerical results by FEM for the unit section of perforated plates under creep, and experimental results by the Moire method. (author)

  1. Material properties characterization - concrete

    International Nuclear Information System (INIS)

    England, G.L.; MacLeod, J.S.

    1978-01-01

    A review is presented of the six contributions in the SMiRT 4 conference to Session H5 on structural analysis of prestressed concrete reactor pressure vessels. These relate to short term stress-strain aspects of concrete loaded beyond the linear range in uniaxial and biaxial stress fields, to some time and temperature dependent properties of concrete at working stress levels, and to a programme of strain-gauge testing for the assessment of concrete properties. From the information discussed, it is clear that there are difficulties in determining material properties for concrete, and these are summarised. (UK)

  2. Empirical Model Development for Predicting Shock Response on Composite Materials Subjected to Pyroshock Loading

    Science.gov (United States)

    Gentz, Steven J.; Ordway, David O; Parsons, David S.; Garrison, Craig M.; Rodgers, C. Steven; Collins, Brian W.

    2015-01-01

    The NASA Engineering and Safety Center (NESC) received a request to develop an analysis model based on both frequency response and wave propagation analyses for predicting shock response spectrum (SRS) on composite materials subjected to pyroshock loading. The model would account for near-field environment (approx. 9 inches from the source) dominated by direct wave propagation, mid-field environment (approx. 2 feet from the source) characterized by wave propagation and structural resonances, and far-field environment dominated by lower frequency bending waves in the structure. This report documents the outcome of the assessment.

  3. Development of supporting system for emergency response to maritime transport accidents involving radioactive material

    International Nuclear Information System (INIS)

    Odano, N.; Matsuoka, T.; Suzuki, H.

    2004-01-01

    National Maritime Research Institute has developed a supporting system for emergency response of competent authority to maritime transport accidents involving radioactive material. The supporting system for emergency response has functions of radiation shielding calculation, marine diffusion simulation, air diffusion simulation and radiological impact evaluation to grasp potential hazard of radiation. Loss of shielding performance accident and loss of sealing ability accident were postulated and impact of the accidents was evaluated based on the postulated accident scenario. Procedures for responding to emergency were examined by the present simulation results

  4. Semi-analytical solution for electro-magneto-thermoelastic creep response of functionally graded piezoelectric rotating disk

    International Nuclear Information System (INIS)

    Loghman, A.; Abdollahian, M.; Jafarzadeh Jazi, A.; Ghorbanpour Arani, A.

    2013-01-01

    Time-dependent electro-magneto-thermoelastic creep response of rotating disk made of functionally graded piezoelectric materials (FGPM) is studied. The disk is placed in a uniform magnetic and a distributed temperature field and is subjected to an induced electric potential and a centrifugal body force. The material thermal, mechanical, magnetic and electric properties are represented by power-law distributions in radial direction. The creep constitutive model is Norton's law in which the creep parameters are also power functions of radius. Using equations of equilibrium, strain-displacement and stress-strain relations in conjunction with the potential-displacement equation a non-homogeneous differential equation containing time-dependent creep strains for displacement is derived. A semi-analytical solution followed by a numerical procedure has been developed to obtain history of stresses, strains, electric potential and creep-strain rates by using Prandtl-Reuss relations. History of electric potential, Radial, circumferential and effective stresses and strains as well as the creep stress rates and effective creep strain rate histories are presented. It has been found that tensile radial stress distribution decreases during the life of the FGPM rotating disk which is associated with major electric potential redistributions which can be used as a sensor for condition monitoring of the FGPM rotating disk. (authors)

  5. Food and Natural Materials Target Mechanisms to Effectively Regulate Allergic Responses.

    Science.gov (United States)

    Shin, Hee Soon; Shon, Dong-Hwa

    2015-01-01

    An immune hypersensitivity disorder called allergy is caused by diverse allergens entering the body via skin contact, injection, ingestion, and/or inhalation. These allergic responses may develop into allergic disorders, including inflammations such as atopic dermatitis, asthma, anaphylaxis, food allergies, and allergic rhinitis. Several drugs have been developed to treat these allergic disorders; however, long-term intake of these drugs could have adverse effects. As an alternative to these medicines, food and natural materials that ameliorate allergic disorder symptoms without producing any side effects can be consumed. Food and natural materials can effectively regulate successive allergic responses in an allergic chain-reaction mechanism in the following ways: [1] Inhibition of allergen permeation via paracellular diffusion into epithelial cells, [2] suppression of type 2 T-helper (Th) cell-related cytokine production by regulating Th1/Th2 balance, [3] inhibition of pathogenic effector CD4(+) T cell differentiation by inducing regulatory T cells (Treg), and [4] inhibition of degranulation in mast cells. The immunomodulatory effects of food and natural materials on each target mechanism were scientifically verified and shown to alleviate allergic disorder symptoms. Furthermore, consumption of certain food and natural materials such as fenugreek, skullcap, chitin/chitosan, and cheonggukjang as anti-allergics have merits such as safety (no adverse side effects), multiple suppressive effects (as a mixture would contain various components that are active against allergic responses), and ease of consumption when required. These merits and anti-allergic properties of food and natural materials help control various allergic disorders.

  6. Preliminary study on the forgeability and heat treatment response of niobium - containing tool steels materials

    International Nuclear Information System (INIS)

    Cescon, T.; Papaleo, R.

    1981-01-01

    The forgeability and microstructure of tool steels materials based on the M-2 composition, where W and V were partially replaced by Nb, were examined. The optimum heat-treating conditions were established. The poor response to heat treatment of some of the alloys studied indicated the need of increasing the C content of the steels when Nb is used as a substitute for W and V. (Author) [pt

  7. Technical considerations for detection of and response to illicit trafficking in radioactive materials

    International Nuclear Information System (INIS)

    Duftschmid, K.E.; Arlt, R.; Cunningham, J.; Gayral, J.P.; Kravchenko, N.; Smith, D.; York, R.

    2001-01-01

    identification of the radioactive material. Specialised equipment is required for performing one or more of the steps indicated above, which can be divided into three categories: Pocket type instruments, used to detect the presence of radioactive materials and to inform the investigator about the radiation level; hand-held and mobile instruments, required to detect, locate or identify radioactive materials; and fixed installed, automatic instruments, designed to be located stationary at road and rail border crossings, airports, seaports, etc. Detailed recommendations for technical specifications and operation of this equipment have been derived. A particular problem is the definition of an 'investigation level', at which an alarm is triggered and consequent investigation of individuals, vehicles or goods should be established. This level has to be sufficiently high to avoid frequent false alarms, however, also sufficiently low to detect significant radiation sources or nuclear materials, even if they are inside shielded containers and possibly buried in metal scrap. 'Response' covers all necessary actions required after radioactive materials have been detected. Detailed recommendations have been derived for the procedures of operational response by the first responder, as well as for tactical response, when a serious radiological situation develops or detection of nuclear materials requires outside expert assistance. Operational response, after activation of a detection alarm, initiates with the assessment of radiation hazard, verification measurements that the alarm is genuine and subsequent localisation of the radioactive material. If the radiological hazard is not to be considered very significant, i.e. if the dose rate is below O.I mSv/h at a distance of one meter from the item containing the source, no indication of neutron radiation is present and no suspicion of contamination exists, the first responder may continue to identify the radioactive material and determine, if

  8. Modeling the mechanical and aging properties of silicone rubber and foam - stockpile-historical & additively manufactured materials

    Energy Technology Data Exchange (ETDEWEB)

    Maiti, A; Weisgraber, T H; Gee, R H

    2014-09-30

    M97* and M9763 belong to the M97xx series of cellular silicone materials that have been deployed as stress cushions in some of the LLNL systems. Their purpose of these support foams is to distribute the stress between adjacent components, maintain relative positioning of various components, and mitigate the effects of component size variation due to manufacturing and temperature changes. In service these materials are subjected to a continuous compressive strain over long periods of time. In order to ensure their effectiveness, it is important to understand how their mechanical properties change over time. The properties we are primarily concerned about are: compression set, load retention, and stress-strain response (modulus).

  9. Dual stimuli responsive self-reporting material for chemical reservoir coating

    Science.gov (United States)

    Lee, Tae Hee; Song, Young Kyu; Park, Sun Hee; Park, Young Il; Noh, Seung Man; Kim, Jin Chul

    2018-03-01

    In this study, we introduce a novel dual stimuli responsive self-reporting thiol-epoxy thermoset (DSRTET) coatings which can detect both crack occurrence and pH variation. For crack detection, microcapsule containing tetraphenylethylene (TPE) which exhibits aggregation induced emission (AIE) effect was prepared via multi-step emulsion polymerization and dispersed in DSRTET coatings. For pH variation detection, commercial thymol blue as a pH indicator was added into the polymer matrix. The effect of microcapsule contents in DSRTET on their curing behavior, material properties, and crack sensitivity was characterized using an oscillatory rheology, rigid body pendulum test (RPT), nano-indentation test (NST), universal test machine (UTM) and scratch tester. It was revealed that crack sensitivity of DSRTET coatings was greatly influenced by material properties as well as microcapsule content. The color transition of DSRTET coatings in response to acid or base solution were quantitatively investigated using a multi-angle spectrophotometer after simple acid and base solution drop tests. The color of DSRTET coatings changed from a pale green to red for acidic solution and to blue for basic solution. Finally, The DSRTET used in this study was applied to laboratory scale chemical reservoirs in order to verify the potential as a dual stimuli response self-reporting coating which can detect both crack in coating material and chemical spill caused by the leakage or breakage of the reservoir part.

  10. Determination of the stress-strain curve in specimens of Scots pine for numerical simulation of defect free beams

    Directory of Open Access Journals (Sweden)

    Baño, V.

    2012-06-01

    Full Text Available The objective of this paper is to develop a twodimensional numerical model to simulate the response of Scots pine (Pinus sylvestris L. defect free timber members in order to predict the behaviour of these members when subjected to external forces. For this purpose, data of the mechanical properties of Scots pine were obtained by performing experimental tests on specimens. We determined the stresses and deformations of timber beams in the elastic-plastic and plastic phases. In addition, we developed a finite element software that considered the orthotropic nature of timber, the non-linearity of the compression-reduction branch and the differing moduli of elasticity in tension and compression for Scots pine beams free from defects. The software developed simulates an experimental four point bending test according to UNE-EN 408 Standard.

    El objetivo de este trabajo es el desarrollo de un modelo numérico bidimensional de piezas de madera de Pinus sylvestris L. libre de defectos que prediga su comportamiento frente a solicitaciones externas. Para su desarrollo, fue necesario realizar ensayos experimentales sobre probetas de pequeño tamaño con el fin de obtener los datos de las propiedades mecánicas para el Pinus sylvestris L. de procedencia española. A partir de los datos experimentales obtenidos, se desarrolla un programa de elementos finitos que considera la ortotropía de la madera, la no linealidad de la rama compresión-acortamiento y los distintos módulos de elasticidad a tracción y a compresión para vigas libres de defectos. El programa simula el ensayo experimental de flexión en cuatro puntos según la Norma UNE-EN 408 y aborda la determinación de las tensiones y deformaciones de las vigas de madera en las tres fases de comportamiento: elástica, elastoplástica y plástica.

  11. Combined Characterization of the Time Response of Impression Materials via Traditional and FTIR Measurements

    Directory of Open Access Journals (Sweden)

    Giacomo Derchi

    2015-05-01

    Full Text Available We investigated the temporal response of four dental impression materials, namely three siloxanes (Imprint 4, Flexitime, Aquasil and one polyether (Impregum. The null hypothesis was that the nominal working times are confirmed by instrumental laboratory tests. We also aimed to identify alternative techniques with strong physical-chemical background for the assessment of temporal response. Traditional characterization was carried out by shark fin test device and durometer at both ambient and body temperature. Additionally, Fourier-transform infrared spectroscopy was performed at room temperature. From shark fin height and Shore hardness versus time the working time and the setting time of the materials were evaluated, respectively. These were in reasonable agreement with the nominal values, except for Impregum, which showed longer working time. Spectroscopy confirmed the different character of the two types of materials, and provided for Imprint 4 and Aquasil an independent evaluation of both evolution times, consistent with the results of the other techniques. Shark fin test and durometer measurements showed deviations in setting time, low sensitivity to temperature for Flexitime, and longer working time at higher temperature for Impregum. Deviations of working time appear in operating conditions from what specified by the manufacturers. Fourier-transform infrared spectroscopy can provide insight in the correlation between material properties and their composition and structure.

  12. Thermo-visco-plasticity and creep in structural-material response of folded-plate structures

    Directory of Open Access Journals (Sweden)

    Milašinović Dragan D.

    2017-01-01

    Full Text Available Many structural parts are exposed to high temperatures and loading. It is then important to have data about material inelastic behaviour under such exploiting conditions. Influence of temperature on mechanical characteristics of a material may be inserted via the creep coefficient in the range of visco-elasto-plastic (VEP strains. This damage parameter is implemented in this paper in conjunction with mathematical material modelling approach named rheological-dynamical analogy (RDA in order to address structural stiffness reduction due to inelastic material behaviour. The aim of this paper is to define structural-material internal damping based on both the RDA dynamic modulus and modal damping ratio, by modelling critically damped dynamic systems in the steady-state response. These systems are credible base for explanation of the phenomenon of thermo-visco-plasticity and creep in structural-material response due to high temperatures and loading. Though elastic buckling information for folded-plate structures is not a direct predictor of capacity or collapse behaviour on its own, both the mode and the load (moment are important proxies for the actual behaviour. In current design codes, such as AISI S100, New Zealand/Australia, and European Union, the design formulae are calibrated through the calculation of elastic critical buckling loads (or moments to predict the ultimate strength, thus the ability to calculate the associated elastic buckling loads (or moments has great importance. Moreover, the buckling mode shapes are commonly employed into non-linear collapse modelling as initial geometric imperfections and thermal performance of folded-plate structures in fire. To examine the buckling behaviour of folded-plate structures, the main numerical solution methods are used such as the finite element method (FEM and finite strip method (FSM. This paper aims at providing a unified frame for quasi-static inelastic buckling and thermal loading of

  13. Functional design criteria for the Hazardous Materials Management and Emergency Response (HAMMER) Training Center. Revision 1

    International Nuclear Information System (INIS)

    Sato, P.K.

    1995-01-01

    Within the United States, there are few hands-on training centers capable of providing integrated technical training within a practical application environment. Currently, there are no training facilities that offer both radioactive and chemical hazardous response training. There are no hands-on training centers that provide training for both hazardous material operations and emergency response that also operate as a partnership between organized labor, state agencies, tribes, and local emergency responders within the US Department of Energy (DOE) complex. Available facilities appear grossly inadequate for training the thousands of people at Hanford, and throughout the Pacific Northwest, who are required to qualify under nationally-mandated requirements. It is estimated that 4,000 workers at the Hanford Site alone need hands-on training. Throughout the Pacific Northwest, the potential target audience would be over 30,000 public sector emergency response personnel, as well as another 10,000 clean-up workers represented by organized labor. The HAMMER Training Center will be an interagency-sponsored training center. It will be designed, built, and operated to ensure that clean-up workers, fire fighters, and public sector management and emergency response personnel are trained to handle accidental spills of hazardous materials. Training will cover wastes at clean-up sites, and in jurisdictions along the transportation corridors, to effectively protect human life, property, and the environment

  14. Ultrafast terahertz-induced response of GeSbTe phase-change materials

    Energy Technology Data Exchange (ETDEWEB)

    Shu, Michael J. [Department of Applied Physics, Stanford University, Stanford, California 94305 (United States); Stanford Institute for Materials and Energy Sciences, SLAC National Accelerator Laboratory, Menlo Park, California 94025 (United States); Zalden, Peter [Stanford Institute for Materials and Energy Sciences, SLAC National Accelerator Laboratory, Menlo Park, California 94025 (United States); PULSE Institute, SLAC National Accelerator Laboratory, Menlo Park, California 94025 (United States); Chen, Frank [Stanford Institute for Materials and Energy Sciences, SLAC National Accelerator Laboratory, Menlo Park, California 94025 (United States); Department of Electrical Engineering, Stanford University, Stanford, California 94305 (United States); Weems, Ben [Department of Materials Science and Engineering, Stanford University, Stanford, California 94305 (United States); Chatzakis, Ioannis [Stanford Institute for Materials and Energy Sciences, SLAC National Accelerator Laboratory, Menlo Park, California 94025 (United States); Xiong, Feng; Jeyasingh, Rakesh; Pop, Eric; Philip Wong, H.-S. [Department of Electrical Engineering, Stanford University, Stanford, California 94305 (United States); Hoffmann, Matthias C. [SLAC National Accelerator Laboratory, Menlo Park, California 94025 (United States); Wuttig, Matthias [I. Physikalisches Institut, RWTH Aachen University, 52056 Aachen (Germany); JARA–Fundamentals of Information Technology, RWTH Aachen University, 52056 Aachen (Germany); Lindenberg, Aaron M., E-mail: aaronl@stanford.edu [Stanford Institute for Materials and Energy Sciences, SLAC National Accelerator Laboratory, Menlo Park, California 94025 (United States); PULSE Institute, SLAC National Accelerator Laboratory, Menlo Park, California 94025 (United States); Department of Materials Science and Engineering, Stanford University, Stanford, California 94305 (United States)

    2014-06-23

    The time-resolved ultrafast electric field-driven response of crystalline and amorphous GeSbTe films has been measured all-optically, pumping with single-cycle terahertz pulses as a means of biasing phase-change materials on a sub-picosecond time-scale. Utilizing the near-band-gap transmission as a probe of the electronic and structural response below the switching threshold, we observe a field-induced heating of the carrier system and resolve the picosecond-time-scale energy relaxation processes and their dependence on the sample annealing condition in the crystalline phase. In the amorphous phase, an instantaneous electroabsorption response is observed, quadratic in the terahertz field, followed by field-driven lattice heating, with Ohmic behavior up to 200 kV/cm.

  15. Time history nonlinear earthquake response analysis considering materials and geometrical nonlinearity

    International Nuclear Information System (INIS)

    Kobayashi, T.; Yoshikawa, K.; Takaoka, E.; Nakazawa, M.; Shikama, Y.

    2002-01-01

    A time history nonlinear earthquake response analysis method was proposed and applied to earthquake response prediction analysis for a Large Scale Seismic Test (LSST) Program in Hualien, Taiwan, in which a 1/4 scale model of a nuclear reactor containment structure was constructed on sandy gravel layer. In the analysis both of strain-dependent material nonlinearity, and geometrical nonlinearity by base mat uplift, were considered. The 'Lattice Model' for the soil-structure interaction model was employed. An earthquake record on soil surface at the site was used as control motion, and deconvoluted to the input motion of the analysis model at GL-52 m with 300 Gal of maximum acceleration. The following two analyses were considered: (A) time history nonlinear, (B) equivalent linear, and the advantage of time history nonlinear earthquake response analysis method is discussed

  16. Over-the-road tests of nuclear materials package response to normal environments

    International Nuclear Information System (INIS)

    Gwinn, K.W.; Glass, R.E.; Edwards, K.R.

    1991-12-01

    In support of the development of American National Standards Institute standards for the transport of radioactive materials, Sandia has a program to characterize the normal transport environment. This program includes both analytical modeling of package and trailer responses, and over-the-road tests to measure those responses. This paper presents the results of a series of over-the-road tests performed using Chem-Nuclear equipment in the Barnwell, SC, area. The test events included a variety of road types such as rough concrete, shock events such as railroad grade crossings, and driver responses such as sharp turns. The response of the package and trailer to these events was measured with accelerometers at various locations to determine the inertial loads. Either load cells or strain gages were used to measure tiedown response. These accelerations and loads were measured on systems with flexible and ''rigid'' tiedowns. The results indicated that while significant accelerations occur on the trailer bed, these do not translate into equivalent loads in either the package or the tiedown system. This indicates that trailer-bed response should not be used in determining the load factor for fatigue calculations of the package components or in determining design loads for tiedowns

  17. Identification of material properties of orthotropic composite plate using experimental frequency response function data

    Science.gov (United States)

    Tam, Jun Hui; Ong, Zhi Chao; Ismail, Zubaidah; Ang, Bee Chin; Khoo, Shin Yee

    2018-05-01

    The demand for composite materials is increasing due to their great superiority in material properties, e.g., lightweight, high strength and high corrosion resistance. As a result, the invention of composite materials of diverse properties is becoming prevalent, and thus, leading to the development of material identification methods for composite materials. Conventional identification methods are destructive, time-consuming and costly. Therefore, an accurate identification approach is proposed to circumvent these drawbacks, involving the use of Frequency Response Function (FRF) error function defined by the correlation discrepancy between experimental and Finite-Element generated FRFs. A square E-glass epoxy composite plate is investigated under several different configurations of boundary conditions. It is notable that the experimental FRFs are used as the correlation reference, such that, during computation, the predicted FRFs are continuously updated with reference to the experimental FRFs until achieving a solution. The final identified elastic properties, namely in-plane elastic moduli, Ex and Ey, in-plane shear modulus, Gxy, and major Poisson's ratio, vxy of the composite plate are subsequently compared to the benchmark parameters as well as with those obtained using modal-based approach. As compared to the modal-based approach, the proposed method is found to have yielded relatively better results. This can be explained by the direct employment of raw data in the proposed method that avoids errors that might incur during the stage of modal extraction.

  18. Effect of environmental and material factors on the response of nanocomposite foam impact sensors

    Science.gov (United States)

    Bird, Evan; Merrell, Jake; Rosquist, Parker; Martineau, Adin; Bowden, Anton; Seeley, Matthew; Fullwood, David

    2018-05-01

    Nanocomposite foam (NCF) is a multifunctional material that can be used to measure impact. Interactions between the flexible polymer matrix and conductive particles dispersed throughout it produce a voltage signal under dynamic strain, which correlates to the magnitude of impact. Though promising in applications requiring both impact sensing and energy absorption, NCF’s voltage response has been observed to suffer from significant signal drift. This paper investigates several causes of variance in the response of NCF sensors to consistent impacts. These effects can be classified into three general types: recoverable transient effects (such as those relating to viscoelasticity or capacitive charging), environmental drift (due to humidity and temperature), and permanent signal decay from material degradation. The motivation for the study arises from various potential repeat-impact applications where periodic recalibration of the sensor would be difficult (such as a gait-tracking insole in use for a marathon event). A cyclic drop testing machine was used to apply consistent impacts to NCF, and drift resulting from each factor (in ranges typical of an insole environment) was experimentally isolated. Models representing each factor’s contribution to signal drift are presented. Of the factors investigated, humidity and temperature caused the most significant drift, with permanent material degradation accounting for only minor decay in voltage response. Transient effects were also observed, with a characteristic ‘warm-up’ (or ‘charging’) time required for the NCF to achieve steady-state; this phenomenon, and the related ‘recovery’ time for the material to return to its original state, were determined. The resultant data can be leveraged to implement a correction algorithm or other drift-compensating method to retain an NCF sensor’s accuracy in both long and short data collection scenarios.

  19. A New Material Constitutive Model for Predicting Cladding Failure

    Energy Technology Data Exchange (ETDEWEB)

    Rashid, Joe; Dunham, Robert [ANATECH Corp., San Diego, CA (United States); Rashid, Mark [University of California Davis, Davis, CA (United States); Machiels, Albert [EPRI, Palo Alto, CA (United States)

    2009-06-15

    An important issue in fuel performance and safety evaluations is the characterization of the effects of hydrides on cladding mechanical response and failure behavior. The hydride structure formed during power operation transforms the cladding into a complex multi-material composite, with through-thickness concentration profile that causes cladding ductility to vary by more than an order of magnitude between ID and OD. However, current practice of mechanical property testing treats the cladding as a homogeneous material characterized by a single stress-strain curve, regardless of its hydride morphology. Consequently, as irradiation conditions and hydrides evolution change, new material property testing is required, which results in a state of continuous need for valid material property data. A recently developed constitutive model, treats the cladding as a multi-material composite in which the metal and the hydride platelets are treated as separate material phases with their own elastic-plastic and fracture properties and interacting at their interfaces with appropriate constraint conditions between them to ensure strain and stress compatibility. An essential feature of the model is a multi-phase damage formulation that models the complex interaction between the hydride phases and the metal matrix and the coupled effect of radial and circumferential hydrides on cladding stress-strain response. This gives the model the capability of directly predicting cladding failure progression during the loading event and, as such, provides a unique tool for constructing failure criteria analytically where none could be developed by conventional material testing. Implementation of the model in a fuel behavior code provides the capability to predict in-reactor operational failures due to PCI or missing pellet surfaces (MPS) without having to rely on failure criteria. Even, a stronger motivation for use of the model is in the transportation accidents analysis of spent fuel

  20. A numerical study of stress/strain response to oil development in reservoir rocks-a case study in Xingshugang area of Daqing Anticline

    International Nuclear Information System (INIS)

    Li Zian; Ma Teng; Yi Jin; Zhu Jiangjian; Lin Ge; Zhang Lu; Zhu Yan; Sun Yaliang; Zhu Jun

    2010-01-01

    Formation pressure and the underground stress field will be disturbed by high pressure injection and production activities during oilfield development. Such disturbance will induce the deformation of formation rock, sometimes causing formation to slip. As a result, production wells and/or injection wells will encounter sanding, casing deformation, or even casing shear problems. This article introduced a simulation study on formation pressure and the underground stress field variation during injection and production activities in the Xingshugang area of the Daqing Anticline, Songliao Basin, China. The relationships of injection pressure to formation pressure, underground stress field variation, and strain variation were investigated in this paper.

