Finite Element Analysis of Circular Plate using SolidWorks
Kang, Yeo Jin; Jhung, Myung Jo [Korea Institute of Nuclear Safety, Daejeon (Korea, Republic of)
2011-10-15
Circular plates are used extensively in mechanical engineering for nuclear reactor internal components. The examples in the reactor vessel internals are upper guide structure support plate, fuel alignment plate, lower support plate etc. To verify the structural integrity of these plates, the finite element analyses are performed, which require the development of the finite element model. Sometimes it is very costly and time consuming to make the model especially for the beginners who start their engineering job for the structural analysis, necessitating a simple method to develop the finite element model for the pursuing structural analysis. Therefore in this study, the input decks are generated for the finite element analysis of a circular plate as shown in Fig. 1, which can be used for the structural analysis such as modal analysis, response spectrum analysis, stress analysis, etc using the commercial program Solid Works. The example problems are solved and the results are included for analysts to perform easily the finite element analysis of the mechanical plate components due to various loadings. The various results presented in this study would be helpful not only for the benchmark calculations and results comparisons but also as a part of the knowledge management for the future generation of young designers, scientists and computer analysts
Design Through Manufacturing: The Solid Model - Finite Element Analysis Interface
Rubin, Carol
2003-01-01
State-of-the-art computer aided design (CAD) presently affords engineers the opportunity to create solid models of machine parts which reflect every detail of the finished product. Ideally, these models should fulfill two very important functions: (1) they must provide numerical control information for automated manufacturing of precision parts, and (2) they must enable analysts to easily evaluate the stress levels (using finite element analysis - FEA) for all structurally significant parts used in space missions. Today's state-of-the-art CAD programs perform function (1) very well, providing an excellent model for precision manufacturing. But they do not provide a straightforward and simple means of automating the translation from CAD to FEA models, especially for aircraft-type structures. The research performed during the fellowship period investigated the transition process from the solid CAD model to the FEA stress analysis model with the final goal of creating an automatic interface between the two. During the period of the fellowship a detailed multi-year program for the development of such an interface was created. The ultimate goal of this program will be the development of a fully parameterized automatic ProE/FEA translator for parts and assemblies, with the incorporation of data base management into the solution, and ultimately including computational fluid dynamics and thermal modeling in the interface.
Finite Element Analysis of the Crack Propagation for Solid Materials
Miloud Souiyah
2009-01-01
Full Text Available Problem statement: The use of fracture mechanics techniques in the assessment of performance and reliability of structure is on increase and the prediction of crack propagation in structure play important part. The finite element method is widely used for the evaluation of SIF for various types of crack configurations. Source code program of two-dimensional finite element model had been developed, to demonstrate the capability and its limitations, in predicting the crack propagation trajectory and the SIF values under linear elastic fracture analysis. Approach: Two different geometries were used on this finite element model in order, to analyze the reliability of this program on the crack propagation in linear and nonlinear elastic fracture mechanics. These geometries were namely; a rectangular plate with crack emanating from square-hole and Double Edge Notched Plate (DENT. Where, both geometries are in tensile loading and under mode I conditions. In addition, the source code program of this model was written by FORTRAN language. Therefore, a Displacement Extrapolation Technique (DET was employed particularly, to predict the crack propagations directions and to, calculate the Stress Intensity Factors (SIFs. Furthermore, the mesh for the finite elements was the unstructured type; generated using the advancing front method. And, the global h-type adaptive mesh was adopted based on the norm stress error estimator. While, the quarter-point singular elements were uniformly generated around the crack tip in the form of a rosette. Moreover, make a comparison between this current study with other relevant and published research study. Results: The application of the source code program of 2-D finite element model showed a significant result on linear elastic fracture mechanics. Based on the findings of the two different geometries from the current study, the result showed a good agreement. And, it seems like very close compare to the other published
Le, Duy Michael; Sorensen, Hanne R.; Meyer, Anne S.
2017-01-01
Elemental analysis by X-ray fluorescence spectrometry (XRF) of solid samples from a biorefinery process was performed to study the behaviour of mineral elements in a process involving hydrothermal pretreatment of biomass (wheat straw, corn stover, sugarcane bagasse, palm oil empty fruit bunches......, poplar) followed by enzymatic hydrolysis and fermentation. For all the different biomasses, the biorefinery process concentrated silicon, aluminium, and calcium in the solid fraction, while potassium and magnesium were solubilised in the process and removed from the solid fraction. Sodium concentrations...
A Finite-Element Analysis on the Rheorolling Process of Semi-Solid Spring Steel
Hongbo DONG; Yonglin KANG
2003-01-01
With a geometrical model of porous material, a 3D finite-element analysis on the rolling process of spring steel60Si2Mn in the semi-solid state is carried out using software MARC. In terms of flat and groove rolling conditions,stress field and strain fiel
Solid Modeling and Finite Element Analysis of an Overhead Crane Bridge
C. Alkin
2005-01-01
Full Text Available The design of an overhead crane bridge with a double box girder has been investigated and a case study of a crane with 35 ton capacity and 13 m span length has been conducted. In the initial phase of the case study, conventional design calculations proposed by F. E. M. Rules and DIN standards were performed to verify the stress and deflection levels. The crane design was modeled using both solids and surfaces. Finite element meshes with 4-node tetrahedral and 4-node quadrilateral shell elements were generated from the solid and shell models, respectively. After a comparison of the finite element analyses, the conventional calculations and performance of the existing crane, the analysis with quadratic shell elements was found to give the most realistic results. As a result of this study, a design optimization method for an overhead crane is proposed.
Nonlinear solid finite element analysis of mitral valves with heterogeneous leaflet layers
Prot, V.; Skallerud, B.
2009-02-01
An incompressible transversely isotropic hyperelastic material for solid finite element analysis of a porcine mitral valve response is described. The material model implementation is checked in single element tests and compared with a membrane implementation in an out-of-plane loading test to study how the layered structures modify the stress response for a simple geometry. Three different collagen layer arrangements are used in finite element analysis of the mitral valve. When the leaflets are arranged in two layers with the collagen on the ventricular side, the stress in the fibre direction through the thickness in the central part of the anterior leaflet is homogenized and the peak stress is reduced. A simulation using membrane elements is also carried out for comparison with the solid finite element results. Compared to echocardiographic measurements, the finite element models bulge too much in the left atrium. This may be due to evidence of active muscle fibres in some parts of the anterior leaflet, whereas our constitutive modelling is based on passive material.
SEACAS Theory Manuals: Part III. Finite Element Analysis in Nonlinear Solid Mechanics
Laursen, T.A.; Attaway, S.W.; Zadoks, R.I.
1999-03-01
This report outlines the application of finite element methodology to large deformation solid mechanics problems, detailing also some of the key technological issues that effective finite element formulations must address. The presentation is organized into three major portions: first, a discussion of finite element discretization from the global point of view, emphasizing the relationship between a virtual work principle and the associated fully discrete system, second, a discussion of finite element technology, emphasizing the important theoretical and practical features associated with an individual finite element; and third, detailed description of specific elements that enjoy widespread use, providing some examples of the theoretical ideas already described. Descriptions of problem formulation in nonlinear solid mechanics, nonlinear continuum mechanics, and constitutive modeling are given in three companion reports.
Song Haiyan
2017-01-01
Full Text Available It is important to study the properties and mechanics of egg drop impacts in order to reduce egg loss during processing and logistics and to provide a basis for the protective packaging of egg products. In this paper, we present the results of our study of the effects of the structural parameters on the mechanical properties of an egg using a finite element model of the egg. Based on Fluid-Solid coupling theory, a finite element model of an egg was constructed using ADINA, a finite element calculation and analysis software package. To simplify the model, the internal fluid of the egg was considered to be a homogeneous substance. The egg drop impact was simulated by the coupling solution, and the feasibility of the model was verified by comparison with the experimental results of a drop test. In summary, the modeling scheme was shown to be feasible and the simulation results provide a theoretical basis for the optimum design of egg packaging and egg processing equipment.