  1. Development of a Multi-Scale Methodology for Prediction of the Microscopic Anisotropic Stress-Strain Response of Textured Metals under Dynamic Loading

    Science.gov (United States)

    2009-01-21

    will be denoted by v ⊗ u. Superscript T indicates the transpose operation (AT )ij = Aji for any second-order tensor A while symbol ‘tr‘ denotes the...indicated in red . which was subsequently marked on the plate as shown in Figure 2. Note that the plate exhibits fiber texture resulting from the...specimen deformed to 10% strain reveals that many grains have twinned (twins appear red in Figure 9). The twin volume fraction was estimated to be 17

  2. Materialism.

    Science.gov (United States)

    Melnyk, Andrew

    2012-05-01

    Materialism is nearly universally assumed by cognitive scientists. Intuitively, materialism says that a person's mental states are nothing over and above his or her material states, while dualism denies this. Philosophers have introduced concepts (e.g., realization and supervenience) to assist in formulating the theses of materialism and dualism with more precision, and distinguished among importantly different versions of each view (e.g., eliminative materialism, substance dualism, and emergentism). They have also clarified the logic of arguments that use empirical findings to support materialism. Finally, they have devised various objections to materialism, objections that therefore serve also as arguments for dualism. These objections typically center around two features of mental states that materialism has had trouble in accommodating. The first feature is intentionality, the property of representing, or being about, objects, properties, and states of affairs external to the mental states. The second feature is phenomenal consciousness, the property possessed by many mental states of there being something it is like for the subject of the mental state to be in that mental state. WIREs Cogn Sci 2012, 3:281-292. doi: 10.1002/wcs.1174 For further resources related to this article, please visit the WIREs website. Copyright © 2012 John Wiley & Sons, Ltd.

  3. Cell response of calcium phosphate based ceramics, a bone substitute material

    Directory of Open Access Journals (Sweden)

    Juliana Marchi

    2013-01-01

    Full Text Available The aim of this study was to characterize calcium phosphate ceramics with different Ca/P ratios and evaluate cell response of these materials for use as a bone substitute. Bioceramics consisting of mixtures of hydroxyapatite (HAp and β-tricalcium phosphate (β-TCP powders in different proportions were pressed and sintered. The physical and chemical properties of these bioceramics were then characterized. Characterization of the biological properties of these materials was based on analysis of cell response using cultured fibroblasts. The number of cells attached to the samples was counted from SEM images of samples exposed to cell culture solution for different periods. These data were compared by analysis of variance (ANOVA complemented by the Tukey's test. The TCP sample had higher surface roughness and lower density. The adherence and growth of FMM1 cells on samples from all groups was studied. Even though the different calcium based ceramics exhibited properties which made them suitable as bone substitutes, those with higher levels of β-TCP revealed improved cell growth on their surfaces. These observations indicated two-phase calcium phosphate based materials with a β-TCP surface layer to be a promising bone substitute.

  4. Emergency response network design for hazardous materials transportation with uncertain demand

    Directory of Open Access Journals (Sweden)

    Kamran Shahanaghi

    2012-10-01

    Full Text Available Transportation of hazardous materials play an essential role on keeping a friendly environment. Every day, a substantial amount of hazardous materials (hazmats, such as flammable liquids and poisonous gases, need to be transferred prior to consumption or disposal. Such transportation may result in unsuitable events for people and environment. Emergency response network is designed for this reason where specialist responding teams resolve any issue as quickly as possible. This study proposes a new multi-objective model to locate emergency response centers for transporting the hazardous materials. Since many real-world applications are faced with uncertainty in input parameters, the proposed model of this paper also assumes that reference and demand to such centre is subject to uncertainty, where demand is fuzzy random. The resulted problem formulation is modelled as nonlinear non-convex mixed integer programming and we used NSGAII method to solve the resulted problem. The performance of the proposed model is examined with several examples using various probability distribution and they are compared with the performance of other existing method.

  5. Testing and modeling the dynamic response of foam materials for blast protection

    Science.gov (United States)

    Fitek, John H.

    The pressure wave released from an explosion can cause injury to the lungs. A personal armor system concept for blast lung injury protection consists of a polymer foam layer behind a rigid armor plate to be worn over the chest. This research develops a method for testing and modeling the dynamic response of foam materials to be used for down-selection of materials for this application. Constitutive equations for foam materials are incorporated into a lumped parameter model of the combined armor plate and foam system. Impact testing and shock tube testing are used to measure the foam model parameters and validate the model response to a pressure wave load. The plate and foam armor model is then coupled to a model of the human thorax. With a blast pressure wave input, the armor model is evaluated based on how it affects the injury-causing mechanism of chest wall motion. Results show that to reduce chest wall motion, the foam must compress at a relatively constant stress level, which requires a sufficient foam thickness.

  6. Experimental studies of dynamic impact response with scale models of lead shielded radioactive material shipping containers

    International Nuclear Information System (INIS)

    Robinson, R.A.; Hadden, J.A.; Basham, S.J.

    1978-01-01

    Preliminary experimental studies of dynamic impact response of scale models of lead-shielded radioactive material shipping containers are presented. The objective of these studies is to provide DOE/ECT with a data base to allow the prediction of a rational margin of confidence in overviewing and assessing the adequacy of the safety and environmental control provided by these shipping containers. Replica scale modeling techniques were employed to predict full scale response with 1/8, 1/4, and 1/2 scale models of shipping containers that are used in the shipment of spent nuclear fuel and high level wastes. Free fall impact experiments are described for scale models of plain cylindrical stainless steel shells, stainless steel shells filled with lead, and replica scale models of radioactive material shipping containers. Dynamic induced strain and acceleration measurements were obtained at several critical locations on the models. The models were dropped from various heights, attitudes to the impact surface, with and without impact limiters and at uniform temperatures between -40 and 175 0 C. In addition, thermal expansion and thermal gradient induced strains were measured at -40 and 175 0 C. The frequency content of the strain signals and the effect of different drop pad compositions and stiffness were examined. Appropriate scale modeling laws were developed and scaling techniques were substantiated for predicting full scale response by comparison of dynamic strain data for 1/8, 1/4, and 1/2 scale models with stainless steel shells and lead shielding

  7. WE-FG-207B-02: Material Reconstruction for Spectral Computed Tomography with Detector Response Function

    International Nuclear Information System (INIS)

    Liu, J; Gao, H

    2016-01-01

    Purpose: Different from the conventional computed tomography (CT), spectral CT based on energy-resolved photon-counting detectors is able to provide the unprecedented material composition. However, an important missing piece for accurate spectral CT is to incorporate the detector response function (DRF), which is distorted by factors such as pulse pileup and charge-sharing. In this work, we propose material reconstruction methods for spectral CT with DRF. Methods: The polyenergetic X-ray forward model takes the DRF into account for accurate material reconstruction. Two image reconstruction methods are proposed: a direct method based on the nonlinear data fidelity from DRF-based forward model; a linear-data-fidelity based method that relies on the spectral rebinning so that the corresponding DRF matrix is invertible. Then the image reconstruction problem is regularized with the isotropic TV term and solved by alternating direction method of multipliers. Results: The simulation results suggest that the proposed methods provided more accurate material compositions than the standard method without DRF. Moreover, the proposed method with linear data fidelity had improved reconstruction quality from the proposed method with nonlinear data fidelity. Conclusion: We have proposed material reconstruction methods for spectral CT with DRF, whichprovided more accurate material compositions than the standard methods without DRF. Moreover, the proposed method with linear data fidelity had improved reconstruction quality from the proposed method with nonlinear data fidelity. Jiulong Liu and Hao Gao were partially supported by the NSFC (#11405105), the 973 Program (#2015CB856000), and the Shanghai Pujiang Talent Program (#14PJ1404500).

  8. From biowaste to magnet-responsive materials for water remediation from polycyclic aromatic hydrocarbons.

    Science.gov (United States)

    Nisticò, Roberto; Cesano, Federico; Franzoso, Flavia; Magnacca, Giuliana; Scarano, Domenica; Funes, Israel G; Carlos, Luciano; Parolo, Maria E

    2018-07-01

    Composted urban biowaste-derived substances (BBS-GC) are used as carbon sources for the preparation of carbon-coated magnet-sensitive nanoparticles obtained via co-precipitation method and the subsequent thermal treatment at 550 °C under nitrogen atmosphere. A multitechnique approach has been applied to investigate the morphology, magnetic properties, phase composition, thermal stability of the obtained magnet-sensitive materials. In particular, pyrolysis-induced modifications affecting the BBS-GC/carbon shell were highlighted. The adsorption capacity of such bio-derivative magnetic materials for the removal of hydrophobic contaminants such as polycyclic aromatic hydrocarbons was evaluated in order to verify their potential application in wastewater remediation process. The promising results suggest their use as a new generation of magnet-responsive easily-recoverable adsorbents for water purification treatments. Copyright © 2018 Elsevier Ltd. All rights reserved.

  9. Analysis of material response to ultrasonic vibration loading in turning Inconel 718

    International Nuclear Information System (INIS)

    Ahmed, N.; Mitrofanov, A.V.; Babitsky, V.I.; Silberschmidt, V.V.

    2006-01-01

    The paper is focused on the analysis of the surface layer formed on a workpiece treated with ultrasonically assisted turning (UAT) in comparison to conventional turning (CT). Various experimental methods are used to study the difference between the two machining techniques: nanoindentation, light microscopy and scanning electron microscopy (SEM). The experimental part of the paper studies the material response to CT and UAT in terms of material's hardness, residual stresses, and changes in the microstructure. The difference in the distribution of residual stresses in the machined surface layer is further studied by means of numerical (finite element) simulations. A three-dimensional thermomechanically coupled finite element (FE) model of both UAT and CT is used to study temperature distributions in the process zone and thermally induced stresses. Numerical results are compared with the obtained experimental data

  10. Project management plan, Hazardous Materials Management and Emergency Response Training Center

    International Nuclear Information System (INIS)

    Borgeson, M.E.

    1994-01-01

    For the next 30 years, the main activities at the Hanford Site will involve the handling and cleanup of toxic substances. Thousands of workers involved in these new activities will need systematic training appropriate to their tasks and associated risks. This project is an important part of the Hanford Site mission and will enable the US Department of Energy (DOE) to meet high standards for safety. The Hazardous Materials Management and Emergency Response Training Center (HAMMER) project will construct a centralized regional training center dedicated to training hazardous materials workers and emergency responders in classrooms and with hands-on, realistic training aids representing actual field conditions. The HAMMER Training Center will provide a cost-effective, high-quality way to meet the Hanford Site training needs. The training center creates a partnership among DOE; government contractors; labor; local, state, and tribal governments; and selected institutions of higher education

  11. Core-Shell Structured Electro- and Magneto-Responsive Materials: Fabrication and Characteristics

    Directory of Open Access Journals (Sweden)

    Hyoung Jin Choi

    2014-11-01

    Full Text Available Core-shell structured electrorheological (ER and magnetorheological (MR particles have attracted increasing interest owing to their outstanding field-responsive properties, including morphology, chemical and dispersion stability, and rheological characteristics of shear stress and yield stress. This study covers recent progress in the preparation of core-shell structured materials as well as their critical characteristics and advantages. Broad emphasises from the synthetic strategy of various core-shell particles to their feature behaviours in the magnetic and electric fields have been elaborated.

  12. Visible-Light Modulation on Lattice Dielectric Responses of a Piezo-Phototronic Soft Material.

    Science.gov (United States)

    Huang, E-Wen; Hsu, Yu-Hsiang; Chuang, Wei-Tsung; Ko, Wen-Ching; Chang, Chung-Kai; Lee, Chih-Kung; Chang, Wen-Chi; Liao, Tzu-Kang; Thong, Hao Cheng

    2015-12-16

    In situ synchrotron X-ray diffraction is used to investigate a three-way piezo-phototronic soft material. This new system is composed of a semi-crystalline poly(vinylidene fluoride-co-trifluoroethylene) piezoelectric polymer and titanium oxide nanoparticles. Under light illumination, photon-induced piezoelectric responses are nearly two times higher at both the lattice-structure and the macroscopic level than under conditions without light illumination. A mechanistic model is proposed. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  13. Project T100 -- Hazardous Materials Management and Emergency Response Training Center (HAMMER)

    International Nuclear Information System (INIS)

    Norton, C.E.

    1994-01-01

    The scope of this Quality Assurance Program Plan (QAPP) is to provide a system of Quality Assurance reviews and verifications on the design and construction of the Hazardous Materials Management and Emergency Response (HAMMER) Training Center, project 95L-EWT-100 at Hanford. The reviews and verifications will be on activities associated with design, procurement, and construction of the HAMMER project which includes, but is not limited to earthwork, placement of concrete, laying of rail, drilling of wells, water and sewer line fabrication and installation, communications systems, fire protection/detection systems, line tie-ins, building and mock-up (prop) construction, electrical, instrumentation, pump and valves and special coatings

  14. Assessing mesoscale material response under shock & isentropic compression via high-resolution line-imaging VISAR.

    Energy Technology Data Exchange (ETDEWEB)

    Hall, Clint Allen; Furnish, Michael David; Podsednik, Jason W.; Reinhart, William Dodd; Trott, Wayne Merle; Mason, Joshua

    2003-10-01

    Of special promise for providing dynamic mesoscale response data is the line-imaging VISAR, an instrument for providing spatially resolved velocity histories in dynamic experiments. We have prepared two line-imaging VISAR systems capable of spatial resolution in the 10-20 micron range, at the Z and STAR facilities. We have applied this instrument to selected experiments on a compressed gas gun, chosen to provide initial data for several problems of interest, including: (1) pore-collapse in copper (two variations: 70 micron diameter hole in single-crystal copper) and (2) response of a welded joint in dissimilar materials (Ta, Nb) to ramp loading relative to that of a compression joint. The instrument is capable of resolving details such as the volume and collapse history of a collapsing isolated pore.

  15. Development of a virtual reality training system. An application to emergency response in radioactive materials transport

    International Nuclear Information System (INIS)

    Watabe, Naohito

    2003-01-01

    A virtual reality (VR) training system was developed for the purpose of confirming the applicability of virtual reality on training systems for emergency response of radioactive materials transport. This system has following features; 1) Accident scenarios were derived from an event tree analysis. 2) Instructors can edit the training scenario. 3) Three VR scenes were prepared: vehicle and equipment checks, vehicle travel on an expressway, and emergency response in a tunnel fire accident. 4) every action by users is recorded automatically. 5) Instructors and users hold briefing session after the training, and they can review and confirm the results with VR animation. 6) A support database is provided for the convenience of users. The applicability of the system was validated through some trial applications and demonstrations. (author)

  16. Nonlocality and particle-clustering effects on the optical response of composite materials with metallic nanoparticles

    Science.gov (United States)

    Chen, C. W.; Chung, H. Y.; Chiang, H.-P.; Lu, J. Y.; Chang, R.; Tsai, D. P.; Leung, P. T.

    2010-10-01

    The optical properties of composites with metallic nanoparticles are studied, taking into account the effects due to the nonlocal dielectric response of the metal and the coalescing of the particles to form clusters. An approach based on various effective medium theories is followed, and the modeling results are compared with those from the cases with local response and particles randomly distributed through the host medium. Possible observations of our modeling results are illustrated via a calculation of the transmission of light through a thin film made of these materials. It is found that the nonlocal effects are particularly significant when the particles coalesce, leading to blue-shifted resonances and slightly lower values in the dielectric functions. The dependence of these effects on the volume fraction and fractal dimension of the metal clusters is studied in detail.

  17. Multiferroic and magnetoelectric materials – Developments and perspectives

    Directory of Open Access Journals (Sweden)

    Shvartsman V. V.

    2012-06-01

    Full Text Available Multiferroic (MF materials with simultaneous magnetic and electric long range order and occasionally, mutual magnetoelectric (ME coupling, have recently attracted considerable interest. The small linear ME effect has been shown to control spintronic devices very efficiently, e.g. via the classic ME antiferromagnet Cr2O3 using exchange bias. Similar nano-engineering concepts exist also for type-I MF single phase materials, whose magnetic and polar orders have distinct origins like BiFeO3. Strong ME coupling occurs in type-II multiferroics, where ferroelectricity is due to spiral spin order as in TbMnO3. Record high ME response coming close to applicability arises in stress-strain coupled multiphase magnetoelectrics such as PZT/FeBSiC composites. Higher order ME response in disordered systems (“type-III multiferroics” extends the conventional MF scenario toward ME quantum paraelectric and multiglass materials with polarization-induced control of magnetic exchange, as e.g. in EuTiO3, Sr0.98Mn0.02TiO3, and PbFe0.5Nb0.5O3.

  18. Hazardous materials emergency response training program at Texas A ampersand M University

    International Nuclear Information System (INIS)

    Stirling, A.G.

    1989-01-01

    The Texas Engineering Extension Service (TEEX) as the engineering vocational training arm of the Texas A ampersand M University system has conducted oil-spill, hazardous-material, and related safety training for industry since 1976 and fire suppression training since 1931. In 1987 TEEX conducted training for some 66,000 persons, of which some 6000 were in hazardous-materials safety training and 22,000 in fire suppression or related fields. Various laws and regulations exist relative to employee training at an industrial facility, such as the Hazard Communication Act, the Resource Conservation and Recovery Act (RCRA), the Comprehensive Environmental Response, Compensation, and Liability Act (CERCLA or more commonly Superfund), the Community Right to Know Law, and the Superfund Amendments and Reauthorization Act (SARA), Titles I and III. The TEEX programs developed on the foundation emphasize the hands-on approach (60% field exercises) to provide a comprehensive training curriculum resulting in regulatory compliance, an effective emergency response capability, a prepared community, and a safe work environment

  19. Experimental and Analytical Characterization of the Macromechanical Response for Triaxial Braided Composite Materials

    Science.gov (United States)

    Littell, Justin D.

    2013-01-01

    micromacromechanical computer model is created to simulate the behavior of these composite material systems under static and ballistic impact loading using the test data acquired. The model also quantifies the way in which the fiber/matrix interface affects material response under static and impact loading. The results show that the test methods are capable of accurately quantifying the polymer resin under a variety of strain rates and temperature for three loading conditions. The resin strength and stiffness data show a clear rate and temperature dependence. The data also show the hydrostatic stress effects and hysteresis, all of which can be used by researchers developing composite constitutive models for the resins. The results for the composite data reveal noticeable differences in strength, failure strain, and stiffness in the different material systems presented. The investigations into the microscale failure mechanisms provide information about the nature of the different material system behaviors. Finally, the developed computer model predicts composite static strength and stiffness to within 10 percent of the gathered test data and also agrees with composite impact data, where available.

  20. Materials

    CSIR Research Space (South Africa)

    Van Wyk, Llewellyn V

    2009-02-01

    Full Text Available . It is generally included as part of a structurally insulated panel (SIP) where the foam is sandwiched between external skins of steel, wood or cement. Cement composites Cement bonded composites are an important class of building materials. These products... for their stone buildings, including the Egyptians, Aztecs and Inca’s. As stone is a very dense material it requires intensive heating to become warm. Rocks were generally stacked dry but mud, and later cement, can be used as a mortar to hold the rocks...

  1. Geometrical Feature Extraction from Ultrasonic Time Frequency Responses: An Application to Nondestructive Testing of Materials

    Directory of Open Access Journals (Sweden)

    Naranjo Valery

    2010-01-01

    Full Text Available Signal processing is an essential tool in nondestructive material characterization. Pulse-echo inspection with ultrasonic energy provides signals (A-scans that can be processed in order to obtain parameters which are related to physical properties of inspected materials. Conventional techniques are based on the use of a short-term frequency analysis of the A-scan, obtaining a time-frequency response (TFR, to isolate the evolution of the different frequency-dependent parameters. The application of geometrical estimators to TFRs provides an innovative way to complement conventional techniques based on the one-dimensional evolution of an A-scan extracted parameter (central or centroid frequency, bandwidth, etc.. This technique also provides an alternative method of obtaining similar meaning and less variance estimators. A comparative study of conventional versus new proposed techniques is presented in this paper. The comparative study shows that working with binarized TFRs and the use of shape descriptors provide estimates with lower bias and variance than conventional techniques. Real scattering materials, with different scatterer sizes, have been measured in order to demonstrate the usefulness of the proposed estimators to distinguish among scattering soft tissues. Superior results, using the proposed estimators in real measures, were obtained when classifying according to mean scatterer size.

  2. Advanced composites structural concepts and materials technologies for primary aircraft structures: Structural response and failure analysis

    Science.gov (United States)

    Dorris, William J.; Hairr, John W.; Huang, Jui-Tien; Ingram, J. Edward; Shah, Bharat M.

    1992-01-01

    Non-linear analysis methods were adapted and incorporated in a finite element based DIAL code. These methods are necessary to evaluate the global response of a stiffened structure under combined in-plane and out-of-plane loading. These methods include the Arc Length method and target point analysis procedure. A new interface material model was implemented that can model elastic-plastic behavior of the bond adhesive. Direct application of this method is in skin/stiffener interface failure assessment. Addition of the AML (angle minus longitudinal or load) failure procedure and Hasin's failure criteria provides added capability in the failure predictions. Interactive Stiffened Panel Analysis modules were developed as interactive pre-and post-processors. Each module provides the means of performing self-initiated finite elements based analysis of primary structures such as a flat or curved stiffened panel; a corrugated flat sandwich panel; and a curved geodesic fuselage panel. This module brings finite element analysis into the design of composite structures without the requirement for the user to know much about the techniques and procedures needed to actually perform a finite element analysis from scratch. An interactive finite element code was developed to predict bolted joint strength considering material and geometrical non-linearity. The developed method conducts an ultimate strength failure analysis using a set of material degradation models.

  3. Instruction in the responsible conduct of research: an inventory of programs and materials within CTSAs.

    Science.gov (United States)

    DuBois, James M; Schilling, Debie A; Heitman, Elizabeth; Steneck, Nicholas H; Kon, Alexander A

    2010-06-01

    The National Institutes of Health (NIH) require instruction in the responsible conduct of research (RCR) as a component of any Clinical and Translational Science Award (CTSA). The Educational Materials Group of the NIH CTSA Consortium's Clinical Research Ethics Key Function Committee (CRE-KFC) conducted a survey of the 38 institutions that held CTSA funding as of January 2009 to determine how they satisfy RCR training requirements. An 8-item questionnaire was sent by email to directors of the Clinical Research Ethics, the Educational and Career Development, and the Regulatory Knowledge cores. We received 78 completed surveys from 38 CTSAs (100%). We found that there is no unified approach to RCR training across CTSAs, many programs lack a coherent plan for RCR instruction, and most CTSAs have not developed unique instructional materials tailored to the needs of clinical and translational scientists. We recommend collaboration among CTSAs and across CTSA key function committees to address these weaknesses. We also requested that institutions send electronic copies of original RCR training materials to share among CTSAs via the CTSpedia website. Twenty institutions submitted at least one educational product. The CTSpedia now contains more than 90 RCR resources.

  4. Investigation of Effects of Material Architecture on the Elastic Response of a Woven Ceramic Matrix Composite

    Science.gov (United States)

    Goldberg, Robert K.; Bonacuse, Peter J.; Mital, Subodh K.

    2012-01-01

    To develop methods for quantifying the effects of the microstructural variations of woven ceramic matrix composites on the effective properties and response of the material, a research program has been undertaken which is described in this paper. In order to characterize and quantify the variations in the microstructure of a five harness satin weave, CVI SiC/SiC, composite material, specimens were serially sectioned and polished to capture images that detailed the fiber tows, matrix, and porosity. Open source quantitative image analysis tools were then used to isolate the constituents and collect relevant statistics such as within ply tow spacing. This information was then used to build two dimensional finite element models that approximated the observed section geometry. With the aid of geometrical models generated by the microstructural characterization process, finite element models were generated and analyses were performed to quantify the effects of the microstructure and its variation on the effective stiffness and areas of stress concentration of the material. The results indicated that the geometry and distribution of the porosity appear to have significant effects on the through-thickness modulus. Similarly, stress concentrations on the outer surface of the composite appear to correlate to regions where the transverse tows are separated by a critical amount.

  5. Dynamic response of materials on subnanosecond time scales, and beryllium properties for inertial confinement fusion

    International Nuclear Information System (INIS)

    Swift, Damian C.; Tierney, Thomas E.; Luo Shengnian; Paisley, Dennis L.; Kyrala, George A.; Hauer, Allan; Greenfield, Scott R.; Koskelo, Aaron C.; McClellan, Kenneth J.; Lorenzana, Hector E.; Kalantar, Daniel; Remington, Bruce A.; Peralta, Pedro; Loomis, Eric

    2005-01-01

    During the past few years, substantial progress has been made in developing experimental techniques capable of investigating the response of materials to dynamic loading on nanosecond time scales and shorter, with multiple diagnostics probing different aspects of the behavior. These relatively short time scales are scientifically interesting because plastic flow and phase changes in common materials with simple crystal structures--such as iron--may be suppressed, allowing unusual states to be induced and the dynamics of plasticity and polymorphism to be explored. Loading by laser-induced ablation can be particularly convenient: this technique has been used to impart shocks and isentropic compression waves from ∼1 to 200 GPa in a range of elements and alloys, with diagnostics including line imaging surface velocimetry, surface displacement (framed area imaging), x-ray diffraction (single crystal and polycrystal), ellipsometry, and Raman spectroscopy. A major motivation has been the study of the properties of beryllium under conditions relevant to the fuel capsule in inertial confinement fusion: magnetically driven shock and isentropic compression shots at Z were used to investigate the equation of state and shock melting characteristics, complemented by laser ablation experiments to investigate plasticity and heterogeneous response from the polycrystalline microstructure. These results will help to constrain acceptable tolerances on manufacturing, and possible loading paths, for inertial fusion ignition experiments at the National Ignition Facility. Laser-based techniques are being developed further for future material dynamics experiments, where it should be possible to obtain high quality data on strength and phase changes up to at least 1 TPa

  6. The effect of loading time on flexible pavement dynamic response: a finite element analysis

    Science.gov (United States)

    Yin, Hao; Solaimanian, Mansour; Kumar, Tanmay; Stoffels, Shelley

    2007-12-01

    Dynamic response of asphalt concrete (AC) pavements under moving load is a key component for accurate prediction of flexible pavement performance. The time and temperature dependency of AC materials calls for utilizing advanced material characterization and mechanistic theories, such as viscoelasticity and stress/strain analysis. In layered elastic analysis, as implemented in the new Mechanistic-Empirical Pavement Design Guide (MEPDG), the time dependency is accounted for by calculating the loading times at different AC layer depths. In this study, the time effect on pavement response was evaluated by means of the concept of “pseudo temperature.” With the pavement temperature measured from instrumented thermocouples, the time and temperature dependency of AC materials was integrated into one single factor, termed “effective temperature.” Via this effective temperature, pavement responses under a transient load were predicted through finite element analysis. In the finite element model, viscoelastic behavior of AC materials was characterized through relaxation moduli, while the layers with unbound granular material were assumed to be in an elastic mode. The analysis was conducted for two different AC mixtures in a simplified flexible pavement structure at two different seasons. Finite element analysis results reveal that the loading time has a more pronounced impact on pavement response in the summer for both asphalt types. The results indicate that for reasonable prediction of dynamic response in flexible pavements, the effect of the depth-dependent loading time on pavement temperature should be considered.