Quadratic solid-shell elements for nonlinear structural analysis and sheet metal forming simulation
Wang, Peng; Chalal, Hocine; Abed-Meraim, Farid
2017-01-01
In this paper, two quadratic solid-shell (SHB) elements are proposed for the three-dimensional modeling of thin structures. These consist of a 20-node hexahedral solid-shell element, denoted SHB20, and its 15-node prismatic counterpart, denoted SHB15. The formulation of these elements is extended in this work to include geometric and material nonlinearities, for application to problems involving large displacements and rotations as well as plasticity. For this purpose, the SHB elements are coupled with large-strain anisotropic elasto-plastic constitutive equations for metallic materials. Although based on a purely three-dimensional approach, several modifications are introduced in the formulation of these elements to provide them with interesting shell features. In particular, a special direction is chosen to represent the thickness, along which a user-defined number of integration points are located. Furthermore, for efficiency requirements and for alleviating locking phenomena, an in-plane reduced-integration scheme is adopted. The resulting formulations are implemented into the finite element software ABAQUS/Standard and, to assess their performance, a variety of nonlinear benchmark problems are investigated. Attention is then focused on the simulation of various complex sheet metal forming processes, involving large strain, anisotropic plasticity, and double-sided contact. From all simulation results, it appears that the SHB elements represent an interesting alternative to traditional shell and solid elements, due to their versatility and capability of accurately modeling selective nonlinear benchmark problems as well as complex sheet metal forming processes.
Quadratic solid-shell elements for nonlinear structural analysis and sheet metal forming simulation
Wang, Peng; Chalal, Hocine; Abed-Meraim, Farid
2016-10-01
In this paper, two quadratic solid-shell (SHB) elements are proposed for the three-dimensional modeling of thin structures. These consist of a 20-node hexahedral solid-shell element, denoted SHB20, and its 15-node prismatic counterpart, denoted SHB15. The formulation of these elements is extended in this work to include geometric and material nonlinearities, for application to problems involving large displacements and rotations as well as plasticity. For this purpose, the SHB elements are coupled with large-strain anisotropic elasto-plastic constitutive equations for metallic materials. Although based on a purely three-dimensional approach, several modifications are introduced in the formulation of these elements to provide them with interesting shell features. In particular, a special direction is chosen to represent the thickness, along which a user-defined number of integration points are located. Furthermore, for efficiency requirements and for alleviating locking phenomena, an in-plane reduced-integration scheme is adopted. The resulting formulations are implemented into the finite element software ABAQUS/Standard and, to assess their performance, a variety of nonlinear benchmark problems are investigated. Attention is then focused on the simulation of various complex sheet metal forming processes, involving large strain, anisotropic plasticity, and double-sided contact. From all simulation results, it appears that the SHB elements represent an interesting alternative to traditional shell and solid elements, due to their versatility and capability of accurately modeling selective nonlinear benchmark problems as well as complex sheet metal forming processes.
A hybrid-stress solid-shell element for non-linear analysis of piezoelectric structures
SZE; K; Y
2009-01-01
This paper presents eight-node solid-shell elements for geometric non-linear analyze of piezoelectric structures. To subdue shear, trapezoidal and thickness locking, the assumed natural strain method and an ad hoc modified generalized laminate stiffness matrix are employed. With the generalized stresses arising from the modified generalized laminate stiffness matrix assumed to be independent from the ones obtained from the displacement, an extended Hellinger-Reissner functional can be derived. By choosing the assumed generalized stresses similar to the assumed stresses of a previous solid ele- ment, a hybrid-stress solid-shell element is formulated. The presented finite shell element is able to model arbitrary curved shell structures. Non-linear numerical examples demonstrate the ability of the proposed model to analyze nonlinear piezoelectric devices.
Direct Transient Analysis of a Fuze Assembly by Axisymmetric Solid Elements
Dai, C. C.; Yang, J. C. S.; Titus, J.