  7. Radiation response of industrial materials: Dose-rate and morphology implications

    International Nuclear Information System (INIS)

    Berejka, Anthony J.

    2007-01-01

    Industrial uses of ionizing radiation mostly rely upon high current, high dose-rate (100 kGy/s) electron beam (EB) accelerators. To a lesser extent, industry uses low dose-rate (2.8 x 10 -3 kGy/s) radioactive Cobalt-60 as a gamma source, generally for some rather specific purposes, as medical device sterilization and the treatment of food and foodstuffs. There are nearly nine times as many (∼1400) high current EB units in commercial operation than gamma sources (∼160). However, gamma sources can be easily scaled-down so that much research on materials effects is conducted using gamma radiation. Likewise, laboratories are more likely to have very low beam current and consequently low dose-rate accelerators such as Van de Graaff generators and linear accelerators. With the advent of very high current EB accelerators, X-ray processing has become an industrially viable option. With X-rays from high power sources, dose-rates can be modulated based upon accelerator power and the attenuation of the X-ray by the distance of the material from the X-ray target. Dose and dose-rate dependence has been found to be of consequence in several commercial applications which can employ the use of ionizing radiation. The combination of dose and dose-rate dependence of the polymerization and crosslinking of wood impregnants and of fiber composite matrix materials can yield more economically viable results which have promising commercial potential. Monomer and oligomer structure also play an important role in attaining these desirable results. The influence of morphology is shown on the radiation response of olefin polymers, such as ethylene, propylene and isobutylene polymers and their copolymers. Both controlled morphology and controlled dose-rate have commercial consequences. These are also impacted both by the adroit selection of materials and through the possible use of X-ray processing

  8. Equivalence between short-time biphasic and incompressible elastic material responses.

    Science.gov (United States)

    Ateshian, Gerard A; Ellis, Benjamin J; Weiss, Jeffrey A

    2007-06-01

    Porous-permeable tissues have often been modeled using porous media theories such as the biphasic theory. This study examines the equivalence of the short-time biphasic and incompressible elastic responses for arbitrary deformations and constitutive relations from first principles. This equivalence is illustrated in problems of unconfined compression of a disk, and of articular contact under finite deformation, using two different constitutive relations for the solid matrix of cartilage, one of which accounts for the large disparity observed between the tensile and compressive moduli in this tissue. Demonstrating this equivalence under general conditions provides a rationale for using available finite element codes for incompressible elastic materials as a practical substitute for biphasic analyses, so long as only the short-time biphasic response is sought. In practice, an incompressible elastic analysis is representative of a biphasic analysis over the short-term response deltatelasticity tensor, and K is the hydraulic permeability tensor of the solid matrix. Certain notes of caution are provided with regard to implementation issues, particularly when finite element formulations of incompressible elasticity employ an uncoupled strain energy function consisting of additive deviatoric and volumetric components.

  9. SB certification handout material requirements, test methods, responsibilities, and minimum classification levels for mixture-based specification for flexible base.

    Science.gov (United States)

    2012-10-01

    A handout with tables representing the material requirements, test methods, responsibilities, and minimum classification levels mixture-based specification for flexible base and details on aggregate and test methods employed, along with agency and co...

  10. Identifying factors related to Achilles tendon stress, strain, and stiffness before and after 6 months of growth in youth 10-14 years of age.

    Science.gov (United States)

    Neugebauer, Jennifer M; Hawkins, David A

    2012-09-21

    The purposes of this study were (1) determine if youth peak Achilles tendon (AT) strain, peak AT stress, and AT stiffness, measured during an isometric plantar flexion, differed after six months (mos) of growth, and (2) determine if sex, physical activity level (Physical Activity Questionnaire (PAQ-C)), and/or growth rate (GR) were related to these properties. AT stress, strain, and stiffness were quantified in 20 boys (13.47±0.81 years) and 22 girls (11.18±0.82 years) at 2 times (0 and 6 mos). GR (change in height in 6 mos) was not significantly different between boys and girls (3.5±1.4 and 3.4±1.1cm/6 mos respectively). Peak AT strain and stiffness (mean 3.8±0.4% and 128.9±153.6N/mm, respectively) did not differ between testing sessions or sex. Peak AT stress (22.1±2.4 and 24.0±2.1MPa at 0 and 6 mos, respectively) did not differ between sex and increased significantly at 6 mos due to a significant decrease in AT cross-sectional area (40.6±1.3 and 38.1±1.6mm(2) at 0 and 6 mos, respectively) with no significant difference in peak AT force (882.3±93.9 and 900.3± 65.5N at 0 and 6 mos, respectively). Peak AT stress was significantly greater in subjects with greater PAQ-C scores (9.1% increase with 1 unit increase in PAQ-C score) and smaller in subjects with faster GRs (13.8% decrease with 1cm/6 mos increase in GR). These results indicate that of the AT mechanical properties quantified, none differed between sex, and only peak AT stress significantly differed after 6 months and was related to GR and physical activity. Copyright © 2012 Elsevier Ltd. All rights reserved.

  11. Factors affecting seismic response of submarine slopes

    Directory of Open Access Journals (Sweden)

    G. Biscontin

    2006-01-01

    Full Text Available The response of submerged slopes on the continental shelf to seismic or storm loading has become an important element in the risk assessment for offshore structures and 'local' tsunami hazards worldwide. The geological profile of these slopes typically includes normally consolidated to lightly overconsolidated soft cohesive soils with layer thickness ranging from a few meters to hundreds of meters. The factor of safety obtained from pseudo-static analyses is not always a useful measure for evaluating the slope response, since values less than one do not necessarily imply slope failure with large movements of the soil mass. This paper addresses the relative importance of different factors affecting the response of submerged slopes during seismic loading. The analyses use a dynamic finite element code which includes a constitutive law describing the anisotropic stress-strain-strength behavior of normally consolidated to lightly overconsolidated clays. The model also incorporates anisotropic hardening to describe the effect of different shear strain and stress histories as well as bounding surface principles to provide realistic descriptions of the accumulation of the plastic strains and excess pore pressure during successive loading cycles. The paper presents results from parametric site response analyses on slope geometry and layering, soil material parameters, and input ground motion characteristics. The predicted maximum shear strains, permanent deformations, displacement time histories and maximum excess pore pressure development provide insight of slope performance during a seismic event.

  12. Mechanics of materials formulas and problems : engineering mechanics 2

    CERN Document Server

    Gross, Dietmar; Wriggers, Peter; Schröder, Jörg; Müller, Ralf

    2017-01-01

    This book contains the most important formulas and more than 140 completely solved problems from Mechanics of Materials and Hydrostatics. It provides engineering students material to improve their skills and helps to gain experience in solving engineering problems. Particular emphasis is placed on finding the solution path and formulating the basic equations. Topics include: - Stress - Strain - Hooke’s Law - Tension and Compression in Bars - Bending of Beams - Torsion - Energy Methods - Buckling of Bars - Hydrostatics .

  13. Mechanical compatibility and stress analyses in composite materials

    International Nuclear Information System (INIS)

    Schimmoeller, H.; Ruge, J.

    1976-01-01

    This paper gives a short description of the problem of mechanical interactions and mechanical compatibility in composite bodies. The formation of stress-strain states, caused by the mechanical compatibility by bonding of the interfaces, is discussed. The difference between the continuous and discontinuous type of material transition in the interface is described. Flat laminated materials are at first considered. For this type of composite bodies thermal stresses and thermal residual stresses are elastically-plastically calculated. (orig.) [de

  14. Glass interface effect on high-strain-rate tensile response of a soft polyurethane elastomeric polymer material

    NARCIS (Netherlands)

    Fan, J.T.; Weerheijm, J.; Sluys, L.J.

    2015-01-01

    The glass interface effect on dynamic tensile response of a soft polyurethane elastomeric polymer material has been investigated by subjecting a glass-polymer system of this polymer material matrix embedded a single 3 mm-diameter glass particle to impact loading in a split Hopkinson tension bar

  15. Testing Plastic Deformations of Materials in the Introductory Undergraduate Mechanics Laboratory

    Science.gov (United States)

    Romo-Kroger, C. M.

    2012-01-01

    Normally, a mechanics laboratory at the undergraduate level includes an experiment to verify compliance with Hooke's law in materials, such as a steel spring and an elastic rubber band. Stress-strain curves are found for these elements. Compression in elastic bands is practically impossible to achieve due to flaccidity. A typical experiment for…

  16. On the effects of geometry, defects, and material asymmetry on the mechanical response of shape memory alloy cellular lattice structures

    International Nuclear Information System (INIS)

    Ravari, M R Karamooz; Kadkhodaei, M; Ghaei, A; Esfahani, S Nasr; Andani, M Taheri; Elahinia, M; Karaca, H

    2016-01-01

    Shape memory alloy (such as NiTi) cellular lattice structures are a new class of advanced materials with many potential applications. The cost of fabrication of these structures however is high. It is therefore necessary to develop modeling methods to predict the functional behavior of these alloys before fabrication. The main aim of the present study is to assess the effects of geometry, microstructural imperfections and material asymmetric response of dense shape memory alloys on the mechanical response of cellular structures. To this end, several cellular and dense NiTi samples are fabricated using a selective laser melting process. Both cellular and dense specimens were tested in compression in order to obtain their stress–strain response. For modeling purposes, a three -dimensional (3D) constitutive model based on microplane theory which is able to describe the material asymmetry was employed. Five finite element models based on unit cell and multi-cell methods were generated to predict the mechanical response of cellular lattices. The results show the considerable effects of the microstructural imperfections on the mechanical response of the cellular lattice structures. The asymmetric material response of the bulk material also affects the mechanical response of the corresponding cellular structure. (paper)

  17. Novel Method to Characterize and Model the Multiaxial Constitutive and Damage Response of Energetic Materials.

    Energy Technology Data Exchange (ETDEWEB)

    Kaneshige, Michael J. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Rabbi, Md Fazle [Univ. of Texas, El Paso, TX (United States); Kaneshige, Michael J. [Univ. of Texas, El Paso, TX (United States); Mach, Robert [Univ. of Texas, El Paso, TX (United States); Catzin, Carlos A. [Univ. of Texas, El Paso, TX (United States); Stewart, Calvin M. [Univ. of Texas, El Paso, TX (United States)

    2017-12-01

    Simulant polymer bonded explosives are widely used to simulate the mechanical response of real energetic materials. In this paper, the fracture resistance of a simulant polymer bo nded explosive (PBX) is experimentally investigated. The simulant is composed of 80 wt.% soda lime glass beads (SLGB) and 20 wt.% high impact Polystyrene 825 (HIPS). Brazilian disk tests are performed to characterize the tensile and compressive properties. Fracture toughness and energy tests are performed in the semi - circular bending (SCB) configuration on 80, 81, 82, and 83 wt % SLGB compositions. Digital image correlation is performed to record the surface displacements and calculate surface strains during testing. The m icromechanical behavior of ductile and brittle fracture are evaluated using digital microscopy and scanning electron microscopy of the fracture surface. It is determined that (i) the manufacturing process produces a credible simulant of PBX properties, and (ii) the SCB test measures fracture resistance with a reasonable coefficient of variation.

  18. Simulating Ice Shelf Response to Potential Triggers of Collapse Using the Material Point Method

    Science.gov (United States)

    Huth, A.; Smith, B. E.

    2017-12-01

    Weakening or collapse of an ice shelf can reduce the buttressing effect of the shelf on its upstream tributaries, resulting in sea level rise as the flux of grounded ice into the ocean increases. Here we aim to improve sea level rise projections by developing a prognostic 2D plan-view model that simulates the response of an ice sheet/ice shelf system to potential triggers of ice shelf weakening or collapse, such as calving events, thinning, and meltwater ponding. We present initial results for Larsen C. Changes in local ice shelf stresses can affect flow throughout the entire domain, so we place emphasis on calibrating our model to high-resolution data and precisely evolving fracture-weakening and ice geometry throughout the simulations. We primarily derive our initial ice geometry from CryoSat-2 data, and initialize the model by conducting a dual inversion for the ice viscosity parameter and basal friction coefficient that minimizes mismatch between modeled velocities and velocities derived from Landsat data. During simulations, we implement damage mechanics to represent fracture-weakening, and track ice thickness evolution, grounding line position, and ice front position. Since these processes are poorly represented by the Finite Element Method (FEM) due to mesh resolution issues and numerical diffusion, we instead implement the Material Point Method (MPM) for our simulations. In MPM, the ice domain is discretized into a finite set of Lagrangian material points that carry all variables and are tracked throughout the simulation. Each time step, information from the material points is projected to a Eulerian grid where the momentum balance equation (shallow shelf approximation) is solved similarly to FEM, but essentially treating the material points as integration points. The grid solution is then used to determine the new positions of the material points and update variables such as thickness and damage in a diffusion-free Lagrangian frame. The grid does not store

  19. Effect of bimodularity on frequency response of cylindrical panels ...

    Indian Academy of Sciences (India)

    M. Senthilkumar (Newgen Imaging) 1461 1996 Oct 15 13:05:22

    The actual stress strain behaviour ... The work on frequency response of bimodular structures is scarce in open literature (Khan .... Analysis is carried out using a C0 eight-noded serendipity quadrilateral shear flexible shell ..... specified convergence tolerance (each incremental displacement becomes less than equal to. 10.

  20. Histological evaluations and inflammatory responses of different dental implant abutment materials: A human histology pilot study.

    Science.gov (United States)

    Sampatanukul, Teeratida; Serichetaphongse, Pravej; Pimkhaokham, Atiphan

    2018-04-01

    Improvements of soft tissue to the abutment surface results in more stable peri-implant conditions, however, few human histological studies have compared soft tissue responses around different abutment materials. To describe the peri-implant tissue around 3 abutment materials; titanium, zirconia, and gold alloy, over an 8-week healing period. Fifteen edentulous sites were treated with implants. Eight weeks later, peri-implant tissue was harvested and processed using a nonseparation resin embedded technique. The tissue attachment characteristics were assessed at clinical stages using the gingival index (GI) score, surgical stage (surgical score), and histological stage (histological attachment percentage). Additionally, the inflammatory responses were evaluated using inflammatory extent and inflammatory cellularity grades. Nonparametrical statistics were used to describe the GI and surgical scores, and analytical statistics were used to analyze the histological attachment percentages as well as the inflammatory extent and cellularity grades amongst the 3 groups. There were no statistically significant differences among the groups for GI score (P = .071) and surgical score (P = .262). Titanium and zirconia exhibited nearly similar mean histological attachment percentages while gold alloy had a significantly lower percentage (P = .004). For the inflammatory extent and cellularity grades, the odds of being one grade higher for gold alloy abutment was 5.18 and 17.8 times that of titanium abutment, respectively. However, for the zirconia abutment, the odds were 0.87 and 7.5 times higher than the titanium group. The tissue around the gold alloy abutments resulted in worse attachment conditions compared with the titanium and zirconia abutments. Inflammation tended to be higher in the tissue around the gold alloy abutments than the titanium and zirconia abutments. © 2017 Wiley Periodicals, Inc.

  1. Cytogenetic Dosimetry: Applications in Preparedness for and Response to Radiation Emergencies - Training Materials

    International Nuclear Information System (INIS)

    2013-01-01

    These materials are designed for use at a four day training course on the application of cytogenetic dosimetry in preparedness for and response to radiation emergencies. They contain information on: (1) Basics of biological effects of ionizing radiation: Parts 1+2; (2) Basics of dosimetry; (3) dicentric assay; (4) Retrospective dosimetry by translocation analysis; (5) Premature chromosome condensation analysis; (6) Cytokinesis block micronucleus assay; (7) Applied statistics for biodosimetry; (8) Automatic analysis of chromosomal assays; (9) Biodosimetry in mass casualty events; (10) Safety of laboratory staff and quality programmes; (11) Examples of accident investigations; (12) Cytogenetic dose estimation in the criticality accident in Tokaimura; (13) Radiological accidents in Latin America; (14) Radiological accidents in Georgia. Additionally, the CD contains two working sessions with the reference materials for use and a standard training programme. This training course consists of lectures and work sessions that can easily be utilized by a State to build a basic capability in biodosimetry application in a nuclear or radiological emergency

  2. Materials and noncoplanar mesh designs for integrated circuits with linear elastic responses to extreme mechanical deformations.

    Science.gov (United States)

    Kim, Dae-Hyeong; Song, Jizhou; Choi, Won Mook; Kim, Hoon-Sik; Kim, Rak-Hwan; Liu, Zhuangjian; Huang, Yonggang Y; Hwang, Keh-Chih; Zhang, Yong-wei; Rogers, John A

    2008-12-02

    Electronic systems that offer elastic mechanical responses to high-strain deformations are of growing interest because of their ability to enable new biomedical devices and other applications whose requirements are impossible to satisfy with conventional wafer-based technologies or even with those that offer simple bendability. This article introduces materials and mechanical design strategies for classes of electronic circuits that offer extremely high stretchability, enabling them to accommodate even demanding configurations such as corkscrew twists with tight pitch (e.g., 90 degrees in approximately 1 cm) and linear stretching to "rubber-band" levels of strain (e.g., up to approximately 140%). The use of single crystalline silicon nanomaterials for the semiconductor provides performance in stretchable complementary metal-oxide-semiconductor (CMOS) integrated circuits approaching that of conventional devices with comparable feature sizes formed on silicon wafers. Comprehensive theoretical studies of the mechanics reveal the way in which the structural designs enable these extreme mechanical properties without fracturing the intrinsically brittle active materials or even inducing significant changes in their electrical properties. The results, as demonstrated through electrical measurements of arrays of transistors, CMOS inverters, ring oscillators, and differential amplifiers, suggest a valuable route to high-performance stretchable electronics.

  3. CERN antiproton target: Hydrocode analysis of its core material dynamic response under proton beam impact

    Directory of Open Access Journals (Sweden)

    Claudio Torregrosa Martin

    2016-07-01

    Full Text Available Antiprotons are produced at CERN by colliding a 26  GeV/c proton beam with a fixed target made of a 3 mm diameter, 55 mm length iridium core. The inherent characteristics of antiproton production involve extremely high energy depositions inside the target when impacted by each primary proton beam, making it one of the most dynamically demanding among high energy solid targets in the world, with a rise temperature above 2000 °C after each pulse impact and successive dynamic pressure waves of the order of GPa’s. An optimized redesign of the current target is foreseen for the next 20 years of operation. As a first step in the design procedure, this numerical study delves into the fundamental phenomena present in the target material core under proton pulse impact and subsequent pressure wave propagation by the use of hydrocodes. Three major phenomena have been identified, (i the dominance of a high frequency radial wave which produces destructive compressive-to-tensile pressure response (ii The existence of end-of-pulse tensile waves and its relevance on the overall response (iii A reduction of 44% in tensile pressure could be obtained by the use of a high density tantalum cladding.

  4. Basalt fiber reinforced porous aggregates-geopolymer based cellular material

    Science.gov (United States)

    Luo, Xin; Xu, Jin-Yu; Li, Weimin

    2015-09-01

    Basalt fiber reinforced porous aggregates-geopolymer based cellular material (BFRPGCM) was prepared. The stress-strain curve has been worked out. The ideal energy-absorbing efficiency has been analyzed and the application prospect has been explored. The results show the following: fiber reinforced cellular material has successively sized pore structures; the stress-strain curve has two stages: elastic stage and yielding plateau stage; the greatest value of the ideal energy-absorbing efficiency of BFRPGCM is 89.11%, which suggests BFRPGCM has excellent energy-absorbing property. Thus, it can be seen that BFRPGCM is easy and simple to make, has high plasticity, low density and excellent energy-absorbing features. So, BFRPGCM is a promising energy-absorbing material used especially in civil defense engineering.

  5. Magnetomechanical local-global effects in magnetostrictive composite materials

    Science.gov (United States)

    Elhajjar, Rani F.; Law, Chiu T.

    2015-10-01

    A constitutive model for magnetostrictive composite materials (MCMs) that describes the relations among stress, strain, magnetic field, and magnetization Liu and Zheng (2005 Acta Mech. Sin. 21 278-85) is implemented for multiphysics simulation for analysis of non-periodic or non-uniform microstructure effects. The multiphysics models that capture designed and actual microstructural details are used for predicting the responses of magnetostrictive composite materials under various mechanical and magnetic loading conditions. The approach overcomes the limitation with strain gages in the investigation of magnetostrictive strain due to stress localization around magnetostrictive phases. Three-dimensional digital image correlation (3D-DIC) is used to measure the displacements and strain in the composites under fluctuating magnetic fields. The specimens are prepared using epoxy and particulate magnetostrictive materials with the particles in the range of approximately 20 to 300 microns range. We examine the displacement and strain fields obtained and compare the results to those obtained from fiber Bragg grating (FBG) measurements. The coupling coefficients obtained from this method were in agreement with those measured using other techniques. The validated model allows us to predict the effect of curing, preload, microstructure alignment and particle shape on the magnetostrictive strains.

  6. Magnetomechanical local-global effects in magnetostrictive composite materials

    International Nuclear Information System (INIS)

    Elhajjar, Rani F; Law, Chiu T

    2015-01-01

    A constitutive model for magnetostrictive composite materials (MCMs) that describes the relations among stress, strain, magnetic field, and magnetization Liu and Zheng (2005 Acta Mech. Sin. 21 278–85) is implemented for multiphysics simulation for analysis of non-periodic or non-uniform microstructure effects. The multiphysics models that capture designed and actual microstructural details are used for predicting the responses of magnetostrictive composite materials under various mechanical and magnetic loading conditions. The approach overcomes the limitation with strain gages in the investigation of magnetostrictive strain due to stress localization around magnetostrictive phases. Three-dimensional digital image correlation (3D-DIC) is used to measure the displacements and strain in the composites under fluctuating magnetic fields. The specimens are prepared using epoxy and particulate magnetostrictive materials with the particles in the range of approximately 20 to 300 microns range. We examine the displacement and strain fields obtained and compare the results to those obtained from fiber Bragg grating (FBG) measurements. The coupling coefficients obtained from this method were in agreement with those measured using other techniques. The validated model allows us to predict the effect of curing, preload, microstructure alignment and particle shape on the magnetostrictive strains. (paper)

  7. Stochastic isotropic hyperelastic materials: constitutive calibration and model selection

    Science.gov (United States)

    Mihai, L. Angela; Woolley, Thomas E.; Goriely, Alain

    2018-03-01

    Biological and synthetic materials often exhibit intrinsic variability in their elastic responses under large strains, owing to microstructural inhomogeneity or when elastic data are extracted from viscoelastic mechanical tests. For these materials, although hyperelastic models calibrated to mean data are useful, stochastic representations accounting also for data dispersion carry extra information about the variability of material properties found in practical applications. We combine finite elasticity and information theories to construct homogeneous isotropic hyperelastic models with random field parameters calibrated to discrete mean values and standard deviations of either the stress-strain function or the nonlinear shear modulus, which is a function of the deformation, estimated from experimental tests. These quantities can take on different values, corresponding to possible outcomes of the experiments. As multiple models can be derived that adequately represent the observed phenomena, we apply Occam's razor by providing an explicit criterion for model selection based on Bayesian statistics. We then employ this criterion to select a model among competing models calibrated to experimental data for rubber and brain tissue under single or multiaxial loads.

  8. 陷落柱填隙物全应力-应变过程的渗流特性研究%Research on permeability characteristics of karst collapse column fillings in complete stress-strain process

    Institute of Scientific and Technical Information of China (English)

    张勃阳; 白海波; 张凯

    2016-01-01

    岩溶陷落柱易导通含水层与煤层从而引发底板突水事故,已经成为我国华北地区下组煤开采的重要安全隐患。对于固结良好的陷落柱,其填隙物的渗透性直接影响着陷落柱的整体渗透性,且在采动压力的影响下,陷落柱填隙物的渗透性也在不断发生变化。为研究不同应力状态下填隙物渗透率的变化规律,对填隙物进行固结重塑,并利用MTS815.02渗流试验系统对重塑后不同初始含水率的填隙物试样进行了不同围压条件下的全应力-应变过程的渗流特性试验。试验结果表明:1)陷落柱填隙物全应力-应变过程渗透率的变化曲线可划分为压密段、破坏段和蠕变段,渗透率对应的呈现出减小-增大-减小的变化规律;2)填隙物的全应力-应变过程的渗透率峰值随围压的增大而减小,其峰值比与围压差存在指数函数关系;3)填隙物的初始渗透率和孔隙度随初始含水率的增大而增大,渗透率比和孔隙度比存在幂函数关系,在全应力-应变过程中渗透率峰值与初始值的差随初始含水率的增大而减小。%The floor water-inrush accident caused by karst collapse column is easy to break over the aquifer and coal seam. This kind of accident has become the serious danger of lower group coal mining in northern China. For the well-consolidated collapse column, the permeability of the fillings directly affects that of the overall collapse column, and the permeability of fillings constantly changes under the influence of mining. The study on seepage characteristic of collapse column fillings is conducted with MTS815.02 seepage test system in a complete stress-strain process and the variation of permeability under different strain states. Meanwhile the influence of initial moisture content and confining pressure on the fillings permeability is analyzed in this test. The results show that: 1) The representative stress-strain

  9. Development of computational dynamic properties analysis method and optimum design method of tissue construction under consideration of microstructure of materials for nuclear power

    International Nuclear Information System (INIS)

    Shiraishi, Haruki; Tabuchi, Masaaki; Nakasone, Yuji

    1999-01-01

    A practical reactor core material produces particles by irradiation in the matrix. The second phase particle lattice was defined and the effects of its basic parameters on the stress-strain curve were evaluated. As the basic parameters, 0.01 to 0.95 μm of particle diameter, 1.0μm of grain spacing and 0.3 of work-hardening exponent were used. The effect of the particle diameter on the stress-strain curve was studied by the large deformation finite element method. The concentration area of distortion was produced from the back of the second phase particles, and its process specified the sharp of stress-strain curve. The calculation method did not assume breaking of particles and separation of the interface of particle and matrix. So that, the values obtained showed the upper limits of strength, ductility and fracture toughness of the composite materials. (S.Y.)