1985-01-01
A fuze assembly, which consists of three major parts, nose, collar and sleeve, was designed to survive severe transverse impact giving a maximum base acceleration of 20.000 G. It is shown that hoop failure occurred in the collar after the impact. They also showed that by bonding the collar to the nose, the collar was able to survive the same impact. To find out the effectiveness of the bonding quantitatively, axisymmetric solid elements TRAPAX and TRIAAX were used in modelling the fuze and direct transient analysis was performed. The dynamic stresses in selected elements on the bonded and unbonded collars were compared. The peak hoop stresses in the unbonded collar were found to be up to three times higher than those in the bonded collar. The NASTRAN results explained the observed hoop failure in the unbonded collar. In addition, static and eigenvalue runs were performed as checks on the models prior to the transient runs. The use of the MPCAX cards and the existence and contributors of the calculated first several nearly identical natural frequencies are addressed.
Finite element procedures for coupled linear analysis of heat transfer, fluid and solid mechanics
Sutjahjo, Edhi; Chamis, Christos C.
1993-01-01
Coupled finite element formulations for fluid mechanics, heat transfer, and solid mechanics are derived from the conservation laws for energy, mass, and momentum. To model the physics of interactions among the participating disciplines, the linearized equations are coupled by combining domain and boundary coupling procedures. Iterative numerical solution strategy is presented to solve the equations, with the partitioning of temporal discretization implemented.
Song Haiyan; Wang Fang; Zhang Jianguo; Zhang Yinong; Yang Shugang
2017-01-01
It is important to study the properties and mechanics of egg drop impacts in order to reduce egg loss during processing and logistics and to provide a basis for the protective packaging of egg products. In this paper, we present the results of our study of the effects of the structural parameters on the mechanical properties of an egg using a finite element model of the egg. Based on Fluid-Solid coupling theory, a finite element model of an egg was constructed using ADINA, a finite element ca...
Water impact analysis of space shuttle solid rocket motor by the finite element method
Buyukozturk, O.; Hibbitt, H. D.; Sorensen, E. P.
1974-01-01
Preliminary analysis showed that the doubly curved triangular shell elements were too stiff for these shell structures. The doubly curved quadrilateral shell elements were found to give much improved results. A total of six load cases were analyzed in this study. The load cases were either those resulting from a static test using reaction straps to simulate the drop conditions or under assumed hydrodynamic conditions resulting from a drop test. The latter hydrodynamic conditions were obtained through an emperical fit of available data. Results obtained from a linear analysis were found to be consistent with results obtained elsewhere with NASTRAN and BOSOR. The nonlinear analysis showed that the originally assumed loads would result in failure of the shell structures. The nonlinear analysis also showed that it was useful to apply internal pressure as a stabilizing influence on collapse. A final analysis with an updated estimate of load conditions resulted in linear behavior up to full load.
Evaluation of Solid Modeling Software for Finite Element Analysis of Woven Ceramic Matrix Composites
Nemeth, Noel N.; Mital, Subodh; Lang, Jerry
2010-01-01
Three computer programs, used for the purpose of generating 3-D finite element models of the Repeating Unit Cell (RUC) of a textile, were examined for suitability to model woven Ceramic Matrix Composites (CMCs). The programs evaluated were the open-source available TexGen, the commercially available WiseTex, and the proprietary Composite Material Evaluator (COMATE). A five-harness-satin (5HS) weave for a melt-infiltrated (MI) silicon carbide matrix and silicon carbide fiber was selected as an example problem and the programs were tested for their ability to generate a finite element model of the RUC. The programs were also evaluated for ease-of-use and capability, particularly for the capability to introduce various defect types such as porosity, ply shifting, and nesting of a laminate. Overall, it was found that TexGen and WiseTex were useful for generating solid models of the tow geometry; however, there was a lack of consistency in generating well-conditioned finite element meshes of the tows and matrix. TexGen and WiseTex were both capable of allowing collective and individual shifting of tows within a ply and WiseTex also had a ply nesting capability. TexGen and WiseTex were sufficiently userfriendly and both included a Graphical User Interface (GUI). COMATE was satisfactory in generating a 5HS finite element mesh of an idealized weave geometry but COMATE lacked a GUI and was limited to only 5HS and 8HS weaves compared to the larger amount of weave selections available with TexGen and WiseTex.