  10. Calcium Phosphate as a Key Material for Socially Responsible Tissue Engineering

    Directory of Open Access Journals (Sweden)

    Vuk Uskoković

    2016-06-01

    Full Text Available Socially responsible technologies are designed while taking into consideration the socioeconomic, geopolitical and environmental limitations of regions in which they will be implemented. In the medical context, this involves making therapeutic platforms more accessible and affordable to patients in poor regions of the world wherein a given disease is endemic. This often necessitates going against the reigning trend of making therapeutic nanoparticles ever more structurally complex and expensive. However, studies aimed at simplifying materials and formulations while maintaining the functionality and therapeutic response of their more complex counterparts seldom provoke a significant interest in the scientific community. In this review we demonstrate that such compositional simplifications are meaningful when it comes to the design of a solution for osteomyelitis, a disease that is in its natural, non-postoperative form particularly prevalent in the underdeveloped parts of the world wherein poverty, poor sanitary conditions, and chronically compromised defense lines of the immune system are the norm. We show that calcium phosphate nanoparticles, which are inexpensive to make, could be chemically designed to possess the same functionality as a hypothetic mixture additionally composed of: (a a bone growth factor; (b an antibiotic for prophylactic or anti-infective purposes; (c a bisphosphonate as an antiresorptive compound; (d a viral vector to enable the intracellular delivery of therapeutics; (e a luminescent dye; (f a radiographic component; (g an imaging contrast agent; (h a magnetic domain; and (i polymers as viscous components enabling the injectability of the material and acting as carriers for the sustained release of a drug. In particular, calcium phosphates could: (a produce tunable drug release profiles; (b take the form of viscous and injectable, self-setting pastes; (c be naturally osteo-inductive and inhibitory for osteoclastogenesis

  11. Pengembangan tes kemampuan literasi sains pada materi momentum dan impuls dengan Analisis Item Response Theory (IRT

    Directory of Open Access Journals (Sweden)

    Della Apriyani Kusuma Putri

    2018-04-01

    Full Text Available Kemampuan literasi sains adalah suatu kemampuan yang memungkinkan seseorang untuk membuat suatu keputusan dengan pengetahuan konsep dan proses sains yang dimilikinya. Berbagai macam permasalahan yang terjadi di era globalisasi ini menuntut siswa untuk tidak hanya cakap dalam aspek kognitif tapi juga mampu memberi keputusan untuk memecahkan permasalahan, sehingga dapat dikatakan bahwa kemampuan literasi sains adalah kemampuan yang penting dan harus dimiliki siswa. Oleh karena itu, dibutuhkan instrumen untuk mengukur kemampuan literasi sains. hal inilah yang mendasari peneliti mengembangkan instrumen kemampuan literasi sains. Tujuan penelitian ini adalah untuk mengembangkan dan mengetahui karakteristik tes kemampuan literasi sains fisika siswa SMA pada materi momentum dan impuls berdasarkan aspek literasi sains yang dikemukakan oleh Gormally. Metode penelitian yang diterapkan adalah penelitian dan pengembangan (Research and Development yaitu metode penelitian yang digunakan untuk menghasilkan produk tertentu, dan menguji keefektifan produk tersebut. Sebelum diuji coba tes telah divalidasi oleh tiga orang validator dan menghasilkan kesimpulan bahwa tes cukup baik dan dapat diuji coba. Hasil analisis menggunakan Item Response Theory menunjukkan bahwa model 3PL adalah model yang sesuai dengan karakteristik tes. Sedangkan karakteristik tes yang meliputi daya pembeda, tingkat kesukaran, dan faktor tebakan termasuk dalam kategori baik. Science literacy skills is an ability that allows one to make a decision with the knowledge of the concepts and processes of science has. A wide variety of problems that occur in a globalized world requires students to not only proficient in cognitive but also able to make a decision to solve the problem, so it can be said that the ability of science literacy is an important capability and must be owned by the students. Therefore, the instrument is required to measure the ability of science literacy. This problem is

  12. Meso-scale modelling of the heat conductivity effect on the shock response of a porous material

    Science.gov (United States)

    Resnyansky, A. D.

    2017-06-01

    Understanding of deformation mechanisms of porous materials under shock compression is important for tailoring material properties at the shock manufacturing of advanced materials from substrate powders and for studying the response of porous materials under shock loading. Numerical set-up of the present work considers a set of solid particles separated by air representing a volume of porous material. Condensed material in the meso-scale set-up is simulated with a viscoelastic rate sensitive material model with heat conduction formulated from the principles of irreversible thermodynamics. The model is implemented in the CTH shock physics code. The meso-scale CTH simulation of the shock loading of the representative volume reveals the mechanism of pore collapse and shows in detail the transition from a high porosity case typical for abnormal Hugoniot response to a moderate porosity case typical for conventional Hugoniot response. Results of the analysis agree with previous analytical considerations and support hypotheses used in the two-phase approach.

  13. IFE chamber dry wall materials response to pulsed X-rays and ions at power-plant level fluences

    Energy Technology Data Exchange (ETDEWEB)

    Renk, T.J. E-mail: tjrenk@sandia.gov; Olson, C.L.; Tanaka, T.J.; Ulrickson, M.A.; Rochau, G.A.; Peterson, R.R.; Golovkin, I.E.; Thompson, M.O.; Knowles, T.R.; Raffray, A.R.; Tillack, M.S

    2003-04-01

    We have begun a collaborative investigation of the response of candidate first-wall inertial fusion energy (IFE) reactor chamber drywall materials to X-rays on the Z facility, and to ions on RHEPP-1, both located at Sandia National Laboratories. Dose levels are comparable to those anticipated in future direct-drive reactors. Due to the 5-10 Hz repetition rate expected in such reactors, per-pulse effects such as material removal must be negligible. The primary wall materials investigated here are graphite and tungsten in various forms. After exposure on either RHEPP or Z, materials were analyzed for roughening and/or material removal (ablation) as a function of dose. Graphite is observed to undergo significant ablation/sublimation in response to ion exposure at the 3-4 J/cm{sup 2} level, significantly below doses expected in future dry-wall power plants. Evidence of thermomechanical stresses resulting in material loss occurs for both graphite and tungsten, and is probably related to the pulsed nature of the energy delivery. These effects are not seen in typical magnetic fusion energy (MFE) conditions where these same kinds of materials are used. Results are presented for thresholds below which no roughening or ablation occurs. Use of graphite in a 'velvet' two-dimensional form may mitigate the effects seen with the flat material, and alloying tungsten with rhenium may reduce its roughening due to the increased ductility of the alloy.

  14. Picosecond laser ablation of poly-L-lactide: Effect of crystallinity on the material response

    Energy Technology Data Exchange (ETDEWEB)

    Ortiz, Rocio; Quintana, Iban; Etxarri, Jon [Manufacturing Processes Department, Fundacion TEKNIKER, Av. Otaola 20, 20600, Eibar, Guipuzcoa (Spain); Lejardi, Ainhoa; Sarasua, Jose-Ramon [Department of Mining and Metallurgy Engineering and Materials Science, School of Engineering, University of the Basque Country (EHU-UPV), Alameda de Urquijo s/n, 48013 Bilbao (Spain)

    2011-11-01

    The picosecond laser ablation of poly-L-lactide (PLLA) as a function of laser fluence and degree of crystallinity was examined. The ablation parameters and the surface modifications were analyzed under various irradiation conditions using laser wavelengths ranging from the ultraviolet through the visible. When processing the amorphous PLLA, both energy threshold and topography varied considerably depending on laser wavelength. Laser irradiation showed a reduction in the energy ablation threshold as the degree of crystallinity increased, probably related to photomechanical effects involved in laser ablation with ultra-short pulses and the lower stress accommodation behavior of semicrystalline polymers. In particular, cooperative chain motions are impeded by the higher degree of crystallinity, showing fragile mechanical behavior and lower energy dissipation. The experimental results on ablation rate versus laser energy showed that UV laser ablation on semicrystalline PLLA was more efficient than the visible ablation, i.e., it exhibits higher etch rates over a wide range of pulse energy conditions. These results were interpreted in terms of photo-thermal and photo-chemical response of polymers as a function of material micro-structure and incident laser wavelength. High quality micro-grooves were produced in amorphous PLLA, reveling the potential of ultra-fast laser processing technique in the field of micro-structuring biocompatible and biodegradable polymers for biomedical applications.

  15. Picosecond laser ablation of poly-L-lactide: Effect of crystallinity on the material response

    International Nuclear Information System (INIS)

    Ortiz, Rocio; Quintana, Iban; Etxarri, Jon; Lejardi, Ainhoa; Sarasua, Jose-Ramon

    2011-01-01

    The picosecond laser ablation of poly-L-lactide (PLLA) as a function of laser fluence and degree of crystallinity was examined. The ablation parameters and the surface modifications were analyzed under various irradiation conditions using laser wavelengths ranging from the ultraviolet through the visible. When processing the amorphous PLLA, both energy threshold and topography varied considerably depending on laser wavelength. Laser irradiation showed a reduction in the energy ablation threshold as the degree of crystallinity increased, probably related to photomechanical effects involved in laser ablation with ultra-short pulses and the lower stress accommodation behavior of semicrystalline polymers. In particular, cooperative chain motions are impeded by the higher degree of crystallinity, showing fragile mechanical behavior and lower energy dissipation. The experimental results on ablation rate versus laser energy showed that UV laser ablation on semicrystalline PLLA was more efficient than the visible ablation, i.e., it exhibits higher etch rates over a wide range of pulse energy conditions. These results were interpreted in terms of photo-thermal and photo-chemical response of polymers as a function of material micro-structure and incident laser wavelength. High quality micro-grooves were produced in amorphous PLLA, reveling the potential of ultra-fast laser processing technique in the field of micro-structuring biocompatible and biodegradable polymers for biomedical applications.

  16. Optimal behavior of responsive residential demand considering hybrid phase change materials

    International Nuclear Information System (INIS)

    Shafie-khah, M.; Kheradmand, M.; Javadi, S.; Azenha, M.; Aguiar, J.L.B. de; Castro-Gomes, J.; Siano, P.; Catalão, J.P.S.

    2016-01-01

    Highlights: • An operational model of HEM system incorporating with a hybrid PCM is proposed in this paper. • Incorporation of hybrid PCM mortar had a complementary effect on the proposed HEM system. • The proposed model ensures the technical and economic limits of batteries and electrical appliances. • The customer’s electricity cost can be reduced up to 48% by utilizing the proposed model. - Abstract: Due to communication and technology developments, residential consumers are enabled to participate in Demand Response Programs (DRPs), control their consumption and decrease their cost by using Household Energy Management (HEM) systems. On the other hand, capability of energy storage systems to improve the energy efficiency causes that employing Phase Change Materials (PCM) as thermal storage systems to be widely addressed in the building applications. In this paper, an operational model of HEM system considering the incorporation of more than one type of PCM in plastering mortars (hybrid PCM) is proposed not only to minimize the customer’s cost in different DRPs but also to guaranty the habitants’ satisfaction. Moreover, the proposed model ensures the technical and economic limits of batteries and electrical appliances. Different case studies indicate that implementation of hybrid PCM in the buildings can meaningfully affect the operational pattern of HEM systems in different DRPs. The results reveal that the customer’s electricity cost can be reduced up to 48% by utilizing the proposed model.

  17. The CERN antiproton target: hydrocode analysis of its core material dynamic response under proton beam impact

    CERN Document Server

    Martin, Claudio Torregrosa; Calviani, Marco; Muñoz-Cobo, José-Luis

    2016-01-01

    Antiprotons are produced at CERN by colliding a 26 GeV/c proton beam with a fixed target made of a 3 mm diameter, 55 mm length iridium core. The inherent characteristics of antiproton production involve extremely high energy depositions inside the target when impacted by each primary proton beam, making it one of the most dynamically demanding among high energy solid targets in the world, with a rise temperature above 2000 {\\deg}C after each pulse impact and successive dynamic pressure waves of the order of GPa's. An optimized redesign of the current target is foreseen for the next 20 years of operation. As a first step in the design procedure, this numerical study delves into the fundamental phenomena present in the target material core under proton pulse impact and subsequent pressure wave propagation by the use of hydrocodes. Three major phenomena have been identified, (i) the dominance of a high frequency radial wave which produces destructive compressive-to-tensile pressure response (ii) The existence of...

  18. Electric field responsive origami structures using electrostriction-based active materials

    Science.gov (United States)

    Ahmed, Saad; Arrojado, Erika; Sigamani, Nirmal; Ounaies, Zoubeida

    2015-04-01

    The objective of origami engineering is to combine origami principles with advanced materials to yield active origami shapes, which fold and unfold in response to external stimuli. We are investigating the use of P(VDF-TrFE-CTFE), a relaxor ferroelectric terpolymer, to realize origami-inspired folding and unfolding of structures and to actuate so-called action origami structures. To accomplish these two objectives, we have explored different approaches to the P(VDF-TrFECTFE) polymer actuator construction, ranging from unimorph to multilayered stacks. Electromechanical characterization of the terpolymer-based actuators is conducted with a focus on free strain, force-displacement and blocked force. Moreover dynamic thickness strains of P(VDF-TrFE-CTFE) terpolymer at different frequencies ranging from 0.1Hz to 10Hz is also measured. Quantifying the performance of terpolymer-based actuators is important to the design of action origami structures. Following these studies, action origami prototypes based on catapult, flapping butterfly wings and barking fox are actuated and characterization of these prototypes are conducted by studying impact of various parameters such as electric field magnitude and frequency, number of active layers, and actuator dimensions.

  19. Impact of Material and Architecture Model Parameters on the Failure of Woven Ceramic Matrix Composites (CMCs) via the Multiscale Generalized Method of Cells

    Science.gov (United States)

    Liu, Kuang C.; Arnold, Steven M.

    2011-01-01

    It is well known that failure of a material is a locally driven event. In the case of ceramic matrix composites (CMCs), significant variations in the microstructure of the composite exist and their significance on both deformation and life response need to be assessed. Examples of these variations include changes in the fiber tow shape, tow shifting/nesting and voids within and between tows. In the present work, the effects of many of these architectural parameters and material scatter of woven ceramic composite properties at the macroscale (woven RUC) will be studied to assess their sensitivity. The recently developed Multiscale Generalized Method of Cells methodology is used to determine the overall deformation response, proportional elastic limit (first matrix cracking), and failure under tensile loading conditions. The macroscale responses investigated illustrate the effect of architectural and material parameters on a single RUC representing a five harness satin weave fabric. Results shows that the most critical architectural parameter is weave void shape and content with other parameters being less in severity. Variation of the matrix material properties was also studied to illustrate the influence of the material variability on the overall features of the composite stress-strain response.

  20. Recent Advances in Stimuli-Responsive Photofunctional Materials Based on Accommodation of Chromophore into Layered Double Hydroxide Nanogallery

    Directory of Open Access Journals (Sweden)

    Wu Li

    2013-01-01

    Full Text Available The assembly of photofunctional molecules into host matrices has become an important strategy to achieve tunable fluorescence and to develop intelligent materials. The stimuli-responsive photofunctional materials based on chromophores-assembled layered double hydroxides (LDHs have received much attention from both academic and industry fields as a result of their advantages, such as high photo/thermal stability, easy processing, and well reversibility, which can construct new types of smart luminescent nanomaterials (e.g., ultrathin film and nanocomposite for sensor and switch applications. In this paper, external environmental stimuli have mainly involved physical (such as temperature, pressure, light, and electricity and chemical factors (such as pH and metal ion; recent progress on the LDH-based organic-inorganic stimuli-responsive materials has been summarized. Moreover, perspectives on further development of these materials are also discussed.

  1. Thermal Response of UHMWPE Materials in a Flash Flame Test Environment

    Science.gov (United States)

    2014-11-13

    protection. The UHMWPE fabric immediately began disintegrating during the flash flame exposure. During the test, one end of the UHMWPE fabric...UHMWPE material after the test. There were places where the fabric material appeared to have melted and re-solidified, creating areas of solid plastic ...and Observations The midscale test results showed that any direct flame on the UHMWPE materials will cause rapid disintegration of the material

  2. ARAC: a centralized computer-assisted emergency planning, response, and assessment system for atmospheric releases of toxic material

    International Nuclear Information System (INIS)

    Dickerson, M.H.; Knox, J.B.

    1987-01-01

    The Atmospheric Release Advisory Capability (ARAC) is an emergency planning, response, and assessment service, developed by the US Departments of Energy and Defense, and focused, thus far, on atmospheric releases of nuclear material. For the past 14 years ARAC has responded to over 150 accidents, potential accidents, and major exercises. The most notable accident responses are the COSMOS 954 reentry, the Three Mile Island (TMI-2) accident and subsequent purge of 85 Kr from the containment vessel, the recent UF 6 accident at the Kerr-McGee Plant, Gore, Oklahoma, and the Chernobyl nuclear reactor accident in the Soviet Union. Based on experience in the area of emergency response, developed during the past 14 years, this paper describes the cost effectiveness and other advantages of a centralized emergency planning, response, and assessment service for atmospheric releases of nuclear material

  3. ARAC: a centralized computer assisted emergency planning, response, and assessment system for atmospheric releases of toxic material

    International Nuclear Information System (INIS)

    Dickerson, M.H.; Knox, J.B.

    1986-10-01

    The Atmospheric Release Advisory Capability (ARAC) is an emergency planning, response, and assessment service, developed by the US Departments of Energy and Defense, and focused, thus far, on atmospheric releases of nuclear material. For the past 14 years ARAC has responded to over 150 accidents, potential accidents, and major exercises. The most notable accident responses are the COSMOS 954 reentry, the Three Mile Island (TMI-2) accident and subsequent purge of 85 Kr from the containment vessel, the recent UF 6 accident at the Kerr-McGee Plant, Gore, Oklahoma, and the Chernobyl nuclear reactor accident in the Soviet Union. Based on experience in the area of emergency response, developed during the past 14 years, this paper describes the cost effectiveness and other advantages of a centralized emergency planning, response, and assessment service for atmospheric releases of nuclear material

  4. Impact Testing of Stainless Steel Materials

    International Nuclear Information System (INIS)

    R. K. Blandford; D. K. Morton; T. E. Rahl; S. D. Snow

    2005-01-01

    Stainless steels are used for the construction of numerous spent nuclear fuel or radioactive material containers that may be subjected to high strains and moderate strain rates (10 to 200 per second) during accidental drop events. Mechanical characteristics of these materials under dynamic (impact) loads in the strain rate range of concern are not well documented. The goal of the work presented in this paper was to improve understanding of moderate strain rate phenomena on these materials. Utilizing a drop-weight impact test machine and relatively large test specimens (1/2-inch thick), initial test efforts focused on the tensile behavior of specific stainless steel materials during impact loading. Impact tests of 304L and 316L stainless steel test specimens at two different strain rates, 25 per second (304L and 316L material) and 50 per second (304L material) were performed for comparison to their quasi-static tensile test properties. Elevated strain rate stress-strain curves for the two materials were determined using the impact test machine and a ''total impact energy'' approach. This approach considered the deformation energy required to strain the specimens at a given strain rate. The material data developed was then utilized in analytical simulations to validate the final elevated stress-strain curves. The procedures used during testing and the results obtained are described in this paper

  5. Scaling impact and shock-compression response for porous materials: Application to planetary formation

    Science.gov (United States)

    Jeanloz, R.

    2016-12-01

    A thermodynamic model based on the Mie-Grüneisen equation of state does a good job of describing the response of porous materials to impact, so can provide insights into the accretion and cohesion of planetesimals too small to be significantly held together by gravity (e.g., tens of km or less in average diameter). The model identifies an offset in Hugoniot pressure (ΔPH) due to porosity that is found to be in agreement with experimental shock-compression measurements for samples having a wide range of initial porosities. Assuming the Grüneisen parameter (γ) is proportional to volume (γ/V = constant), the relative offset in Hugoniot pressure as a function of initial porosity (φ = 1 - V0/V0por) and compression (η = 1 - V/V0) is ΔPH/PH = γ0 φ/[2(1 - φ) - γ0 (φ + η(1 - φ))] where subscripts 0 and por represent zero-pressure (non-porous) conditions and a porous sample, respectively. This additional thermal pressure at a given volume is due to the extra internal energy and corresponding temperature increase associated with collapsing pores (Fig. 1: near-identical curves for φ = 0.001 and 0.01). This result can be interpreted as indicating that upon collapse individual pores create hot spots with temperatures of order 103-104K above the background, suggesting that impact into an initially porous target can result in cohesion due to partial melting and vaporization. Moreover, the waste heat associated with pore closure far exceeds the dissipation in shock loading of non-porous material, reflecting the ability of a porous target to absorb and dissipate impact energy. The Mie-Grüneisen model along with analysis of waste heat thus provides a scaling for planetesimal impact that might explain how rock and regolith accrete into a gravitationally bound planet. Fig. 1. Porosity-induced anomaly in Hugoniot temperature per unit of porosity, shown as a function of compression for samples with initial porosity φ = 0.001 (green), 0.01 (blue) and 0.1 (gold) assuming

  6. Reciprocity, passivity and causality in Willis materials.

    Science.gov (United States)

    Muhlestein, Michael B; Sieck, Caleb F; Alù, Andrea; Haberman, Michael R

    2016-10-01

    Materials that require coupling between the stress-strain and momentum-velocity constitutive relations were first proposed by Willis (Willis 1981 Wave Motion 3 , 1-11. (doi:10.1016/0165-2125(81)90008-1)) and are now known as elastic materials of the Willis type, or simply Willis materials. As coupling between these two constitutive equations is a generalization of standard elastodynamic theory, restrictions on the physically admissible material properties for Willis materials should be similarly generalized. This paper derives restrictions imposed on the material properties of Willis materials when they are assumed to be reciprocal, passive and causal. Considerations of causality and low-order dispersion suggest an alternative formulation of the standard Willis equations. The alternative formulation provides improved insight into the subwavelength physical behaviour leading to Willis material properties and is amenable to time-domain analyses. Finally, the results initially obtained for a generally elastic material are specialized to the acoustic limit.

  7. Thermally and Chemically responsive nanoporous materials for efficient capture of fission product gases.

    Energy Technology Data Exchange (ETDEWEB)

    Stroeve, Pieter; Faller, Roland

    2018-04-24

    The objective of this project was to develop robust, high-efficiency materials for capture of fission product gases such as He, Xe and Kr in scenarios relevant for both reactor fuels and reprocessing operations. The relevant environments are extremely harsh, encompassing temperatures up to 1500 °C, high levels of radiation, as well as potential exposures to highly-reactive chemicals such as nitric acid and organic solvents such as kerosene. The requirement for nanostructured capture materials is driven in part by the very short (few micron) diffusion distances for product gases in nuclear fuel.1-2 We achieved synthesis, characterization and detailed modeling of the materials. Although not all materials reviewed in this report will be feasible for the ultimate goal of integration in nuclear fuel, nevertheless each material studied has particular properties which will enable an optimized material to be efficiently developed and characterized.

  8. Quantifying the Mechanical Properties of Materials and the Process of Elastic-Plastic Deformation under External Stress on Material

    Directory of Open Access Journals (Sweden)

    Jan Valíček

    2015-11-01

    Full Text Available The paper solves the problem of the nonexistence of a new method for calculation of dynamics of stress-deformation states of deformation tool-material systems including the construction of stress-strain diagrams. The presented solution focuses on explaining the mechanical behavior of materials after cutting by abrasive waterjet technology (AWJ, especially from the point of view of generated surface topography. AWJ is a flexible tool accurately responding to the mechanical resistance of the material according to the accurately determined shape and roughness of machined surfaces. From the surface topography, it is possible to resolve the transition from ideally elastic to quasi-elastic and plastic stress-strain states. For detecting the surface structure, an optical profilometer was used. Based on the analysis of experimental measurements and the results of analytical studies, a mathematical-physical model was created and an exact method of acquiring the equivalents of mechanical parameters from the topography of surfaces generated by abrasive waterjet cutting and external stress in general was determined. The results of the new approach to the construction of stress-strain diagrams are presented. The calculated values agreed very well with those obtained by a certified laboratory VÚHŽ.

  9. Quantifying the Mechanical Properties of Materials and the Process of Elastic-Plastic Deformation under External Stress on Material

    Science.gov (United States)

    Valíček, Jan; Harničárová, Marta; Öchsner, Andreas; Hutyrová, Zuzana; Kušnerová, Milena; Tozan, Hakan; Michenka, Vít; Šepelák, Vladimír; Mitaľ, Dušan; Zajac, Jozef

    2015-01-01

    The paper solves the problem of the nonexistence of a new method for calculation of dynamics of stress-deformation states of deformation tool-material systems including the construction of stress-strain diagrams. The presented solution focuses on explaining the mechanical behavior of materials after cutting by abrasive waterjet technology (AWJ), especially from the point of view of generated surface topography. AWJ is a flexible tool accurately responding to the mechanical resistance of the material according to the accurately determined shape and roughness of machined surfaces. From the surface topography, it is possible to resolve the transition from ideally elastic to quasi-elastic and plastic stress-strain states. For detecting the surface structure, an optical profilometer was used. Based on the analysis of experimental measurements and the results of analytical studies, a mathematical-physical model was created and an exact method of acquiring the equivalents of mechanical parameters from the topography of surfaces generated by abrasive waterjet cutting and external stress in general was determined. The results of the new approach to the construction of stress-strain diagrams are presented. The calculated values agreed very well with those obtained by a certified laboratory VÚHŽ. PMID:28793645

  10. Material model for shear of the buffer - evaluation of laboratory test results

    International Nuclear Information System (INIS)

    Boergesson, Lennart; Dueck, Ann; Johannesson, Lars-Erik

    2010-12-01

    The report describes the material model of bentonite used for analysing a rock shear through a deposition hole. The old model used in SR-Can has been considerably changed. The new reference model that has been developed for SR-Site is described and motivated. The relevant properties of the buffer that affect the response to a rock shear are (in addition to the bentonite type) the density (which yields a swelling pressure), the shear strength, the stiffness before the maximum shear stress is reached and the shear rate, which also affects the shear strength. Since the shear caused by an earthquake is very fast and the hydraulic conductivity of the bentonite is very low there is no possibility for the pore water in the water saturated bentonite to be redistributed. Since the compressibility of water and particles are negligible, the bentonite can be modelled as a solid material that cannot change volume but only exhibit shear deformations. A proper and simple model that behaves accordingly is a model with von Mises' stress modelled as a function of the strain (stress-strain model). The model is elastic-plastic with an E-modulus that determines the behaviour until the material starts yielding whereupon the plastic strain is modelled as a function of von Mises' stress and added to the elastic strain. Included in the model is also a strain rate dependency of the stress-strain relation, which ranges between the strain rates 10 -6 1/s 3 1/s. The reference material model is derived from a large number of laboratory tests made on different bentonites at different strain rates, densities and with different techniques. Since it cannot be excluded that the exchangeable cat-ions in the Na-bentonite MX-80 is exchanged to calcium-ions the Ca-bentonite Deponit CaN is proposed to be used as reference material. The overall conclusion is that a relevant and probably also slightly conservative material model of Ca-converted MX-80 is derived, presented and well motivated

  11. Leptothrix sp sheaths modified with iron oxide particles: Magnetically responsive, high aspect ratio functional material

    Czech Academy of Sciences Publication Activity Database

    Šafařík, Ivo; Angelova, R.; Baldíková, E.; Pospíšková, K.; Šafaříková, Miroslava

    2017-01-01

    Roč. 71, February (2017), s. 1342-1346 ISSN 0928-4931 Institutional support: RVO:60077344 Keywords : Leptothrix * magnetic modification * iron oxide * high aspect ratio material Subject RIV: BM - Solid Matter Physics ; Magnetism OBOR OECD: Materials engineering Impact factor: 4.164, year: 2016

  12. On the Constitutive Response Characterization for Composite Materials Via Data-Driven Design Optimization

    Science.gov (United States)

    John G. Michopoulos; John G. Hermanson; Athanasios lliopoulos; Samuel Lambrakos; Tomonari Furukawa

    2011-01-01

    In the present paper we focus on demonstrating the use of design optimization for the constitutive characterization of anisotropic material systems such as polymer matrix composites, with or without damage. All approaches are based on the availability of experimental data originating from mechatronic material testing systems that can expose specimens to...

  13. Study on dynamic behavior of fusion reactor materials and their response to variable and complex irradiation environment

    International Nuclear Information System (INIS)

    Abe, K.; Kohyama, A.; Namba, C.; Wiffen, F.W.; Jones, R.H.

    2001-01-01

    A Japan-USA Program of irradiation experiments for fusion research, 'JUPITER', has been established as a 6 year program from 1995 to 2000. The goal is to study the dynamic behavior of fusion reactor materials and their response to variable and complex irradiation environment using fission reactors. The irradiation experiments in this program include low activation structural materials, functional ceramics and other innovative materials. The experimental data are analyzed by theoretical modeling and computer simulation to integrate the above effects. The irradiation capsules for in-situ measurement and varying temperature were developed successfully. It was found that insulating ceramics were worked up to 3 dpa. The property changes and related issues in low activation structural materials were summarized. (author)

  14. Soft network materials with isotropic negative Poisson's ratios over large strains.

    Science.gov (United States)

    Liu, Jianxing; Zhang, Yihui

    2018-01-31

    Auxetic materials with negative Poisson's ratios have important applications across a broad range of engineering areas, such as biomedical devices, aerospace engineering and automotive engineering. A variety of design strategies have been developed to achieve artificial auxetic materials with controllable responses in the Poisson's ratio. The development of designs that can offer isotropic negative Poisson's ratios over large strains can open up new opportunities in emerging biomedical applications, which, however, remains a challenge. Here, we introduce deterministic routes to soft architected materials that can be tailored precisely to yield the values of Poisson's ratio in the range from -1 to 1, in an isotropic manner, with a tunable strain range from 0% to ∼90%. The designs rely on a network construction in a periodic lattice topology, which incorporates zigzag microstructures as building blocks to connect lattice nodes. Combined experimental and theoretical studies on broad classes of network topologies illustrate the wide-ranging utility of these concepts. Quantitative mechanics modeling under both infinitesimal and finite deformations allows the development of a rigorous design algorithm that determines the necessary network geometries to yield target Poisson ratios over desired strain ranges. Demonstrative examples in artificial skin with both the negative Poisson's ratio and the nonlinear stress-strain curve precisely matching those of the cat's skin and in unusual cylindrical structures with engineered Poisson effect and shape memory effect suggest potential applications of these network materials.

  15. Hydrodynamic effects of eroded materials on response of plasma-facing component during a tokamak disruption

    International Nuclear Information System (INIS)

    Hassanein, A.; Konkashbaev, I.

    1999-01-01

    Loss of plasma confinement causes surface and structural damage to plasma-facing materials (PFMs) and remains a major obstacle for tokamak reactors. The deposited plasma energy results in surface erosion and structural failure. The surface erosion consists of vaporization, spallation, and liquid splatter of metallic materials, while the structural damage includes large temperature increases in structural materials and at the interfaces between surface coatings and structural members. Comprehensive models (contained in the HEIGHTS computer simulation package) are being used self-consistently to evaluate material damage. Splashing mechanisms occur as a result of volume bubble boiling and liquid hydrodynamic instabilities and brittle destruction mechanisms of nonmelting materials. The effect of macroscopic erosion on total mass losses and lifetime is evaluated. The macroscopic erosion products may further protect PFMs from severe erosion (via the droplet-shielding effect) in a manner similar to that of the vapor shielding concept

  16. Stakeholders' Responses to CSR Tradeoffs: When Other-Orientation and Trust Trump Material Self-Interest.

    Science.gov (United States)

    Bridoux, Flore; Stofberg, Nicole; Den Hartog, Deanne

    2015-01-01

    When investing in corporate social responsibility (CSR), managers may strive for a win-win scenario where all stakeholders end up better off, but they may not always be able to avoid trading off stakeholders' interests. To provide guidance to managers who have to make tradeoffs, this study used a vignette-based experiment to explore stakeholders' intention to associate with a firm (i.e., buy from or become an employee) that trades off CSR directed at the stakeholders' own group (self-directed CSR) and CSR directed at another stakeholder group (other-directed CSR). Results show that stakeholders were not systematically more attracted to a firm that favors their own group over another stakeholder group. Specifically, stakeholders' other-orientation moderated their reaction to tradeoffs: stakeholders higher on other-orientation were willing to forego some material benefits to associate with a firm that treated suppliers in developing countries significantly better than its competitors, whereas stakeholders lower on other-orientation were more attracted to a firm favoring their own stakeholder group. Other-orientation also moderated reactions to tradeoffs involving the environment, although high CSR directed at the environment did not compensate for low self-directed CSR even for stakeholders higher on other-orientation. Second, the vignette study showed that trust mediated the relationship between tradeoffs and stakeholders' reactions. The study contributes first and foremost to the burgeoning literature on CSR tradeoffs and to the multimotive approach to CSR, which claims that other motives can drive stakeholders' reactions to CSR in addition to self-interest. First, it provides further evidence that studying CSR tradeoffs is important to understand both (prospective) employees' and customers' reactions to CSR-related activities. Second, it identifies other-orientation as a motive-related individual difference that explains heterogeneity in stakeholders' reactions to

  17. Stakeholders’ responses to CSR tradeoffs: When other-orientation and trust trump material self-interest

    Directory of Open Access Journals (Sweden)

    Flore eBridoux

    2016-01-01

    Full Text Available When investing in corporate social responsibility (CSR, managers may strive for a win-win scenario where all stakeholders end up better off, but they may not always be able to avoid trading off stakeholders’ interests. To provide guidance to managers who have to make tradeoffs, this study used a vignette-based experiment to explore stakeholders’ intention to associate with a firm (i.e., buy from or become an employee that trades off CSR directed at the stakeholders’ own group (self-directed CSR and CSR directed at another stakeholder group (other-directed CSR. Results show that stakeholders were not systematically more attracted to a firm that favors their own group over another stakeholder group. Specifically, stakeholders’ other-orientation moderated their reaction to tradeoffs: stakeholders higher on other-orientation were willing to forego some material benefits to associate with a firm that treated suppliers in developing countries significantly better than its competitors, whereas stakeholders lower on other-orientation were more attracted to a firm favoring their own stakeholder group. Other-orientation also moderated reactions to tradeoffs involving the environment, although high CSR directed at the environment did not compensate for low self-directed CSR even for stakeholders higher on other-orientation. Second, the vignette study showed that trust mediated the relationship between tradeoffs and stakeholders’ reactions. The study contributes first and foremost to the burgeoning literature on CSR tradeoffs and to the multimotive approach to CSR, which claims that other motives can drive stakeholders’ reactions to CSR in addition to self-interest. First, it provides further evidence that studying CSR tradeoffs is important to understand both (prospective employees’ and customers’ reactions to CSR-related activities. Second, it identifies other-orientation as a motive-related individual difference that explains

  18. Stakeholders' Responses to CSR Tradeoffs: When Other-Orientation and Trust Trump Material Self-Interest

    Science.gov (United States)

    Bridoux, Flore; Stofberg, Nicole; Den Hartog, Deanne

    2016-01-01

    When investing in corporate social responsibility (CSR), managers may strive for a win-win scenario where all stakeholders end up better off, but they may not always be able to avoid trading off stakeholders' interests. To provide guidance to managers who have to make tradeoffs, this study used a vignette-based experiment to explore stakeholders' intention to associate with a firm (i.e., buy from or become an employee) that trades off CSR directed at the stakeholders' own group (self-directed CSR) and CSR directed at another stakeholder group (other-directed CSR). Results show that stakeholders were not systematically more attracted to a firm that favors their own group over another stakeholder group. Specifically, stakeholders' other-orientation moderated their reaction to tradeoffs: stakeholders higher on other-orientation were willing to forego some material benefits to associate with a firm that treated suppliers in developing countries significantly better than its competitors, whereas stakeholders lower on other-orientation were more attracted to a firm favoring their own stakeholder group. Other-orientation also moderated reactions to tradeoffs involving the environment, although high CSR directed at the environment did not compensate for low self-directed CSR even for stakeholders higher on other-orientation. Second, the vignette study showed that trust mediated the relationship between tradeoffs and stakeholders' reactions. The study contributes first and foremost to the burgeoning literature on CSR tradeoffs and to the multimotive approach to CSR, which claims that other motives can drive stakeholders' reactions to CSR in addition to self-interest. First, it provides further evidence that studying CSR tradeoffs is important to understand both (prospective) employees' and customers' reactions to CSR-related activities. Second, it identifies other-orientation as a motive-related individual difference that explains heterogeneity in stakeholders' reactions to

  19. A Generalized Orthotropic Elasto-Plastic Material Model for Impact Analysis

    Science.gov (United States)

    Hoffarth, Canio

    Composite materials are now beginning to provide uses hitherto reserved for metals in structural systems such as airframes and engine containment systems, wraps for repair and rehabilitation, and ballistic/blast mitigation systems. These structural systems are often subjected to impact loads and there is a pressing need for accurate prediction of deformation, damage and failure. There are numerous material models that have been developed to analyze the dynamic impact response of polymer matrix composites. However, there are key features that are missing in those models that prevent them from providing accurate predictive capabilities. In this dissertation, a general purpose orthotropic elasto-plastic computational constitutive material model has been developed to predict the response of composites subjected to high velocity impacts. The constitutive model is divided into three components - deformation model, damage model and failure model, with failure to be added at a later date. The deformation model generalizes the Tsai-Wu failure criteria and extends it using a strain-hardening-based orthotropic yield function with a non-associative flow rule. A strain equivalent formulation is utilized in the damage model that permits plastic and damage calculations to be uncoupled and capture the nonlinear unloading and local softening of the stress-strain response. A diagonal damage tensor is defined to account for the directionally dependent variation of damage. However, in composites it has been found that loading in one direction can lead to damage in multiple coordinate directions. To account for this phenomena, the terms in the damage matrix are semi-coupled such that the damage in a particular coordinate direction is a function of the stresses and plastic strains in all of the coordinate directions. The overall framework is driven by experimental tabulated temperature and rate-dependent stress-strain data as well as data that characterizes the damage matrix and failure

  20. Development and Sliding Wear Response of Epoxy Composites Filled with Coal Mine Overburden Material

    Science.gov (United States)

    Das, Prithika; Satapathy, Alok; Mishra, M. K.

    2018-03-01

    The paper reports on development and characterization of epoxy based composites filled with micro-sized mine overburden material. Coal mine overburden material is typically highly heterogeneous and is considered as waste material. For excavating each ton of coal, roughly 5 tons of overburden materials are removed and is dumped nearby occupying large space. Gainful utilization of this waste is a major challenge. In the present work, this material is used as filler materials in making a new class of epoxy matrix composites. Composites with different weight proportions of fillers (0, 10, 20, 30 and 40) wt. % are prepared by hand layup technique. Compression tests are performed as per corresponding ASTM standards to assess the compressive strength of these composites. Further, dry sliding tests are performed following ASTM G99 standards using a pin on disk machine. A design of experiment approach based on Taguchi’s L16 orthogonal arrays is adopted. Tests are performed at different sliding velocities for multiple sliding distances under varying normal loads. Specific wear rates of the composites under different test conditions are obtained. The analysis of the test results revealed that the filler content and the sliding velocity are the most predominant control factors affecting the wear rate. This work thus, opens up a new avenue for the value added utilization of coal mine overburden material.

  1. Polymer-Block-Polypeptides and Polymer-Conjugated Hybrid Materials as Stimuli-Responsive Nanocarriers for Biomedical Applications.

    Science.gov (United States)

    John, Johnson V; Johnson, Renjith P; Heo, Min Seon; Moon, Byeong Kyu; Byeon, Seong Jin; Kim, Il

    2015-01-01

    Stimuli-responsive nanocarriers are a class of soft materials that includes natural polymers, synthetic polymers, and polypeptides. Recently, modern synthesis tools such as atom transfer radical polymerization, reversible addition-fragmentation chain transfer polymerization, nitroxide-mediated radical polymerization, ring-opening polymerization of α-amino acid N-carboxyanhydrides, and various "click" chemistry strategies were simultaneously employed for the design and synthesis of nanosized drug delivery vehicles. Importantly, the research focused on the improvement of the nanocarrier targetability and the site-specific, triggered release of therapeutics with high drug loading efficiency and minimal drug leakage during the delivery to specific targets. In this context, nanocarriers responsive to common stimuli such as pH, temperature, redox potential, light, etc. have been widely used for the controlled delivery of therapeutics to pathological sites. Currently, different synthesis and self-assembly strategies improved the drug loading efficacy and targeted delivery of therapeutic agents to the desired site. In particular, polypeptide-containing hybrid materials have been developed for the controlled delivery of therapeutic agents. Therefore, stimuli-sensitive synthetic polypeptide-based materials have been extensively investigated in recent years. This review focuses on recent advances in the development of polymer-block-polypeptides and polymer-conjugated hybrid materials that have been designed and evaluated for various stimuli-responsive drug and gene delivery applications.

  2. Role of proper response schemes, legislation and regional cooperation in combating illicit trafficking of nuclear materials in developing countries

    International Nuclear Information System (INIS)

    Sterzov, A.

    2002-01-01

    Full text: The suitable geographical situation on the crossroad between Europe, the former Soviet Union and the Middle East puts Bulgaria into the stream of many illegal traffics - people, arms, drugs etc. The illicit traffic of nuclear and radioactive materials is a serious violation of nonproliferation laws as well as a risk for the health of the population. Criminal diversion of fissile materials could lead to the potential construction of nuclear weapon or applied with conventional explosives the radioactive material could pose a threat to dwelling places, water supplies etc. The traffic of nuclear and radioactive materials in Bulgaria can be divided in two main parts -- internal and transit. I. Internal traffic The internal traffic consisted of stolen radioactive sources mainly imported with the Soviet equipment from companies or plants that were privatized or stopped functioning due to the economic changes in the country. There there were attempts to divert and transport materials from the Uranium mining industry including different amounts of 'yellow cake', depleted Uranium containers or shielding. These devices consisted of level and dense meters, irradiation devices, removing static electricity, smoke detectors etc. mainly containing the isotopes Cs-137, Co-60, Ir-192, Ra-226, Am-241 etc. II. External traffic The external traffic of illicit nuclear materials is connected with the transfer of raw materials and expensive metals from the former Soviet Union towards Western Europe and the Middle East. This traffic included Al, Os, Cs, Sc, Rare earth elements, Red Mercury, Pu, Enriched U. The traffic of the last three items is of greatest concern and should be addressed with highest priority. III. Response to the illicit traffic of nuclear materials The detection of both the internal and external traffic raises serious problems to the Bulgarian controlling organs both for equipment and qualified personnel at the borders and inside the country. The creation of

  3. Developing a highway emergency response plan for incidents involving hazardous materials, second edition, March 1992

    International Nuclear Information System (INIS)

    Anon.

    1992-01-01

    This provides minimum guidelines for developing an emergency response plan for incidents involving hazardous liquid hydrocarbons, such as gasoline and crude oil, transported in MC 306/DOT 406 and MC 307/DOT 407 aluminum cargo tanks and for coordinating and cooperating with local, state, and federal officials. This publication covers response plan priorities, personnel training, special equipment, media relations, environmental relations, and post-response activities. The apprendixes to this recommended practice outline a highway emergency response plan and suggest a procedure for removing liquid hydrocarbons from overturned cargo tanks and righting the tank vehicles

  4. Responsive hydrogels--structurally and dimensionally optimized smart frameworks for applications in catalysis, micro-system technology and material science.

    Science.gov (United States)

    Döring, Artjom; Birnbaum, Wolfgang; Kuckling, Dirk

    2013-09-07

    Although the technological and scientific importance of functional polymers has been well established over the last few decades, the most recent focus that has attracted much attention has been on stimuli-responsive polymers. This group of materials is of particular interest due to its ability to respond to internal and/or external chemico-physical stimuli, which is often manifested as large macroscopic responses. Aside from scientific challenges of designing stimuli-responsive polymers, the main technological interest lies in their numerous applications ranging from catalysis through microsystem technology and chemomechanical actuators to sensors that have been extensively explored. Since the phase transition phenomenon of hydrogels is theoretically well understood advanced materials based on the predictions can be prepared. Since the volume phase transition of hydrogels is a diffusion-limited process the size of the synthesized hydrogels is an important factor. Consistent downscaling of the gel size will result in fast smart gels with sufficient response times. In order to apply smart gels in microsystems and sensors, new preparation techniques for hydrogels have to be developed. For the up-coming nanotechnology, nano-sized gels as actuating materials would be of great interest.

  5. The Response of Simple Polymer Structures Under Dynamic Loading

    Science.gov (United States)

    Proud, William; Ellison, Kay; Yapp, Su; Cole, Cloe; Galimberti, Stefano; Institute of Shock Physics Team

    2017-06-01

    The dynamic response of polymeric materials has been widely studied with the effects of degree of crystallinity, strain rate, temperature and sample size being commonly reported. This study uses a simple PMMA structure, a right cylindrical sample, with structural features such as holes. The features are added an varied in a systematic fashion. Samples were dynamically loaded using a Split Hopkinson Pressure Bar up to failure. The resulting stress-strain curves are presented showing the change in sample response. The strain to failure is shown to increase initially with the presence of holes, while failure stress is relatively unaffected. The fracture patterns seen in the failed samples change, with tensile cracks, Hertzian cones, shear effects being dominant for different holes sizes and geometries. The sample were prepared by laser cutting and checked for residual stress before experiment. The data is used to validate predictive model predictions where material, structure and damage are included.. The Institute of Shock Physics acknowledges the support of Imperial College London and the Atomic Weapons Establishment.

  6. Representations for implicit constitutive relations describing non-dissipative response of isotropic materials

    Science.gov (United States)

    Gokulnath, C.; Saravanan, U.; Rajagopal, K. R.

    2017-12-01

    A methodology for obtaining implicit constitutive representations involving the Cauchy stress and the Hencky strain for isotropic materials undergoing a non-dissipative process is developed. Using this methodology, a general constitutive representation for a subclass of implicit models relating the Cauchy stress and the Hencky strain is obtained for an isotropic material with no internal constraints. It is shown that even for this subclass, unlike classical Green elasticity, one has to specify three potentials to relate the Cauchy stress and the Hencky strain. Then, a procedure to obtain implicit constitutive representations for isotropic materials with internal constraints is presented. As an illustration, it is shown that for incompressible materials the Cauchy stress and the Hencky strain could be related through a single potential. Finally, constitutive approximations are obtained when the displacement gradient is small.

  7. Material response reconstruction of ablative TPS using accurate boundary layer modeling

    Data.gov (United States)

    National Aeronautics and Space Administration — For hypersonic atmospheric entry missions, charring ablators are often used. These materials are made of non-pyrolyzing matrices (carbon, ceramic, etc.) combined...

  8. Electrical resistivity response due to elastic-plastic deformations

    International Nuclear Information System (INIS)

    Stout, R.B.

    1987-01-01

    The electrical resistivity of many materials is sensitive to changes in the electronic band configurations surrounding the atoms, changes in the electron-phonon interaction cross-sections, and changes in the density of intrinsic defect structures. These changes are most directly dependent on interatomic measures of relative deformation. For this reason, a model for resistivity response is developed in terms of interatomic measures of relative deformation. The relative deformation consists of two terms, a continuous function to describe the recoverable displacement between two atoms in the atomic lattice structure and a functional to describe the nonrecoverable displacement between two atoms as a result of interatomic discontinuities from dislocation kinetics. This model for resistivity extends the classical piezoresistance representation and relates electric resistance change directly to physical mechanisms. An analysis for the resistivity change of a thin foil ideally embedded in a material that undergoes elastic-plastic deformation is presented. For the case of elastic deformations, stress information in the material surrounding the thin foil is inferred for the cases of pure strain coupling boundary conditions, pure stress coupling boundary conditions, and a combination of stress-strain coupling boundary conditions. 42 refs., 4 figs

  9. An Overview of Mechanical Properties and Material Modeling of Polylactide (PLA) for Medical Applications.

    Science.gov (United States)

    Bergström, Jörgen S; Hayman, Danika

    2016-02-01

    This article provides an overview of the connection between the microstructural state and the mechanical response of various bioresorbable polylactide (PLA) devices for medical applications. PLLA is currently the most commonly used material for bioresorbable stents and sutures, and its use is increasing in many other medical applications. The non-linear mechanical response of PLLA, due in part to its low glass transition temperature (T g ≈ 60 °C), is highly sensitive to the molecular weight and molecular orientation field, the degree of crystallinity, and the physical aging time. These microstructural parameters can be tailored for specific applications using different resin formulations and processing conditions. The stress-strain, deformation, and degradation response of a bioresorbable medical device is also strongly dependent on the time history of applied loads and boundary conditions. All of these factors can be incorporated into a suitable constitutive model that captures the multiple physics that are involved in the device response. Currently developed constitutive models already provide powerful computations simulation tools, and more progress in this area is expected to occur in the coming years.

  10. Dynamic compressive response of wrought and additive manufactured 304L stainless steels

    Directory of Open Access Journals (Sweden)

    Nishida Erik

    2015-01-01

    Full Text Available Additive manufacturing (AM technology has been developed to fabricate metal components that include complex prototype fabrication, small lot production, precision repair or feature addition, and tooling. However, the mechanical response of the AM materials is a concern to meet requirements for specific applications. Differences between AM materials as compared to wrought materials might be expected, due to possible differences in porosity (voids, grain size, and residual stress levels. When the AM materials are designed for impact applications, the dynamic mechanical properties in both compression and tension need to be fully characterized and understood for reliable designs. In this study, a 304L stainless steel was manufactured with AM technology. For comparison purposes, both the AM and wrought 304L stainless steels were dynamically characterized in compression Kolsky bar techniques. They dynamic compressive stress-strain curves were obtained and the strain rate effects were determined for both the AM and wrought 304L stainless steels. A comprehensive comparison of dynamic compressive response between the AM and wrought 304L stainless steels was performed. SAND2015-0993 C.

  11. Empirical Model Development for Predicting Shock Response on Composite Materials Subjected to Pyroshock Loading. Volume 2, Part 1; Appendices

    Science.gov (United States)

    Gentz, Steven J.; Ordway, David O.; Parsons, David S.; Garrison, Craig M.; Rodgers, C. Steven; Collins, Brian W.

    2015-01-01

    The NASA Engineering and Safety Center (NESC) received a request to develop an analysis model based on both frequency response and wave propagation analyses for predicting shock response spectrum (SRS) on composite materials subjected to pyroshock loading. The model would account for near-field environment (approximately 9 inches from the source) dominated by direct wave propagation, mid-field environment (approximately 2 feet from the source) characterized by wave propagation and structural resonances, and far-field environment dominated by lower frequency bending waves in the structure. This document contains appendices to the Volume I report.