O' Hara, Matthew J.; Kellogg, Cyndi M.; Parker, Cyrena M.; Morrison, Samuel S.; Corbey, Jordan F.; Grate, Jay W.
2017-09-01
Ammonium bifluoride (ABF, NH4F·HF) is a well-known reagent for converting metal oxides to fluorides and for its applications in breaking down minerals and ores in order to extract useful components. It has been more recently applied to the decomposition of inorganic matrices prior to elemental analysis. Herein, a sample decomposition method that employs molten ABF sample treatment in the initial step is systematically evaluated across a range of inorganic sample types: glass, quartz, zircon, soil, and pitchblende ore. Method performance is evaluated across the two variables: duration of molten ABF treatment and ABF reagent mass to sample mass ratio. The degree of solubilization of these sample classes are compared to the fluoride stoichiometry that is theoretically necessary to enact complete fluorination of the sample types. Finally, the sample decomposition method is performed on several soil and pitchblende ore standard reference materials, after which elemental constituent analysis is performed by ICP-OES and ICP-MS. Elemental recoveries are compared to the certified values; results indicate good to excellent recoveries across a range of alkaline earth, rare earth, transition metal, and actinide elements.
Mass spectrometric methods for the direct elemental and isotopic analysis of solid material
Ganeev, A. A.; Gubal, A. R.; Potapov, S. V.; Agafonova, N. N.; Nemets, V. M.
2016-04-01
Methods for the direct analysis of solids have a number of undeniable advantages over the methods that require preliminary dissolution of samples. High sensitivity and selectivity make the direct mass spectrometric techniques the most in-demand. The review concerns spark source mass spectrometry, laser ionization mass spectrometry, laser ablation inductively coupled plasma mass spectrometry, secondary ion mass spectrometry, secondary neutral mass spectrometry and glow discharge mass spectrometry. Basic principles, analytical characteristics and trends in the development of these techniques are discussed. Particular attention is given to applications of the techniques as well as to their competitive advantages and drawbacks. The bibliography includes 123 references.
MHOST: An efficient finite element program for inelastic analysis of solids and structures
Nakazawa, S.
1988-01-01
An efficient finite element program for 3-D inelastic analysis of gas turbine hot section components was constructed and validated. A novel mixed iterative solution strategy is derived from the augmented Hu-Washizu variational principle in order to nodally interpolate coordinates, displacements, deformation, strains, stresses and material properties. A series of increasingly sophisticated material models incorporated in MHOST include elasticity, secant plasticity, infinitesimal and finite deformation plasticity, creep and unified viscoplastic constitutive model proposed by Walker. A library of high performance elements is built into this computer program utilizing the concepts of selective reduced integrations and independent strain interpolations. A family of efficient solution algorithms is implemented in MHOST for linear and nonlinear equation solution including the classical Newton-Raphson, modified, quasi and secant Newton methods with optional line search and the conjugate gradient method.
Quasimodes instability analysis of uncertain asymmetric rotor system based on 3D solid element model
Zuo, Yanfei; Wang, Jianjun; Ma, Weimeng
2017-03-01
Uncertainties are considered in the equation of motion of an asymmetric rotor system. Based on Hill's determinant method, quasimodes stability analysis with uncertain parameters is used to get stochastic boundaries of unstable regions. Firstly, A 3D finite element rotor model was built in rotating frame with four parameterized coefficients, which is assumed as random parameters representing the uncertainties existing in the rotor system. Then the influences of uncertain coefficients on the distribution of the unstable region boundaries are analyzed. The results show that uncertain parameters have various influences on the size, boundary and number of unstable regions. At last, the statistic results of the minimum and maximum spin speeds of unstable regions were got by Monte Carlo simulation. The used method is suitable for real engineering rotor system, because arbitrary configuration of rotors can be modeled by 3D finite element.
Finite element analysis of ion transport in solid state nuclear waste form materials
Rabbi, F.; Brinkman, K.; Amoroso, J.; Reifsnider, K.