  12. On the influence of particle morphology on the post-impact ballistic response of ceramic armour materials

    Science.gov (United States)

    Hameed, Amer; Appleby-Thomas, Gareth; Wood, David; Jaansalu, Kevin

    2015-06-01

    Recent studies have shown evidence that the ballistic-resistance of fragmented (comminuted) ceramics is independent of the original strength of the material. In particular, experimental investigations into the ballistic behaviour of such fragmented ceramics have indicated that this response is correlated to shattered ceramic morphology. This suggests that careful control of ceramic microstructure - and therefore failure paths - might provide a route to optimise post-impact ballistic performance, thereby enhancing multi-hit capability. In this study, building on previous in-house work, ballistic tests were conducted using pre-formed `fragmented-ceramic' analogues based around three morphologically differing (but chemically identical) alumina feedstock materials compacted into target `pucks. In an evolution of previous work, variation of target thickness provided additional insight into an apparent morphology-based contribution to ballistic response.

  13. NRC's rulemaking to require materials licensees to be financially responsible for cleanup of accidental releases

    International Nuclear Information System (INIS)

    Seeman, M.J.

    1987-01-01

    On June 7, 1985, the US Nuclear Regulatory Commission (NRC) published an advance notice of proposed rulemaking (ANPRM) in the Federal Register to address funding for cleanup of accidents and unexpected decontamination by certain materials licensees. The NRC asked for public comment to help them determine whether to amend its regulations to require certain materials and fuel cycle licensees to demonstrate that they possess adequate financial means to pay for cleanup of accidental releases of radioactive materials. If licensees lack adequate financial resources and funds are to available for prompt cleanup, the consequences could be potentially significant for the public, the licencee and the federal government. The purpose of this paper is to explain the purpose and scope of the Commission's proposed regulatory action, as well as describing several accidents that made the Commission consider this action. Additionally, the paper will address other regulatory precedents. Finally, the paper will conclude by generally characterizing the public comments and items of concern raised by commenters

  14. Ice911: Developing an Effective Response to Climate Change in Earth's Cryosphere using High Albedo Materials

    Science.gov (United States)

    Field, L. A.; Wadhams, P.; Root, T.; Chetty, S.; Kammen, D. M.; Venkatesh, S.; van der Heide, D.; Baum, E.

    2012-12-01

    We are developing a localized surface albedo modification technique which shows promise for preserving ice and snow using inexpensive and environmentally benign floating materials. The approach has been developed with aims including preservation of polar and glacial ice, snow, permafrost and polar habitat,and keeping water cooler, using a localized and ecologically respectful "planetary band-aid" that can be deployed quickly and can be removed once it is no longer needed. The method has been tested at small scale using various material sets over several years, including four Winter/Spring seasons at sites including California's San Francisco Bay Area and Sierra Nevada Mountains, and a Canadian lake. The materials can passively float and in granular form can be easily deployed as a "monolayer" and/or corralled in the desired locations. They have been shown to reduce solar heat absorption in the underlying water in small test pools by nearly 200 Watts/m2 in California summer daytime conditions, and 2 to 11 degree-C reductions in water temperatures have been logged over the course of a day. The materials have a cost of roughly of $11.15/kW-hour (of reflected solar energy that would otherwise have heated the underlying water) for one day. Over a two-month summer period, the materials cost would be roughly eighteen cents/kW-hour of reflected solar energy, and work is ongoing to reduce costs further. Material deployments in a sheet form were used on a California mountain lake in Winter/Spring 2010-2011 to successfully demonstrate over a larger scale that properly engineered materials are effective in aiding snow and ice retention. Over the course of several days during the melting season, we typically observed differences of 70 cm greater snow retention under a Teslin sheet compared to the uncovered control areas. However, sheets tend to act as sails, requiring special measures to remain stable. The most recent season's experimentation saw further evolution in the

  15. Micromechanical modeling of the cement-bone interface: the effect of friction, morphology and material properties on the micromechanical response

    OpenAIRE

    Janssen, Dennis; Mann, Kenneth A.; Verdonschot, Nico

    2008-01-01

    In order to gain insight into the micro-mechanical behavior of the cement-bone interface, the effect of parametric variations of frictional, morphological and material properties on the mechanical response of the cement-bone interface were analyzed using a finite element approach. Finite element models of a cement-bone interface specimen were created from micro-computed tomography data of a physical specimen that was sectioned from an in vitro cemented total hip arthroplasty. In five models t...

  16. Joint research and development on toxic-material emergency response between ENEA and LLNL. 1982 progress report

    International Nuclear Information System (INIS)

    Gudiksen, P.; Lange, R.; Dickerson, M.; Sullivan, T.; Rosen, L.; Walker, H.; Boeri, G.B.; Caracciolo, R.; Fiorenza, R.

    1982-11-01

    A summary is presented of current and future cooperative studies between ENEA and LLNL researchers designed to develop improved real-time emergency response capabilities for assessing the environmental consequences resulting from an accidental release of toxic materials into the atmosphere. These studies include development and evaluation of atmospheric transport and dispersion models, interfacing of data processing and communications systems, supporting meteorological field experiments, and integration of radiological measurements and model results into real-time assessments

  17. In vitro degradation and cell response of calcium carbonate composite ceramic in comparison with other synthetic bone substitute materials

    International Nuclear Information System (INIS)

    He, Fupo; Zhang, Jing; Yang, Fanwen; Zhu, Jixiang; Tian, Xiumei; Chen, Xiaoming

    2015-01-01

    The robust calcium carbonate composite ceramics (CC/PG) can be acquired by fast sintering calcium carbonate at a low temperature (650 °C) using a biocompatible, degradable phosphate-based glass (PG) as sintering agent. In the present study, the in vitro degradation and cell response of CC/PG were assessed and compared with 4 synthetic bone substitute materials, calcium carbonate ceramic (CC), PG, hydroxyapatite (HA) and β-tricalcium phosphate (β-TCP) ceramics. The degradation rates in decreasing order were as follows: PG, CC, CC/PG, β-TCP, and HA. The proliferation of rat bone mesenchymal stem cells (rMSCs) cultured on the CC/PG was comparable with that on CC and PG, but inferior to HA and β-TCP. The alkaline phosphatase (ALP) activity of rMSCs on CC/PG was lower than PG, comparable with β-TCP, but higher than HA. The rMSCs on CC/PG and PG had enhanced gene expression in specific osteogenic markers, respectively. Compared to HA and β-TCP, the rMSCs on the CC/PG expressed relatively lower level of collagen I and runt-related transcription factor 2, but showed more considerable expression of osteopontin. Although CC, PG, HA, and β-TCP possessed impressive performances in some specific aspects, they faced extant intrinsic drawbacks in either degradation rate or mechanical strength. Based on considerable compressive strength, moderate degradation rate, good cell response, and being free of obvious shortcoming, the CC/PG is promising as another choice for bone substitute materials. - Highlights: • A calcium carbonate composite ceramic (CC/PG) was acquired. • The in vitro degradation and cell response of CC/PG were compared to 4 materials. • The CC/PG showed moderate degradation rate. • The CC/PG exhibited good cell response. • The CC/PG was free of obvious drawback compared to other materials

  18. Corrosion response of nuclear reactor materials to mixtures of decontamination reagents

    International Nuclear Information System (INIS)

    Speranzini, R.A.; Burchart, P.A.; Kanhai, K.A.

    1989-01-01

    An experimental study of the corrosiveness of mixtures of citric acid, oxalic acid, and EDTA to nuclear reactor materials was undertaken. Specimens of type 304 stainless steel (SS), type 410 SS, carbon steel (CS) 1018 and A508, and heat-treated alloy 600 were suspended in recirculating mixtures of two or more combinations of citric acid, oxalic acid, and EDTA at temperatures of 90 C or 117 C for 22 hours. The results suggest that removal of oxalic acid from decontamination solutions should lower the corrosiveness of the solutions to nuclear reactor materials, particularly types 304 SS and 410 SS

  19. Development of a General Shocked-Materials-Response Description for Simulations

    Energy Technology Data Exchange (ETDEWEB)

    Steven M. Valone

    2000-07-01

    This report outlines broad modeling issues pertaining to polymeric materials behavior under detonation conditions. Models applicable system wide are necessary to cope with the broad range of polymers and complex composite forms that can appear in Laboratory weapons systems. Nine major topics are discussed to span the breadth of materials, forms, and physical phenomena encountered when shocking polymers and foams over wide ranges of temperatures, pressures, shock strengths, confinement conditions, and geometries. The recommendations for directions of more intensive investigation consider physical fidelity, computational complexity, and application over widely varying physical conditions of temperature, pressure, and shock strength.

  20. Towards the robotic characterization of the constitutive response of composite materials

    Science.gov (United States)

    John G. Michopoulos; John C. Hermanson; Tomonari Furukawa

    2008-01-01

    A historical and technical overview of a paradigm for automating research procedures on the area of constitutive identification of composite materials is presented. Computationally controlled robotic, multiple degree-of-freedom mechatronic systems are used to accelerate the rate of performing data-collecting experiments along loading paths defined in multidimensional...

  1. Doorways III: Teacher Reference Materials. On School-Related Gender-Based Violence Prevention and Response

    Science.gov (United States)

    US Agency for International Development, 2009

    2009-01-01

    The Doorways training program was designed by the U.S. Agency for International Development (USAID)-funded Safe Schools Program (Safe Schools) to enable teachers, community members and students to prevent and respond to school-related gender-based violence (SRGBV). This booklet, "Doorways III: Teacher Reference Materials on School-Related…

  2. Law and Responsibilities (Law-Related Education Materials) 1982-83. Okeechobee County.

    Science.gov (United States)

    Allen, Rodney F., Ed.

    Teacher-developed materials for legal education in elementary and junior high schools in Florida are presented. The lessons focus on the consequences of crime and rule-breaking in terms of the law and penal systems, the victim and loved ones, the criminal and loved ones (as victims, too), and the community, which suffers and pays the costs. In the…

  3. Applicability of a valence fluctuation model to the observed physical property response of actinide materials

    International Nuclear Information System (INIS)

    Sandenaw, T.A.

    1978-01-01

    It is shown that the physical property behavior of the light actinide elements, U, Np, and Pu, and certain of their alloys, is like that of known mixed-valence, R.E. metallic compounds. It is inferred that interconfiguration fluctuation (ICF) theory should also be applicable to actinide materials

  4. Audiovisual Material as Educational Innovation Strategy to Reduce Anxiety Response in Students of Human Anatomy

    Science.gov (United States)

    Casado, Maria Isabel; Castano, Gloria; Arraez-Aybar, Luis Alfonso

    2012-01-01

    This study presents the design, effect and utility of using audiovisual material containing real images of dissected human cadavers as an innovative educational strategy (IES) in the teaching of Human Anatomy. The goal is to familiarize students with the practice of dissection and to transmit the importance and necessity of this discipline, while…

  5. Temperature dependence of the elastic constant of Borassus Flabellifier 'BF' material by acoustic response

    International Nuclear Information System (INIS)

    Phadke, Sushil; DShrivastava, B; Dagaonkar, N; Mishra, Ashutosh

    2012-01-01

    The homogeneous continuous materials are widely used for many structural applications. Migrations of atoms or molecules are the mechanism of mechanical and kinetic processes in materials for their synthesis processing as well as for their structural evolutions. The elastic constant of solids provides valuable information on their mechanical and dynamical properties. In particular, they provide information on the stability and stiffness of materials. In the present study author investigated relation between elastic constant and temperature in Borassus Flabellifier 'BF' wood part. Determination of elastic properties of material is based on the longitudinal wave's velocities via ultrasonic methods. The resonant frequencies of the specimens were measured by Ultrasonic Interferometer (for solids) dual frequency using longitudinal cubic piezoelectric crystal of quartz of frequency 123.62 KHz. The temperature variations from room temperature were done by PID control unit, Mittal Enterprises, New Delhi, India. Characterization of the samples was done by scanning electron microscope (SEM) Model JEOL JSM5400 at 5.0kvx750, 10 μm.

  6. Wood as inspiration for new stimuli-responsive structures and materials

    Science.gov (United States)

    Joseph E. Jakes; Nayomi Plaza-Rodriguez; Samuel L. Zelinka; Donald S. Stone; Sophie-Charlotte Gleber; Stefan Vogt

    2014-01-01

    Nature has often provided inspiration for new smart structures and materials. Recently, we showed a bundle of a few wood cells are moisture-activated torsional actuators that can reversibly twist multiple revolutions per centimeter of length. The bundles produce specific torque higher than that produced by electric motors and possess shape memory twist capabilities....

  7. Enhanced control of electrochemical response in metallic materials in neural stimulation electrode applications

    Energy Technology Data Exchange (ETDEWEB)

    Watkins, K.G.; Steen, W.M.; Manna, I. [Univ. of Liverpool (United Kingdom)] [and others

    1996-12-31

    New means have been investigated for the production of electrode devices (stimulation electrodes) which could be implanted in the human body in order to control pain, activate paralysed limbs or provide electrode arrays for cochlear implants for the deaf or for the relief of tinitus. To achieve this ion implantation and laser materials processing techniques were employed. Ir was ion implanted in Ti-6Al-4V alloy and the surface subsequently enriched in the noble metal by dissolution in sulphuric acid. For laser materials processing techniques, investigation has been carried out on the laser cladding and laser alloying of Ir in Ti wire. A particular aim has been the determination of conditions required for the formation of a two phase Ir, Ir-rich, and Ti-rich microstructure which would enable subsequent removal of the non-noble phase to leave a highly porous noble metal with large real surface area and hence improved charge carrying capacity compared with conventional non porous electrodes. Evaluation of the materials produced has been carried out using repetitive cyclic voltammetry, amongst other techniques. For laser alloyed Ir on Ti wire, it has been found that differences in the melting point and density of the materials makes control of the cladding or alloying process difficult. Investigation of laser process parameters for the control of alloying and cladding in this system was carried out and a set of conditions for the successful production of two phase Ir-rich and Ti-rich components in a coating layer with strong metallurgical bonding to the Ti alloy substrate was derived. The laser processed material displays excellent potential for further development in providing stimulation electrodes with the current carrying capacity of Ir but in a form which is malleable and hence capable of formation into smaller electrodes with improved spatial resolution compared with presently employed electrodes.

  8. System for Prevention, Detection and Response to Radioactive Materials in Scrap Metal in Ukraine

    Energy Technology Data Exchange (ETDEWEB)

    Makarovska, O., E-mail: makarovska@hq.snrc.gov.ua [State Nuclear Regulatory Committee of Ukraine, Kiev (Ukraine)

    2011-07-15

    The State control system to prevent, detect and respond to cases of radioactive material in scrap metal is functioning in Ukraine. The system includes regulations for the safe and secure management of metal scrap and administrative and technical measures to prevent, detect and respond to cases of radioactive material in scrap metal. The key elements of prevention are the system of licensing and supervision in the sphere of radioactive material use and the State system for inventory, registration and control of radiation sources. Metal scrap management is licensed by the Ministry of Industrial Policy and one of the licence conditions is radiation control of the scrap metal. State supervision of the operations with metal scrap is provided by Ministry of Health and Ministry of Environmental Protection according to the regulation 'State sanitary-ecological standard for metal scrap management'. Specific standards exist for the export of metal scrap. Export consignments are followed by a certificate that proves the radiological safety of the metal. Ukrainian metallurgical plants provide an input radiation control of metal scrap and an output control of the produced metal. Thus, there exists a five barrier system of metal scrap control: border control; exclusion zone perimeter control; metal scrap dealers control; metallurgical plants (input control and output control of produced metal); and export consignments radiological certification. To regain control over orphan sources (including occasional radioactive material in the scrap metal) the 'procedure for interaction of executive authorities and involved legal entities in case of revealing of radiation sources in no legal use' was approved by a Resolution of the Cabinet of Ministers of Ukraine. The investigation of each case with feedback, information of involved bodies, safe and secure storage of restored radioactive material are provided according to this procedure. (author)

  9. Plant growth response in experimental soilless mixes prepared from coal combustion products and organic waste materials

    Energy Technology Data Exchange (ETDEWEB)

    Bardhan, S.; Watson, M.; Dick, W.A. [Ohio State University, Wooster, OH (United States)

    2008-07-15

    Large quantities of organic materials such as animal manures, yard trimmings, and biosolids are produced each year. Beneficial use options for them are often limited, and composting has been proposed as a way to better manage these organic materials. Similarly, burning of coal created 125 million tons of coal combustion products (CCP) in the United States in 2006. An estimated 53 million tons of CCP were reused, whereas the remainder was deposited in landfills. By combining CCP and composted organic materials (COM), we were able to create soilless plant growth mixes with physicochemical conditions that can support excellent plant growth. An additional benefit is the conservation of natural raw materials, such as peat, which is generally used for making soilless mixes. Experimental mixes were formulated by combining CCP and COM at ratios ranging from 2:8 to 8:2 (vol/vol), respectively. Water content at saturation for the created mixes was 63% to 72%, whereas for the commercial control, it was 77%. pH values for the best performing mixes ranged between 5.9 and 6.8. Electrical conductivity and concentrations of required plant nutrient were also within plant growth recommendations for container media. Significantly (P < 0.0001) higher plant biomass growth (7%-130%) was observed in the experimental mixes compared with a commercial mix. No additional fertilizers were provided during the experiment, and reduced fertilization costs can thus accrue as an added benefit to the grower. In summary, combining CCP and COM, derived from source materials often viewed as wastes, can create highly productive plant growth mixes.

  10. Mechanical characterization of materials for dental applications

    International Nuclear Information System (INIS)

    Pajares, A.; Miranda, P.; Guiberteau, F.; Cumbrera, F. I.

    2001-01-01

    An study of the damage induced in dental materials and model multilayer systems by masticatory contact stresses, simulated by hertz ian indentation test, have been performed. In particular, the nature of induced damage has been identified, and quantified from stress-strain curves and critical loads for yielding or crack initiation. For multilayer systems, test have been numerically simulated using finite element techniques (FEM). FEM simulations complement indentation test, allowing to justify the observed fracture modes from calculated stress fields. Practical implications can be derived from our results, relevant to the design of multilayer structures tolerant to contact damage. (Author) 34 refs

  11. On Optimal Shapes in Materials and Structures

    DEFF Research Database (Denmark)

    Pedersen, Pauli

    2000-01-01

    In the micromechanics design of materials, as well as in the design of structural connections, the boundary shape plays an important role. The objective may be the stiffest design, the strongest design or just a design of uniform energy density along the shape. In an energy formulation it is proven...... that these three objectives have the same solution, at least within the limits of geometrical constraints, including the parametrization. Without involving stress/strain fields, the proof holds for 3D-problems, for power-law nonlinear elasticity and for anisotropic elasticity. To clarify the importance...

  12. Role and responsibilities of management in NPP personnel training and competence. Working material

    International Nuclear Information System (INIS)

    1994-01-01

    The main aim and result of this seminar was imparting knowledge to various levels of Paks NPP management on their special tasks and responsibilities to achieve personnel competence, which include: meeting relevant regulatory and other requirements; defining the qualifications for NPP personnel jobs; training using systematic approach to training to attain the required level of qualification and competence of all NPP personnel, which includes management, operations, maintenance and technical support personnel and others; recruiting and retaining qualified personnel, including career development; supporting the training of all personnel on their responsibilities for introducing, maintaining and improving safety. Refs, figs and tabs

  13. Nonlinear response and avalanche behavior in metallic glasses

    Science.gov (United States)

    Riechers, B.; Samwer, K.

    2017-08-01

    The response to different stress amplitudes at temperatures below the glass transition temperature is analyzed by mechanical oscillatory excitation of Pd40Ni40P20 metallic glass samples in single cantilever bending geometry. While low amplitude oscillatory excitations are commonly used in mechanical spectroscopy to probe the relaxation spectrum, in this work the response to comparably high amplitudes is investigated. The strain response of the material is well below the critical yield stress even for highest stress amplitudes, implying the expectation of a linear relation between stress and strain according to Hooke's Law. However, a deviation from the linear behavior is evident, which is analyzed in terms of temperature dependence and influence of the applied stress amplitude by two different approaches of evaluation. The nonlinear approach is based on a nonlinear expansion of the stress-strain-relation, assuming an intrinsic nonlinear character of the shear or elastic modulus. The degree of nonlinearity is extracted by a period-by-period Fourier-analysis and connected to nonlinear coefficients, describing the intensity of nonlinearity at the fundamental and higher harmonic frequencies. The characteristic timescale to adapt to a significant change in stress amplitude in terms of a recovery timescale to a steady state value is connected to the structural relaxation time of the material, suggesting a connection between the observed nonlinearity and primary relaxation processes. The second approach of evaluation is termed the incremental analysis and relates the observed response behavior to avalanches, which occur due to the activation and correlation of local microstructural rearrangements. These rearrangements are connected with shear transformation zones and correspond to localized plastic events, which are superimposed on the linear response behavior of the material.

  14. A Coupled Damage and Reaction Model for Simulating Energetic Material Response to Impact Hazards

    International Nuclear Information System (INIS)

    BAER, MELVIN R.; DRUMHELLER, D.S.; MATHESON, E.R.

    1999-01-01

    The Baer-Nunziato multiphase reactive theory for a granulated bed of energetic material is extended to allow for dynamic damage processes, that generate new surfaces as well as porosity. The Second Law of Thermodynamics is employed to constrain the constitutive forms of the mass, momentum, and energy exchange functions as well as those for the mechanical damage model ensuring that the models will be dissipative. The focus here is on the constitutive forms of the exchange functions. The mechanical constitutive modeling is discussed in a companion paper. The mechanical damage model provides dynamic surface area and porosity information needed by the exchange functions to compute combustion rates and interphase momentum and energy exchange rates. The models are implemented in the CTH shock physics code and used to simulate delayed detonations due to impacts in a bed of granulated energetic material and an undamaged cylindrical sample

  15. Thermal Response Of An Aerated Concrete Wall With Micro-Encapsulated Phase Change Material

    Science.gov (United States)

    Halúzová, Dušana

    2015-06-01

    For many years Phase Change Materials (PCM) have attracted attention due to their ability to store large amounts of thermal energy. This property makes them a candidate for the use of passive heat storage. In many applications, they are used to avoid the overheating of the temperature of an indoor environment. This paper describes the behavior of phase change materials that are inbuilt in aerated concrete blocks. Two building samples of an aerated concrete wall were measured in laboratory equipment called "twin-boxes". The first box consists of a traditional aerated concrete wall; the second one has additional PCM micro-encapsulated in the wall. The heat flux through the wall was measured and compared to simulation results modeled in the ESP-r program. This experimental measurement provides a foundation for a model that can be used to analyze further building constructions.

  16. Color stability of restorative materials in response to Arabic coffee, Turkish coffee and Nescafe.

    Science.gov (United States)

    Al-Samadani, Khalid H

    2013-07-01

    To evaluate the effect of Arabic coffee, Turkish coffee and Nescafe on the color stability of four different composite resins after a period of aging time 1, 7 and 30 days. Twenty specimens from each type of tested composite resin material were prepared. Five specimens from each tested material (Z350 XT, Artist, GC and Z250) was evaluated after storage in Arabic coffee, Turkish coffee, Nescafe and distil water (control) at 37°C in a dark container for 1, 7 and 30 days. Color measurement was done using colorimeter based on the CIE L* a* b* color scale. Color differences ΔE*ab, Δb* and Δa* among specimens immersed in distil water and staining coffee beverages were evaluated overtime. Mean values were statistically analyzed with one-way analysis of variance (ANOVA), followed by Tukey test with p Nescafe except Δa*. The highest total color difference ΔE*ab after 30 days was in group A Arabic coffee (ΔE > 1.5 perceivable) and not perceivable in group B Turkish coffee and group C Nescafe. For Δb* all materials discolored toward yellowness after 30 days except Arabic coffee group which shifted from yellowness toward blueness (Δb*> 1.5 perceivable). The effect of staining beverages on the resin composite materials increases with time of aging toward yellowness and not perceivable in all groups except with Arabic coffee which had highest effect after 30 days and the discoloration shifted from yellowness to blueness perceivable.

  17. Leptothrix sp sheaths modified with iron oxide particles: Magnetically responsive, high aspect ratio functional material

    Czech Academy of Sciences Publication Activity Database

    Šafařík, Ivo; Angelova, R.; Baldíková, Eva; Pospišková, K.; Šafaříková, Miroslava

    2017-01-01

    Roč. 71, FEB (2017), s. 1342-1346 ISSN 0928-4931 R&D Projects: GA ČR(CZ) GA14-11516S; GA MŠk(CZ) LD14075 Institutional support: RVO:67179843 Keywords : removal * Leptothrix * Magnetic modification * Iron oxide * High aspect ratio material Subject RIV: EI - Biotechnology ; Bionics OBOR OECD: Environmental sciences (social aspects to be 5.7) Impact factor: 4.164, year: 2016

  18. DETERMINATION OF THERMAL RESPONSE OF CARRARA AND SNEZNIKOVSKY MARBLE USED AS A BUILDING MATERIALS

    Directory of Open Access Journals (Sweden)

    Veronika Petráňová

    2016-02-01

    Full Text Available Physical weathering of marble, widely used as a cladding material on buildings, is one of the most common damaging mechanism caused by anisotropic thermal expansion of calcite grains. The extent of marble deterioration depends mainly on stone fabric and texture. Dry cuboids of Carrara marble and marble from Dolni Morava quarry were subjected to microscopic analysis and thermal cycling, to determine the thermal expansion related to stone fabric and predominant lattice orientation of grains (i.e. texture.

  19. DETERMINATION OF THERMAL RESPONSE OF CARRARA AND SNEZNIKOVSKY MARBLE USED AS A BUILDING MATERIALS

    OpenAIRE

    Veronika Petráňová; Jaroslav Valach; Alberto Viani; Marta Peréz Estébanez

    2016-01-01

    Physical weathering of marble, widely used as a cladding material on buildings, is one of the most common damaging mechanism caused by anisotropic thermal expansion of calcite grains. The extent of marble deterioration depends mainly on stone fabric and texture. Dry cuboids of Carrara marble and marble from Dolni Morava quarry were subjected to microscopic analysis and thermal cycling, to determine the thermal expansion related to stone fabric and predominant lattice orientation of grains (i....

  20. Response of Slope Made Up of Soil and Other Waste Materials under Sinusoidal Motion

    OpenAIRE

    Chanda, Nipa; Ghosh, Sima; Pal, Manish

    2017-01-01

    Performance of small scale embankment slopes under dynamic loading is experimentally evaluated in the present work conducting shake table test. Model slopes are made up of soil and soil dust mixtures at various water level conditions. Material dust types as taken in the experiment are saw dust, stone dust, brick dust, and building demolish dust. Shear strength of soil such as cohesion and internal friction angle increases on an average 25% and 23%, respectively, when soil is mixed with 30% bu...

  1. Influence of vibrational treatment on thermomechanical response of material under conditions identical to friction stir welding

    Energy Technology Data Exchange (ETDEWEB)

    Konovalenko, Ivan S., E-mail: ivkon@ispms.tsc.ru [Institute of Strength Physics and Materials Science SB RAS, Tomsk, 634055 (Russian Federation); Konovalenko, Igor S., E-mail: igkon@ispms.tsc.ru; Kolubaev, Evgeniy A., E-mail: eak@ispms.tsc.ru [Institute of Strength Physics and Materials Science SB RAS, Tomsk, 634055 (Russian Federation); National Research Tomsk Polytechnic University, Tomsk, 634050 (Russian Federation); Dmitriev, Andrey I., E-mail: dmitr@ispms.tsc.ru [Institute of Strength Physics and Materials Science SB RAS, Tomsk, 634055 (Russian Federation); National Research Tomsk Polytechnic University, Tomsk, 634050 (Russian Federation); National Research Tomsk State University, Tomsk, 634050 (Russian Federation); Psakhie, Sergey G., E-mail: sp@ms.tsc.ru [Institute of Strength Physics and Materials Science SB RAS, Tomsk, 634055 (Russian Federation); National Research Tomsk State University, Tomsk, 634050 (Russian Federation)

    2015-10-27

    A molecular dynamics model was constructed to describe material loading on the atomic scale by the mode identical to friction stir welding. It was shown that additional vibration applied to the tool during the loading mode provides specified intensity values and continuous thermomechanical action during welding. An increase in additional vibration intensity causes an increase both in the force acting on the workpiece from the rotating tool and in temperature within the welded area.

  2. Cellular Responses in Human Dental Pulp Stem Cells Treated with Three Endodontic Materials

    Directory of Open Access Journals (Sweden)

    Alejandro Victoria-Escandell

    2017-01-01

    Full Text Available Human dental pulp stem cells (HDPSCs are of special relevance in future regenerative dental therapies. Characterizing cytotoxicity and genotoxicity produced by endodontic materials is required to evaluate the potential for regeneration of injured tissues in future strategies combining regenerative and root canal therapies. This study explores the cytotoxicity and genotoxicity mediated by oxidative stress of three endodontic materials that are widely used on HDPSCs: a mineral trioxide aggregate (MTA-Angelus white, an epoxy resin sealant (AH-Plus cement, and an MTA-based cement sealer (MTA-Fillapex. Cell viability and cell death rate were assessed by flow cytometry. Oxidative stress was measured by OxyBlot. Levels of antioxidant enzymes were evaluated by Western blot. Genotoxicity was studied by quantifying the expression levels of DNA damage sensors such as ATM and RAD53 genes and DNA damage repair sensors such as RAD51 and PARP-1. Results indicate that AH-Plus increased apoptosis, oxidative stress, and genotoxicity markers in HDPSCs. MTA-Fillapex was the most cytotoxic oxidative stress inductor and genotoxic material for HDPSCs at longer times in preincubated cell culture medium, and MTA-Angelus was less cytotoxic and genotoxic than AH-Plus and MTA-Fillapex at all times assayed.

  3. Structural code benchmarking for the analysis of impact response of nuclear material shipping casks

    International Nuclear Information System (INIS)

    Glass, R.E.

    1984-01-01

    The Transportation Technology Center at Sandia National Laboratories has initiated a program to benchmark thermal and structural codes that are available to the nuclear material transportation community. The program consists of the following five phrases: (1) code inventory and review, (2) development of a cask-like set of problems, (3) multiple independent numerical analyses of the problems, (4) transfer of information, and (5) performance of experiments to obtain data for comparison with the numerical analyses. This paper will summarize the results obtained by the independent numerical analyses. The analyses indicate the variability that can be expected both due to differences in user-controlled parameters and from code-to-code differences. The results show that in purely elastic analyses, differences can be attributed to user controlled parameters. Model problems involving elastic/plastic material behavior and large deformations, however, have greater variability with significant differences reported for implicit and explicit integration schemes in finite element programs. This variability demonstrates the need to obtain experimental data to properly benchmark codes utilizing elastic/plastic material models and large deformation capability

  4. Amplification of the Luminescence Response in Organic Materials Exposed to Ionizing Radiation

    International Nuclear Information System (INIS)

    Michel, M.; Rocha, L.; Hamel, M.; Normand, S.

    2013-06-01

    Polymer-based scintillators present interesting features for the field of ionizing radiation detection, related to the high sensitivity of fluorescence techniques coupled to the manufacturing advantages of such materials. Organic materials can indeed be manufactured into large sensing areas with different geometrical conformations through low-cost fabrication techniques. While results herein presented focus on liquids, the same phenomena would occur in solid samples. Widely used for sensing applications because of its high sensitivity, fluorescence has yet been further improved using technologies yielded by research in photonics. It has already been shown that the use of nano-structuring for sensing applications enables previously unattained sensitivities. Herein we propose a technique based on the manipulation of light using nano-structuring of the detection medium in order to enable the amplification of the sensitive material emission. This amplification of the luminescence signal is aimed at reducing the detection limit of low-energy beta emitters such as tritium, well-known issue of major importance. The first step of our study, presented here, consists in demonstrating the ability of well-known scintillators to emit in laser regime when optically excited in a Distributed Feedback scheme. They are, to our knowledge, the first of their kind. The technique here presented, being usable whatever the sample maximum emission wavelength, should also enable a simplification of the devices based on scintillators. (authors)

  5. Stakeholders’ responses to CSR tradeoffs : SWhen other-orientation and trust trump material self-interest

    NARCIS (Netherlands)

    Bridoux, F.; Stofberg, N.; den Hartog, D.

    2016-01-01

    When investing in corporate social responsibility (CSR), managers may strive for a win-win scenario where all stakeholders end up better off, but they may not always be able to avoid trading off stakeholders' interests. To provide guidance to managers who have to make tradeoffs, this study used a

  6. AEROS: a real-time emergency response system for atmospheric releases of toxic material

    International Nuclear Information System (INIS)

    Nasstrom, J.S.; Greenly, G.D.

    1986-01-01

    The Atmospheric Release Advisory Capability (ARAC) at the Lawrence Livermore National Laboratory has developed a sophisticated computer-based real-time emergency response system for radiotoxic releases into the atmosphere. The ARAC Emergency Response Operating System (AEROS) has a centralized computer facility linked to remote site computers, meteorological towers, and meteorological data sources. The system supports certain fixed sites, but has the ability to respond to accidents at arbitrary locations. Product quality and response time are optimized by using complex three-dimensional dispersion models; extensive on-line data bases; automated data processing; and an efficient user interface, employing graphical computer displays and computer-displayed forms. Upon notification, the system automatically initiates a response to an emergency and proceeds through preliminary calculations, automatically processing accident information, meteorological data, and model parameters. The model calculations incorporate mass-consistent three-dimensional wind fields, terrain effects, and particle-in-cell diffusion. Model products are color images of dose or deposition contours overlaid on a base map

  7. Liquid crystal alignment in electro-responsive nanostructured thermosetting materials based on block copolymer dispersed liquid crystal

    Energy Technology Data Exchange (ETDEWEB)

    Tercjak, A; Garcia, I; Mondragon, I [Materials-Technologies Group, Departamento IngenierIa Quimica y M Ambiente, Escuela Politecnica, Universidad PaIs Vasco/Euskal Herriko Unibertsitatea, Plaza Europa 1, E-20018 Donostia-San Sebastian (Spain)], E-mail: scptesza@sc.ehu.es, E-mail: inaki.mondragon@ehu.es

    2008-07-09

    Novel well-defined nanostructured thermosetting systems were prepared by modification of a diglicydylether of bisphenol-A epoxy resin (DGEBA) with 10 or 15 wt% amphiphilic poly(styrene-b-ethylene oxide) block copolymer (PSEO) and 30 or 40 wt% low molecular weight liquid crystal 4'-(hexyl)-4-biphenyl-carbonitrile (HBC) using m-xylylenediamine (MXDA) as a curing agent. The competition between well-defined nanostructured materials and the ability for alignment of the liquid crystal phase in the materials obtained has been studied by atomic and electrostatic force microscopy, AFM and EFM, respectively. Based on our knowledge, this is the first time that addition of an adequate amount (10 wt%) of a block copolymer to 40 wt% HBC-(DGEBA/MXDA) leads to a well-organized nanostructured thermosetting system (between a hexagonal and worm-like ordered structure), which is also electro-responsive with high rate contrast. This behavior was confirmed using electrostatic force microscopy (EFM), by means of the response of the HBC liquid crystal phase to the voltage applied to the EFM tip. In contrast, though materials containing 15 wt% PSEO and 30 wt% HBC also form a well-defined nanostructured thermosetting system, they do not show such a high contrast between the uncharged and charged surface.

  8. Liquid crystal alignment in electro-responsive nanostructured thermosetting materials based on block copolymer dispersed liquid crystal.

    Science.gov (United States)

    Tercjak, A; Garcia, I; Mondragon, I

    2008-07-09

    Novel well-defined nanostructured thermosetting systems were prepared by modification of a diglicydylether of bisphenol-A epoxy resin (DGEBA) with 10 or 15 wt% amphiphilic poly(styrene-b-ethylene oxide) block copolymer (PSEO) and 30 or 40 wt% low molecular weight liquid crystal 4'-(hexyl)-4-biphenyl-carbonitrile (HBC) using m-xylylenediamine (MXDA) as a curing agent. The competition between well-defined nanostructured materials and the ability for alignment of the liquid crystal phase in the materials obtained has been studied by atomic and electrostatic force microscopy, AFM and EFM, respectively. Based on our knowledge, this is the first time that addition of an adequate amount (10 wt%) of a block copolymer to 40 wt% HBC-(DGEBA/MXDA) leads to a well-organized nanostructured thermosetting system (between a hexagonal and worm-like ordered structure), which is also electro-responsive with high rate contrast. This behavior was confirmed using electrostatic force microscopy (EFM), by means of the response of the HBC liquid crystal phase to the voltage applied to the EFM tip. In contrast, though materials containing 15 wt% PSEO and 30 wt% HBC also form a well-defined nanostructured thermosetting system, they do not show such a high contrast between the uncharged and charged surface.

  9. Liquid crystal alignment in electro-responsive nanostructured thermosetting materials based on block copolymer dispersed liquid crystal

    International Nuclear Information System (INIS)

    Tercjak, A; Garcia, I; Mondragon, I

    2008-01-01

    Novel well-defined nanostructured thermosetting systems were prepared by modification of a diglicydylether of bisphenol-A epoxy resin (DGEBA) with 10 or 15 wt% amphiphilic poly(styrene-b-ethylene oxide) block copolymer (PSEO) and 30 or 40 wt% low molecular weight liquid crystal 4'-(hexyl)-4-biphenyl-carbonitrile (HBC) using m-xylylenediamine (MXDA) as a curing agent. The competition between well-defined nanostructured materials and the ability for alignment of the liquid crystal phase in the materials obtained has been studied by atomic and electrostatic force microscopy, AFM and EFM, respectively. Based on our knowledge, this is the first time that addition of an adequate amount (10 wt%) of a block copolymer to 40 wt% HBC-(DGEBA/MXDA) leads to a well-organized nanostructured thermosetting system (between a hexagonal and worm-like ordered structure), which is also electro-responsive with high rate contrast. This behavior was confirmed using electrostatic force microscopy (EFM), by means of the response of the HBC liquid crystal phase to the voltage applied to the EFM tip. In contrast, though materials containing 15 wt% PSEO and 30 wt% HBC also form a well-defined nanostructured thermosetting system, they do not show such a high contrast between the uncharged and charged surface

  10. The effect of build-up cap materials on the response of an ionization chamber to 60Co gamma rays

    International Nuclear Information System (INIS)

    Rocha, M.P.O.; Almeida, C.E. de

    1993-01-01

    Knowledge of the effect of wall and build-up cap materials on ionization chamber response is necessary to determine absorbed dose in a medium using a calibration factor based on exposure or kerma in air. Attenuation and scattering effects of 60 Co gamma rays in the ionization chamber wall and build-up cap, as well as their non-equivalence to air, were studied with an OFS ionization chamber (Delrin wall) and a set of build-up caps specially built for this purpose. Results for a specific material were plotted as functions of wall and cap total thickness, extrapolated to zero wall thickness, then corrected for mean centre of electron production in the wall (= 0.136 g cm -2 ). Correction factors for a specific thickness were analysed in relation to cap material, and to relative responses compared with values calculated by using AAPM, SEFM and IAEA formalisms for cap effects. A Monte Carlo calculation was performed to compare the experimental and theoretical values. Calculations showed an agreement within 0.1% with experimental values and a wall effect of approximately 1.6%. (Author)

  11. Effect of initial strain and material nonlinearity on the nonlinear static and dynamic response of graphene sheets

    Science.gov (United States)

    Singh, Sandeep; Patel, B. P.

    2018-06-01

    Computationally efficient multiscale modelling based on Cauchy-Born rule in conjunction with finite element method is employed to study static and dynamic characteristics of graphene sheets, with/without considering initial strain, involving Green-Lagrange geometric and material nonlinearities. The strain energy density function at continuum level is established by coupling the deformation at continuum level to that at atomic level through Cauchy-Born rule. The atomic interactions between carbon atoms are modelled through Tersoff-Brenner potential. The governing equation of motion obtained using Hamilton's principle is solved through standard Newton-Raphson method for nonlinear static response and Newmark's time integration technique to obtain nonlinear transient response characteristics. Effect of initial strain on the linear free vibration frequencies, nonlinear static and dynamic response characteristics is investigated in detail. The present multiscale modelling based results are found to be in good agreement with those obtained through molecular mechanics simulation. Two different types of boundary constraints generally used in MM simulation are explored in detail and few interesting findings are brought out. The effect of initial strain is found to be greater in linear response when compared to that in nonlinear response.

  12. Influence of Clay Content, Mineralogy and Fabric On Radar Frequency Response of Aquifer Materials

    Science.gov (United States)

    West, L. J.; Handley, K.

    High frequency electromagnetic methods such as ground penetrating radar (GPR) and time domain reflectometry (TDR) are widely employed to measure water saturation in the vadose zone and water filled porosity in the saturated zone. However, previous work has shown that radar frequency dielectric properties are strongly influenced by clay as well as by water content. They have also shown that that the dielectric response of clay minerals is strongly frequency dependent, and that even a small proportion of clay such as that present in many sandstone aquifers can have a large effect at typi- cal GPR frequencies (around 100MHz). Hence accurate water content/porosity deter- mination requires clay type and content to be taken into account. Reported here are dielectric measurements on clay-sand mixtures, aimed at investigating the influence of clay mineralogy, particle shape, and the geometrical arrangement of the mixture constituents on GPR and TDR response. Dielectric permittivity (at 50-1000MHz) was measured for mixtures of Ottawa Sand and various clay minerals or clay size quartz rock flour, using a specially constructed dielectric cell. Both homogeneous and layered mixtures were tested. The influence of pore water salinity, clay type, and particle arrangement on the dielectric response is interpreted in terms of dielectric dispersion mechanisms. The appropriateness of var- ious dielectric mixing rules such as the Complex Refractive Index Method (CRIM) for determination of water content or porosity from field GPR and TDR data are dis- cussed.

  13. In vitro mesenchymal stem cell response to a CO{sub 2} laser modified polymeric material

    Energy Technology Data Exchange (ETDEWEB)

    Waugh, D.G., E-mail: d.waugh@chester.ac.uk [Laser Engineering and Manufacturing Research Centre, Faculty of Science and Engineering, University of Chester, Chester CH1 4BJ (United Kingdom); Hussain, I. [School of Life Sciences, Brayford Pool, University of Lincoln, Lincoln LN6 7TS (United Kingdom); Lawrence, J.; Smith, G.C. [Laser Engineering and Manufacturing Research Centre, Faculty of Science and Engineering, University of Chester, Chester CH1 4BJ (United Kingdom); Cosgrove, D. [School of Life Sciences, Brayford Pool, University of Lincoln, Lincoln LN6 7TS (United Kingdom); Toccaceli, C. [Laser Engineering and Manufacturing Research Centre, Faculty of Science and Engineering, University of Chester, Chester CH1 4BJ (United Kingdom)

    2016-10-01

    With an ageing world population it is becoming significantly apparent that there is a need to produce implants and platforms to manipulate stem cell growth on a pharmaceutical scale. This is needed to meet the socio-economic demands of many countries worldwide. This paper details one of the first ever studies in to the manipulation of stem cell growth on CO{sub 2} laser surface treated nylon 6,6 highlighting its potential as an inexpensive platform to manipulate stem cell growth on a pharmaceutical scale. Through CO{sub 2} laser surface treatment discrete changes to the surfaces were made. That is, the surface roughness of the nylon 6,6 was increased by up to 4.3 μm, the contact angle was modulated by up to 5° and the surface oxygen content increased by up to 1 atom %. Following mesenchymal stem cell growth on the laser treated samples, it was identified that CO{sub 2} laser surface treatment gave rise to an enhanced response with an increase in viable cell count of up to 60,000 cells/ml when compared to the as-received sample. The effect of surface parameters modified by the CO{sub 2} laser surface treatment on the mesenchymal stem cell response is also discussed along with potential trends that could be identified to govern the mesenchymal stem cell response.

  14. Triaxial behaviour of a micro-concrete complete stress-strain curves for confining pressures ranging from 0 to 100 MPa

    International Nuclear Information System (INIS)

    Jamet, P.; Millard, A.; Nahas, G.

    1984-05-01

    A series of triaxial tests has been performed on micro-concrete cylinders. The specimens have been strained with a constant displacement rate, up to a deformation of about 10%. Two different domains were distinguihed. For low confining pressures strain softening is observed, the behaviour of the material becomes ductile for high confining pressures. Continuous measurement of the volume of fluid which had to be injected or withdrawn from the cell, to keep the confining pressure constant during the test, allowed to obtain data, concerning the overall lateral deformations of the specimens. Some specimens were also subjected to successive loadings with different confining pressures, in order to study the influence of stress path

  15. Calculation of HPGe Detector Response for NRF Photons Scattered from Threat Materials

    International Nuclear Information System (INIS)

    Park, B. G.; Choi, H. D.

    2009-01-01

    Nuclear Resonance Fluorescence (NRF) is a process of resonant nuclear absorption of photons, followed by deexcitation with emission of fluorescence photons. The cross section of NRF photons process is given by σ i max ≡ 2π(λ/2π) 2 2J+1/2J 0 +1 Γ 0 Γ i /Γ tot 2 , where λ is the wavelength of the photon, J 0 and J are the nuclear spins of the ground state and excited state, respectively, Γ 0 , Γ i and Γ tot are decay width for deexcitation to the ground state, to the i-th mode state and total decay width, respectively. NRF based security inspection technique uses the signatures of resonance energies of the fluorescence photon scattered from nuclides of the illicit materials in cargo container. NRF can be used to identify the material type, quantity and location. It is performed by measuring the fluorescence photon and the transmitted photon spectrum while irradiating Bremsstrahlung photon beam to the sample

  16. Response of inorganic materials to laser - plasma EUV radiation focused with a lobster eye collector

    Science.gov (United States)

    Bartnik, Andrzej; Fiedorowicz, Henryk; Jarocki, Roman; Kostecki, Jerzy; Szczurek, Miroslaw; Havlikova, Radka; Pína, Ladislav; Švéda, Libor; Inneman, Adolf

    2007-05-01

    A single photon of EUV radiation carries enough energy to break any chemical bond or excite electrons from inner atomic shells. It means that the radiation regardless of its intensity can modify chemical structure of molecules. It is the reason that the radiation even with low intensity can cause fragmentation of long chains of organic materials and desorption of small parts from their surface. In this work interaction of EUV radiation with inorganic materials was investigated. Different inorganic samples were irradiated with a 10 Hz laser - plasma EUV source based on a gas puff target. The radiation was focused on a sample surface using a lobster eye collector. Radiation fluence at the surface reached 30 mJ/cm2 within a wavelength range 7 - 20 nm. In most cases there was no surface damage even after several minutes of irradiation. In some cases there could be noticed discolouration of an irradiated surface or evidences of thermal effects. In most cases however luminescent and scattered radiation was observed. The luminescent radiation was emitted in different wavelength ranges. It was recorded in a visible range of radiation and also in a wide wavelength range including UV, VUV and EUV. The radiation was especially intense in a case of non-metallic chemical compounds.

  17. Limit analysis of narrow support elements in W7-X considering the serration effect of the stress-strain relation at 4 K

    International Nuclear Information System (INIS)

    Briani, E.; Gianini, C.; Lucca, F.; Marin, A.; Fellinger, J.; Bykov, V.

    2011-01-01

    The magnet support system of the Wendelstein 7-X (W7-X) fusion stellarator includes challenging components, called Narrow Support Elements (NSEs), placed between the Non Planar Coils (NPCs) at the inboard side and aimed at reducing deformation of the coils. NSEs are small contact elements, with special coating to reduce friction, that have to withstand high compressive and shear forces. The objective of this article is to demonstrate the structural reliability of the NSEs under electromagnetic loading (EML), taking into account in a conservative way the relevant material properties at cryogenic temperatures. To this purpose, an appropriate parametric local Finite Element (FE) model of one highly loaded NSE with its components (pad, pad frame and counter pad) and of a portion of the coils has been developed with ABAQUS code and isotropic elastic-plastic material model with hardening/softening has been used, in order to include the serration effect at 4 K. Different mechanical limit analyses have been performed including consecutive steps of shrink fitting the NSEs in the coils, cooling down to 4 K and gradual increasing of the coil displacements induced by the EML.

  18. Limit analysis of narrow support elements in W7-X considering the serration effect of the stress-strain relation at 4 K

    Energy Technology Data Exchange (ETDEWEB)

    Briani, E., E-mail: erica.briani@ltcalcoli.it [L.T.Calcoli SaS, Piazza Prinetti 26/B, 23807, Merate (Saint Lucia) (Italy); Gianini, C.; Lucca, F.; Marin, A. [L.T.Calcoli SaS, Piazza Prinetti 26/B, 23807, Merate (Saint Lucia) (Italy); Fellinger, J.; Bykov, V. [MPI fur Plasmaphysik (IPP) Wendelsteinstrasse I, D-17491 Greifswald (Germany)

    2011-10-15

    The magnet support system of the Wendelstein 7-X (W7-X) fusion stellarator includes challenging components, called Narrow Support Elements (NSEs), placed between the Non Planar Coils (NPCs) at the inboard side and aimed at reducing deformation of the coils. NSEs are small contact elements, with special coating to reduce friction, that have to withstand high compressive and shear forces. The objective of this article is to demonstrate the structural reliability of the NSEs under electromagnetic loading (EML), taking into account in a conservative way the relevant material properties at cryogenic temperatures. To this purpose, an appropriate parametric local Finite Element (FE) model of one highly loaded NSE with its components (pad, pad frame and counter pad) and of a portion of the coils has been developed with ABAQUS code and isotropic elastic-plastic material model with hardening/softening has been used, in order to include the serration effect at 4 K. Different mechanical limit analyses have been performed including consecutive steps of shrink fitting the NSEs in the coils, cooling down to 4 K and gradual increasing of the coil displacements induced by the EML.

  19. Control of unauthorized transportation of nuclear and radioactive materials across state territories and borders: detection, response and decision support

    International Nuclear Information System (INIS)

    Stavrov, Andrei; Frymire, Allan; Kagan, Leonid; Karczewski, Jerzy

    2008-01-01

    A new solution to control the illicit transportation of nuclear and radioactive materials is proposed and described. This solution consists in the creation of a system of gamma and gamma-neutron radiation monitors and fundamentally new software/hardware package RAVEN (Radiation Alarm and Video Event Notification) which integrates different type monitors in a single network. The main purpose of this system is to analyze and store data coming from radiation monitors, to process these data and to help the user to interpret them. This ensures the user's correct response to all the alarms triggered by radiation monitors and indicating the presence of radioactive and/or nuclear materials in scanned objects. The developed system can integrate fixed radiation monitors that can be installed in different sites within not only one country but in different sites worldwide in a single network. The system can be adapted to the local conditions and allows the user: (i) To detect minimum quantities of special nuclear and radioactive materials (specified by the national and international requirements) by their gamma and/or neutron radiation; (ii) To acquire, store and analyze digital data and video images related to cargos with radioactive materials crossing a state border or an object limits; (iii) To make these data accessible to users at different levels ensuring effective operation of both central alarm stations (state, regional or agency center) and local alarm stations (border cross points or object limits). (author)

  20. Sources of ionizing radiation, radioactive or nuclear materials out of control. National system of response in Slovakia

    International Nuclear Information System (INIS)

    Auxtova, L.; Adamek, P.; Moravecb, R.; Melich, M.