2017-09-01
Release of nuclear species from spent fuel ceramic waste form storage depends on the individual constituent properties as well as their internal morphology, heterogeneity and boundary conditions. Predicting the release rate is essential for designing a ceramic waste form, which is capable of effectively storing the spent fuel without contaminating the surrounding environment for a longer period of time. To predict the release rate, in the present work a conformal finite element model is developed based on the Nernst Planck Equation. The equation describes charged species transport through different media by convection, diffusion, or migration. And the transport can be driven by chemical/electrical potentials or velocity fields. The model calculates species flux in the waste form with different diffusion coefficient for each species in each constituent phase. In the work reported, a 2D approach is taken to investigate the contributions of different basic parameters in a waste form design, i.e., volume fraction, phase dispersion, phase surface area variation, phase diffusion co-efficient, boundary concentration etc. The analytical approach with preliminary results is discussed. The method is postulated to be a foundation for conformal analysis based design of heterogeneous waste form materials.
Wind Turbine Cross-Sectional Stiffness Analysis Using Internally Layered Solid Elements
Couturier, Philippe; Krenk, Steen
2016-01-01
using a single layer of displacement-based elements whereby the element's stiffness is obtained using Gaussian quadrature through each layer. The interlaminar stresses are recovered at points of interest via a three-dimensional equilibrium-based postprocessing scheme that uses the distribution of in...
TIAN Bao-guo; SI Ji-tao; ZHAO Yan; WANG Hong-tao; HAO Ji-ming
2007-01-01
This paper deals with the procedure and methodology which can be used to select the optimal treatment and disposal technology of municipal solid waste (MSW), and to provide practical and effective technical support to policy-making, on the basis of study on solid waste management status and development trend in China and abroad. Focusing on various treatment and disposal technologies and processes of MSW, this study established a Monte-Carlo mathematical model of cost minimization for MSW handling subjected to environmental constraints. A new method of element stream (such as C, H, O, N, S) analysis in combination with economic stream analysis of MSW was developed. By following the streams of different treatment processes consisting of various techniques from generation, separation, transfer, transport, treatment, recycling and disposal of the wastes, the element constitution as well as its economic distribution in terms of possibility functions was identified. Every technique step was evaluated economically. The Mont-Carlo method was then conducted for model calibration. Sensitivity analysis was also carried out to identify the most sensitive factors. Model calibration indicated that landfill with power generation of landfill gas was economically the optimal technology at the present stage under the condition of more than 58% of C, H, O, N, S going to landfill. Whether or not to generate electricity was the most sensitive factor. If landfilling cost increases, MSW separation treatment was recommended by screening first followed with incinerating partially and composting partially with residue landfilling. The possibility of incineration model selection as the optimal technology was affected by the city scale. For big cities and metropolitans with large MSW generation, possibility for constructing large-scale incineration facilities increases, whereas, for middle and small cities, the effectiveness of incinerating waste decreases.
DAgostino, Giancarlo; Giordani, Laura; Oddone, Massimo; Kipphardt, Heinrich; Richter, Silke
2013-01-01
The results of analytical measurements performed with solid-sampling techniques are affected by the distribution of the analytes within the matrix. The effect becomes significant in case of determination of trace elements in small subsamples. In this framework we propose a measurement model based on Instrumental Neutron Activation Analysis to determine the relative variability of the amount of an analyte among subsamples of a material. The measurement uncertainty is evaluated and includes the counting statistics, the full-energy gamma peak efficiency and the spatial gradient of the neutron flux at the irradiation position. The data we obtained in a neutron activation experiment and showing the relative variability of As, Au, Ir, Sb and W among subsamples of a highly pure Rh foil are also presented.