    2003-01-01

    In this paper authors deals with the Customs inspection of radioactive materials - present situation as well as with situation after accession of the Slovak Republic process to European Union (EU). he actual response system to incidents with orphan sources or radioactive material occurring in metal scrap, illicit trafficking and disused sources out of control is laid down on the following scheme. The national strategy is aimed to establish a more effective responding system preventing further illegal trafficking with regard to the acceding process which will require for new member states joining EU proper arrangements in improving the safety of radiation sources over the life-cycle to ensure the effective functioning in the conditions of the Slovak Republic's membership in the European Union

  1. Size- and shape-dependent foreign body immune response to materials implanted in rodents and non-human primates

    Science.gov (United States)

    Veiseh, Omid; Doloff, Joshua C.; Ma, Minglin; Vegas, Arturo J.; Tam, Hok Hei; Bader, Andrew R.; Li, Jie; Langan, Erin; Wyckoff, Jeffrey; Loo, Whitney S.; Jhunjhunwala, Siddharth; Chiu, Alan; Siebert, Sean; Tang, Katherine; Hollister-Lock, Jennifer; Aresta-Dasilva, Stephanie; Bochenek, Matthew; Mendoza-Elias, Joshua; Wang, Yong; Qi, Merigeng; Lavin, Danya M.; Chen, Michael; Dholakia, Nimit; Thakrar, Raj; Lacík, Igor; Weir, Gordon C.; Oberholzer, Jose; Greiner, Dale L.; Langer, Robert; Anderson, Daniel G.

    2015-06-01

    The efficacy of implanted biomedical devices is often compromised by host recognition and subsequent foreign body responses. Here, we demonstrate the role of the geometry of implanted materials on their biocompatibility in vivo. In rodent and non-human primate animal models, implanted spheres 1.5 mm and above in diameter across a broad spectrum of materials, including hydrogels, ceramics, metals and plastics, significantly abrogated foreign body reactions and fibrosis when compared with smaller spheres. We also show that for encapsulated rat pancreatic islet cells transplanted into streptozotocin-treated diabetic C57BL/6 mice, islets prepared in 1.5-mm alginate capsules were able to restore blood-glucose control for up to 180 days, a period more than five times longer than for transplanted grafts encapsulated within conventionally sized 0.5-mm alginate capsules. Our findings suggest that the in vivo biocompatibility of biomedical devices can be significantly improved simply by tuning their spherical dimensions.

  2. Supplementary Material for: Astrocyte-specific overexpressed gene signatures in response to methamphetamine exposure in vitro

    KAUST Repository

    Bortell, Nikki; Basova, Liana; Semenova, Svetlana; Fox, Howard; Ravasi, Timothy; Marcondes, Maria

    2017-01-01

    Abstract Background Astrocyte activation is one of the earliest findings in the brain of methamphetamine (Meth) abusers. Our goal in this study was to identify the characteristics of the astrocytic acute response to the drug, which may be critical in pathogenic outcomes secondary to the use. Methods We developed an integrated analysis of gene expression data to study the acute gene changes caused by the direct exposure to Meth treatment of astrocytes in vitro, and to better understand how astrocytes respond, what are the early molecular markers associated with this response. We examined the literature in search of similar changes in gene signatures that are found in central nervous system disorders. Results We identified overexpressed gene networks represented by genes of an inflammatory and immune nature and that are implicated in neuroactive ligand-receptor interactions. The overexpressed networks are linked to molecules that were highly upregulated in astrocytes by all doses of methamphetamine tested and that could play a role in the central nervous system. The strongest overexpressed signatures were the upregulation of MAP2K5, GPR65, and CXCL5, and the gene networks individually associated with these molecules. Pathway analysis revealed that these networks are involved both in neuroprotection and in neuropathology. We have validated several targets associated to these genes. Conclusions Gene signatures for the astrocytic response to Meth were identified among the upregulated gene pool, using an in vitro system. The identified markers may participate in dysfunctions of the central nervous system but could also provide acute protection to the drug exposure. Further in vivo studies are necessary to establish the role of these gene networks in drug abuse pathogenesis.

  3. Synthesis of environmentally responsive organic materials by application of ion track holes in polymer films

    Energy Technology Data Exchange (ETDEWEB)

    Omichi, Hideki; Yoshida, Masaru; Asano, Masaharu [Japan Atomic Energy Research Inst., Takasaki, Gunma (Japan). Takasaki Radiation Chemistry Research Establishment; Katakai, Ryoichi; Spohr, R; Vetter, J

    1997-03-01

    Polymer films were irradiated by heavy ion beams and etched by a concentrated alkali solution to produce particle track membranes (PTMs). Then the PTMs were chemically modified by grafting such monomers as amino acid group containing methacryloyl and N-isopropylacrylamide the polymers of which are known as environmentally responsive hydrogels. The size of pores of the modified PTMs under different temperatures in water was followed by electron microscopy. The pore was controlled from an open state to a completely closed state by changing temperature. The conductivity through the membrane was measured by changing the temperature of the cell. (author)

  4. Naphthalene based AIE active stimuli-responsive material as rewritable media for temporary communication

    Science.gov (United States)

    Pannipara, Mehboobali; Al-Sehemi, Abdullah G.; Kalam, Abul; Asiri, Abdullah M.

    2017-10-01

    Organic molecules having extended π-conjugated moieties is useful for creating 'dynamic' functional materials by modulating the photophysical properties and molecular packing through non-covalent interactions. Herein, we report the photoluminescence properties of a luminogen, NBA, exhibiting aggregation-induced emission (AIE) characteristics, synthesized by Knoevenagel condensation reaction between 2-Hydroxy naphthaldehyde and malononitrile. NBA emits strongly upon aggregation and in solid state with large Stokes shift whereas it is non emissive in pure solvents. The aggregation induced emission behavior of the compound was carried out in DMSO (good solvent)-water mixture (poor solvent) with water fraction (fw) ranging from 0% to 98%. The AIE property of the luminogen were further exploited for fabricating rewritable fluorescent paper substrates that found applications in security printing and data storage where the written images or letters stored on the filter paper are invisible under normal light.

  5. Physical response of backfill materials to mineralogical changes in a basalt environment

    International Nuclear Information System (INIS)

    Couture, R.A.; Seitz, M.G.

    1983-01-01

    Backfill materials surrounding waste canisters in a high-level nuclear waste repository are capable of ensuring very slow flow of groundwater past the canisters, and thereby increase the safety of the repository. However, in the design of a repository it will be necessary to allow for possible changes in the backfill. In this experimental program, changes in permeability, swelling behavior, and plastic behavior of the backfill at the temperatures, pressures, and radiation levels expected in a repository are investigated. The emphasis is on investigation of relevant phenomena and evaluation of experimental procedures for use in licensing procedures. The permeability of a slightly compacted sand-clay mixture containing 25% bentonite, with a dry bulk density of 1.59 g/cm 3 , was determined to be 0.9 x 10 -18 m 2 in liquid water at 25 and 200 0 C, respectively. This is sufficiently low to demonstrate the potential effectiveness of proposed materials. In practice, fractures in the host rock may form short circuits around the backfill, so an even lower flow rate is probable. However, alteration by any of several mechanisms is expected to change the properties of the backfill. Crushed basalt plus bentonite is a leading candidate backfill for a basalt repository. Experiments show that basalt reacts with groundwater vapor or with liquid groundwater producing smectites, zeolites, silica, and other products that may be either beneficial or detrimental to the long-term performance of the backfill. Concentration of groundwater salts in the backfill by evaporation would cause immediate, but possibly reversible, reduction of the swelling abaility of bentonite. Moreover, under some circumstances, gamma radiolysis of moist air in the backfill could produce up to 0.5 mole of nitric acid or ammonia per liter of pore space. 27 references, 7 figures, 4 tables

  6. ROCKING. A computer program for seismic response analysis of radioactive materials transport AND/OR storage casks

    International Nuclear Information System (INIS)

    Ikushima, Takeshi

    1995-11-01

    The computer program ROCKING has been developed for seismic response analysis, which includes rocking and sliding behavior, of radioactive materials transport and/or storage casks. Main features of ROCKING are as follows; (1) Cask is treated as a rigid body. (2) Rocking and sliding behavior are considered. (3) Impact forces are represented by the spring dashpot model located at impact points. (4) Friction force is calculated at interface between a cask and a floor. (5) Forces of wire ropes against tip-over work only as tensile loads. In the paper, the calculation model, the calculation equations, validity calculations and user's manual are shown. (author)

  7. Supplementary Material for: Herboxidiene triggers splicing repression and abiotic stress responses in plants

    KAUST Repository

    Alshareef, Sahar; Ling, Yu; Butt, Haroon; Mariappan, Kiruthiga; Benhamed, Moussa; Mahfouz, Magdy

    2017-01-01

    Abstract Background Constitutive and alternative splicing of pre-mRNAs from multiexonic genes controls the diversity of the proteome; these precisely regulated processes also fine-tune responses to cues related to growth, development, and stresses. Small-molecule inhibitors that perturb splicing provide invaluable tools for use as chemical probes to uncover the molecular underpinnings of splicing regulation and as potential anticancer compounds. Results Here, we show that herboxidiene (GEX1A) inhibits both constitutive and alternative splicing. Moreover, GEX1A activates genome-wide transcriptional patterns involved in abiotic stress responses in plants. GEX1A treatment -activated ABA-inducible promoters, and led to stomatal closure. Interestingly, GEX1A and pladienolide B (PB) elicited similar cellular changes, including alterations in the patterns of transcription and splicing, suggesting that these compounds might target the same spliceosome complex in plant cells. Conclusions Our study establishes GEX1A as a potent splicing inhibitor in plants that can be used to probe the assembly, dynamics, and molecular functions of the spliceosome and to study the interplay between splicing stress and abiotic stresses, as well as having potential biotechnological applications.

  8. The impact of communication materials on public responses to a radiological dispersal device (RDD) attack.

    Science.gov (United States)

    Rogers, M Brooke; Amlôt, Richard; Rubin, G James

    2013-03-01

    It is a common assumption that, in the event of a chemical, biological, radiological, or nuclear (CBRN) attack, a well-prepared and informed public is more likely to follow official recommendations regarding the appropriate safety measures to take. We present findings from a UK study investigating the ability of crisis communication to influence perceptions of risk and behavioral intentions in the general public in response to CBRN terrorism. We conducted a focus group study involving a scenario presented in mock news broadcasts to explore levels of public knowledge, information needs, and intended behavioral reactions to an attack involving an overt radiological dispersal device (RDD), or dirty bomb. We used the findings from these focus groups to design messages for the public that could be presented in a short leaflet. We then tested the effects of the leaflet on reactions to the same scenario in 8 further focus groups. The impact of the new messages on levels of knowledge, information needs, and intended compliance with official recommendations was assessed. The provision of information increased the perceived credibility of official messages and increased reported levels of intended compliance with advice to return to normal/stop sheltering, attend a facility for assessment and treatment, and return to a previously contaminated area after decontamination of the environment has taken place. Should a real attack with an RDD occur, having pretested messages available to address common concerns and information needs should facilitate the public health response to the attack.

  9. Deformation response of Zr after shock-loading

    International Nuclear Information System (INIS)

    Song, S.G.; Gray, G.T. III, and; Lopez, M.F.

    1996-01-01

    The post-shock stress-strain response and microstructural evolution of Zr shock-loaded to 7 GPa were investigated. A Bauschinger effect in the room temperature reload stress-strain behavior due to shock-loading has been observed following yielding. Deformation twinning is shown to play a more important role than slip during post-shock plastic deformation and work hardening. The work hardening rate of the shock-prestrained specimens is less temperature sensitive than that of annealed Zr. The underlying microstructures responsible for the Bauschinger effect and the differences in work hardening behavior are characterized. A new type of dense dislocation arrangement occurring during the shock-wave deformation of Zr is discussed. copyright 1996 American Institute of Physics

  10. Nonequilibrium response of an electron-mediated charge density wave ordered material to a large dc electric field

    Science.gov (United States)

    Matveev, O. P.; Shvaika, A. M.; Devereaux, T. P.; Freericks, J. K.

    2016-01-01

    Using the Kadanoff-Baym-Keldysh formalism, we employ nonequilibrium dynamical mean-field theory to exactly solve for the nonlinear response of an electron-mediated charge-density-wave-ordered material. We examine both the dc current and the order parameter of the conduction electrons as the ordered system is driven by the electric field. Although the formalism we develop applies to all models, for concreteness, we examine the charge-density-wave phase of the Falicov-Kimball model, which displays a number of anomalous behaviors including the appearance of subgap density of states as the temperature increases. These subgap states should have a significant impact on transport properties, particularly the nonlinear response of the system to a large dc electric field.

  11. Quantification of particle-induced inflammatory stress response: a novel approach for toxicity testing of earth materials

    Directory of Open Access Journals (Sweden)

    Harrington Andrea D

    2012-04-01

    Full Text Available Abstract Background Reactive oxygen species (ROS are vital regulators of many cellular functions in the body. The intracellular ROS concentration is highly regulated by a balance between pro-oxidants and anti-oxidants. A chronic excess of pro-oxidants leads to elevated ROS concentrations and inflammation, possibly initiating or enhancing disease onset. Mineral-induced generation of ROS, the role of minerals in upregulating cellular ROS, and their role in the development of several occupational diseases are now widely recognized. However, there is no standard protocol to determine changes in ROS production in cells after exposure to mineral dust or earth materials in general. In this study, a new method for determining the degree of cellular toxicity (i.e., cytotoxicity of particles is described that will help bridge the gap in knowledge. Results By measuring the production of ROS and the viability of cells, an inflammatory stress response (ISR indicator is defined. This approach normalizes the ROS upregulation with respect to the number of viable cells at the time of measurement. We conducted experiments on a series of minerals and soils that represent materials that are inert (i.e., glass beads, anatase, and a soil with low trace element content, moderately reactive (i.e., soil with high trace element content, and highly reactive (i.e., pyrite. Inert materials generated the lowest ISR, averaging 350% compared to the control. Acid washed pyrite produced the highest ISR (1,100 fold higher than the control. The measurements conducted as a function of time showed a complex response. Most materials showed an increase in ISR with particle loading. Conclusions The amount of cellularly generated ROS and cell viability combined provide a better understanding of particle-induced oxidative stress. The results indicate that some earth materials may solicit an initial burst of ROS, followed by a second phase in which cell viability decreases and ROS

  12. Considerations in Emergency Preparedness and Response for a State Embarking on a Nuclear Power Programme, Training Materials

    International Nuclear Information System (INIS)

    2013-01-01

    The aim of these training materials is to provide a practical tool for emergency planning for a State embarking on a nuclear power programme, and to fulfil, in part, functions assigned to the IAEA under the Convention on Assistance in the Case of a Nuclear Accident or Radiological Emergency (the Assistance Convention). Under Article 5.a(ii) of the Assistance Convention, one function of the IAEA is to collect and disseminate to States Parties and Member States information concerning methodologies, techniques and available results of research relating to such emergencies. One of the concerns associated with nuclear power is the possibility that a State embarking on a nuclear power programme might not have sufficient capabilities and therefore would not be adequately prepared to respond to a radiation emergency caused by severe accident conditions. Protecting the public, the environment and property in the event of a failure of any level of defence in depth is the most important safety objective. A robust framework for emergency preparedness and response to a radiation emergency forms the last level of defence in depth and, as such, must be developed and implemented by any State embarking on a nuclear power programme, using best international practices. The establishment of capabilities and arrangements for emergency preparedness and response to severe accident conditions is one of the principal tasks in the development of a national infrastructure for nuclear power. State of the art emergency preparedness and response is a key element in achieving overall plant safety. This training course complements the IAEA publication 'Considerations in Emergency Preparedness and Response for a State Embarking on a Nuclear Power Programme' (EPR-Embarking 2012). These materials are designed to help States apply the guidance in EPR-Embarking 2012, in order to develop the capability to adequately prepare for and respond to a radiation emergency after the commissioning and start of

  13. Effect of skin barrier disruption on immune responses to topically applied cross-reacting material, CRM(197), of diphtheria toxin.

    Science.gov (United States)

    Godefroy, S; Peyre, M; Garcia, N; Muller, S; Sesardic, D; Partidos, C D

    2005-08-01

    The high accessibility of the skin and the presence of immunocompetent cells in the epidermis makes this surface an attractive route for needle-free administration of vaccines. However, the lining of the skin by the stratum corneum is a major obstacle to vaccine delivery. In this study we examined the effect of skin barrier disruption on the immune responses to the cross-reacting material CRM(197), a nontoxic mutant of diphtheria toxin (DTx) that is considered as a vaccine candidate. Application of CRM(197), together with cholera toxin (CT), onto the tape-stripped skin of mice elicited antibody responses that had anti-DTx neutralizing activity. Vaccine delivery onto mildly ablated skin or intact skin did not elicit any detectable anti-CRM(197) antibodies. Mice immunized with CRM(197) alone onto the tape-stripped skin mounted a vigorous antigen-specific proliferative response. In contrast, the induction of cellular immunity after CRM(197) deposition onto mildly ablated or intact skin was adjuvant dependent. Furthermore, epidermal cells were activated and underwent apoptosis that was more pronounced when the stratum corneum was removed by tape stripping. Overall, these findings highlight the potential for transcutaneous delivery of CRM(197) and establish a correlation between the degree of barrier disruption and levels of antigen-specific immune responses. Moreover, these results provide the first evidence that the development of a transcutaneous immunization strategy for diphtheria, based on simple and practical methods to disrupt the skin barrier, is feasible.

  14. Reversible pH Stimulus-Response Material Based on Amphiphilic Block Polymer Self-Assembly and Its Electrochemical Application

    Directory of Open Access Journals (Sweden)

    Tianyi Wang

    2016-06-01

    Full Text Available Stimulus-responsive microporous solid thin films were successfully fabricated by simple molecular self-assembly via an amphiphilic block polymer, polystryene–b–polyacrylic acid (PS–b–PAA. The solid thin films exhibit different surface morphologies in response to external stimuli, such as environments with different pH values in aqueous solutions. The experiments have successfully applied atomic force microscope (AFM technology to observe in-situ surface morphological changes. There is a reversible evolution of the microstructures in buffer solutions over a pH range of 2.4–9.2. These observations have been explained by positing that there is no conventional PAA swelling but that the PAA chains in the micropores stretch and contract with changes in the pH of the solution environment. The hydrophobicity of the solid thin film surface was transformed into super-hydrophilicity, as captured by optical contact angle measurements. The stimulus-responsive dynamics of pore sizes was described by a two-stage mechanism. A promising electrochemical application of this film is suggested via combination with an electrochemical impedance technique. This study is aimed at strategies for the functionalization of stimulus-responsive microporous solid thin films with reversible tunable surface morphologies, and exploring new smart materials with switch-on/switch-off behavior.

  15. Prediction of material removal rate and surface roughness for wire electrical discharge machining of nickel using response surface methodology

    Directory of Open Access Journals (Sweden)

    Thangam Chinnadurai

    2016-12-01

    Full Text Available This study focuses on investigating the effects of process parameters, namely, Peak current (Ip, Pulse on time (Ton, Pulse off time (Toff, Water pressure (Wp, Wire feed rate (Wf, Wire tension (Wt, Servo voltage (Sv and Servo feed setting (Sfs, on the Material Removal Rate (MRR and Surface Roughness (SR for Wire electrical discharge machining (Wire-EDM of nickel using Taguchi method. Response Surface Methodology (RSM is adopted to evolve mathematical relationships between the wire cutting process parameters and the output variables of the weld joint to determine the welding input parameters that lead to the desired optimal wire cutting quality. Besides, using response surface plots, the interaction effects of process parameters on the responses are analyzed and discussed. The statistical software Mini-tab is used to establish the design and to obtain the regression equations. The developed mathematical models are tested by analysis-of-variance (ANOVA method to check their appropriateness and suitability. Finally, a comparison is made between measured and calculated results, which are in good agreement. This indicates that the developed models can predict the responses accurately and precisely within the limits of cutting parameter being used.

  16. Prediction of material removal rate and surface roughness for wire electrical discharge machining of nickel using response surface methodology

    International Nuclear Information System (INIS)

    Chinnadurai, T.; Vendan, S.A.

    2016-01-01

    This study focuses on investigating the effects of process parameters, namely, Peak current (Ip), Pulse on time (Ton), Pulse off time (Toff), Water pressure (Wp), Wire feed rate (Wf), Wire tension (Wt), Servo voltage (Sv) and Servo feed setting (Sfs), on the Material Removal Rate (MRR) and Surface Roughness (SR) for Wire electrical discharge machining (Wire-EDM) of nickel using Taguchi method. Response Surface Methodology (RSM) is adopted to evolve mathematical relationships between the wire cutting process parameters and the output variables of the weld joint to determine the welding input parameters that lead to the desired optimal wire cutting quality. Besides, using response surface plots, the interaction effects of process parameters on the responses are analyzed and discussed. The statistical software Mini-tab is used to establish the design and to obtain the regression equations. The developed mathematical models are tested by analysis-of-variance (ANOVA) method to check their appropriateness and suitability. Finally, a comparison is made between measured and calculated results, which are in good agreement. This indicates that the developed models can predict the responses accurately and precisely within the limits of cutting parameter being used. (Author)

  17. Prediction of material removal rate and surface roughness for wire electrical discharge machining of nickel using response surface methodology

    Energy Technology Data Exchange (ETDEWEB)

    Chinnadurai, T.; Vendan, S.A.

    2016-07-01

    This study focuses on investigating the effects of process parameters, namely, Peak current (Ip), Pulse on time (Ton), Pulse off time (Toff), Water pressure (Wp), Wire feed rate (Wf), Wire tension (Wt), Servo voltage (Sv) and Servo feed setting (Sfs), on the Material Removal Rate (MRR) and Surface Roughness (SR) for Wire electrical discharge machining (Wire-EDM) of nickel using Taguchi method. Response Surface Methodology (RSM) is adopted to evolve mathematical relationships between the wire cutting process parameters and the output variables of the weld joint to determine the welding input parameters that lead to the desired optimal wire cutting quality. Besides, using response surface plots, the interaction effects of process parameters on the responses are analyzed and discussed. The statistical software Mini-tab is used to establish the design and to obtain the regression equations. The developed mathematical models are tested by analysis-of-variance (ANOVA) method to check their appropriateness and suitability. Finally, a comparison is made between measured and calculated results, which are in good agreement. This indicates that the developed models can predict the responses accurately and precisely within the limits of cutting parameter being used. (Author)

  18. Capturing Structural Snapshots during Photochemical Reactions with Ultrafast Raman Spectroscopy: From Materials Transformation to Biosensor Responses.

    Science.gov (United States)

    Fang, Chong; Tang, Longteng; Oscar, Breland G; Chen, Cheng

    2018-06-21

    Chemistry studies the composition, structure, properties, and transformation of matter. A mechanistic understanding of the pertinent processes is required to translate fundamental knowledge into practical applications. The current development of ultrafast Raman as a powerful time-resolved vibrational technique, particularly femtosecond stimulated Raman spectroscopy (FSRS), has shed light on the structure-energy-function relationships of various photosensitive systems. This Perspective reviews recent work incorporating optical innovations, including the broad-band up-converted multicolor array (BUMA) into a tunable FSRS setup, and demonstrates its resolving power to watch metal speciation and photolysis, leading to high-quality thin films, and fluorescence modulation of chimeric protein biosensors for calcium ion imaging. We discuss advantages of performing FSRS in the mixed time-frequency domain and present strategies to delineate mechanisms by tracking low-frequency modes and systematically modifying chemical structures with specific functional groups. These unique insights at the chemical-bond level have started to enable the rational design and precise control of functional molecular machines in optical, materials, energy, and life sciences.

  19. Human biological monitoring for exposure assessment in response to an incident involving hazardous materials.

    Science.gov (United States)

    Scheepers, Paul T J; van Brederode, Nelly E; Bos, Peter M J; Nijhuis, Nicole J; van de Weerdt, Rik H J; van der Woude, Irene; Eggens, Martin L

    2014-12-15

    Biological monitoring in humans (HBM) is widely used in the field of occupational and environmental health. In the situation of an unexpected release of hazardous materials HBM may contribute to the medical support and treatment of exposed individuals from the general population or of emergency responders. Such exposure information may also be used to respond to individual concerns such as questions about a possible relationship between the chemicals released during the incident and health effects. In The Netherlands a guideline was prepared to support early decision-making about the possible use of HBM for exposure assessment during or as soon as possible following a chemical incident. The application of HBM in such an emergency setting is not much different from situations where HBM is normally used but there are some issues that need extra attention such as the choice of the biomarker, the biological media to be sampled, the time point at which biological samples should be collected, the ethics approval and technical implementation of the study protocol and the interpretation and communication of the study results. These issues addressed in the new guideline will support the use of HBM in the management of chemical disasters. Copyright © 2014 Elsevier Ireland Ltd. All rights reserved.

  20. Cellular responses of bioabsorbable polymeric material and Guglielmi detachable coil in experimental aneurysms.

    Science.gov (United States)

    Murayama, Yuichi; Viñuela, Fernando; Tateshima, Satoshi; Gonzalez, Nestor R; Song, Joon K; Mahdavieh, Haleh; Iruela-Arispe, Luisa

    2002-04-01

    Acceleration of healing mechanisms is a promising approach to improve current limitations of endovascular aneurysm therapy with the use of platinum coils. We evaluated a new endovascular therapeutic, bioabsorbable polymeric material (BPM), which may promote cellular reaction in the aneurysms. Four different concentrations of lactide/glycolic acid copolymer [poly(D-L-lactic-co-glycolic acid)] (PLGA), 85/15, 75/25, 65/35, and 50/50, were used as BPMs. Sixteen experimental aneurysms were created in 8 swine. Eight-millimeter-long spiral-shaped BPMs were surgically implanted in the aneurysms without tight packing (n=3 for each BPM). Guglielmi detachable coils (GDCs) were used as control (n=4). The animals were killed 14 days after embolization, and angiographic, histological, and immunohistochemical analyses were performed. Despite loose packing of aneurysms with BPMs, faster BPMs such as 50/50 or 65/35 PLGA demonstrated more mature collagen formation and fibrosis in the sac and neck of the aneurysm. One aneurysm treated with 65/35 PLGA, 1 treated with 75/25 PLGA, and all 3 treated with 85/15 PLGA showed a neck remnant on angiography. There was a linear relationship between collagen levels and polymer degradation properties (r=-0.9513). This preliminary animal study indicates that acceleration of aneurysm healing with the use of BPM is feasible. This concept can be applied to decrease and perhaps prevent aneurysmal recanalization after endovascular treatment of cerebral aneurysms.