M. I. Maksud
2012-12-01
Full Text Available Printing is offering the feasibility of producing mass quantities of a wide variety of electronic components and devices quickly and at lower cost. Flexography is mainly used for packaging applications, but is also poses a potential method for the micro manufacture of electronic devices, smart packaging and RFID. The flexographic printing process poses as an attractive candidate for printing electronics for its high speed printing capabilities where such volume and large active areas need to be printed. Therefore an investigation for its potential usage in printing electronics are highly in demand hence a research for suitable conductive ink related to this process is vital. Multiple fine solid lines of high quality are essential to enable printing of ink tracks for electronic applications. A step by step approach by printing multiple solid lines, measurements of printing plates and printed images and finite element analysis (FEA need to be carried out in advance to help comprehending this process that is influenced by many interacting parameters. Plate characteristics are among a number of process parameters that will influence print line quality, which will affect the electrical performance of printed tracks. Printing trials have also been carried out in comparison various ink to check the compatibility and the suitability of the ink developed for printing RFID antennas.
Heat transfer monitoring in solids by means of finite element analysis software
Hernandez W, J.; Suarez, V.; Guarachi, J.; Calderon, A.; Juarez, A. G.; Rojas T, J. B.; Marin, E. [IPN, Centro de Investigacion en Ciencia Aplicada y Tecnologia Avanzada, Calz. Legaria No. 694, Col. Irrigacion, 11500 Mexico D. F. (Mexico)
2012-10-15
We study the radial heat transfer in a homogeneous and isotropic substance with a heat linear source in its axial axis. For this, we used hot wire photothermal technique in order to obtain the temperature distribution as a function of radial distance and time exposure. Also, the solution of the transient heat transport equation for this problem was obtained with appropriate boundary conditions, by means of finite element technique. The comparison of the experimental and simulated results shows a good agree, which demonstrate the utility of this methodology in the investigation of the thermal response of substances, in the radial configuration. (Author)
Thermal stress analysis of ceramic structures with NASTRAN isoparametric solid elements
Lamberson, S. E.; Paul, D. B.
1978-01-01
The performance of the NASTRAN level 16.0, twenty node, isoparametric bricks (CIHEX2) at thermal loading was studied. A free ceramic plate was modelled using twenty node bricks of varying thicknesses. The thermal loading for this problem was uniform over the surface with an extremely large gradient through the thickness. No mechanical loading was considered. Temperature-dependent mechanical properties were considered in this analysis. The NASTRAN results were compared to one dimensional stress distributions calculated by direct numerical integration.
Limit-point buckling analyses using solid, shell and solid.shell elements
Killpack, Marc; Abed-Meraim, Farid [CNRS, Metz Cedex (France)
2011-05-15
In this paper, the recently-developed solid-shell element SHB8PS is used for the analysis of a representative set of popular limit-point buckling benchmark problems. For this purpose, the element has been implemented in Abaqus/Standard finite element software and the modified Riks method was employed as an efficient path-following strategy. For the benchmark problems tested, the new element shows better performance compared to solid elements and often performs as well as state-of-the-art shell elements. In contrast to shell elements, it allows for the accurate prescription of boundary conditions as applied to the actual edges of the structure.
Adamenko, S V
2003-01-01
We present the results of the experimental study on synthesis of a wide range of isotopes in a superdense plasma. The initial conditions necessary for plasma bunch formation were provided by specially organized coherent impact on a solid target with a total energy up to 1 kJ. More than 4000 shots were performed with various targets made of light, medium, and heavy elements. Subsequent analysis of the products of the target explosion reveals the presence of a wide range of elements absent in the initial materials. Elements with nuclei three and more times heavier than the nucleus of the target main element are detected in the products. The isotopic composition of the produced elements significantly differs from the natural one. The presence of unknown superheavy elements at the border of the periodic table and beyond it was detected by several different spectroscopic methods of elemental and isotopic analyzes.
Platonov, V.V.; Shvykin, A.Y.; Proskuryakov, V.A.; Podshibyakin, S.I.; Chilachava, K.B.; Khmarin, E.M.; Solov' ev, A.S. [Tolstoy Tula State Pedagogical University, Tula (Russian Federation)
2002-07-01
A procedure was developed for gas-chromatographic elemental analysis of coals. The conditions of exhaustive oxidation of weighed microportions of the coals were optimized. The procedure of calculating the results of analysis was modified with the aim to improve its reproducibility.
Program ELM: A tool for rapid thermal-hydraulic analysis of solid-core nuclear rocket fuel elements
Walton, James T.
1992-01-01
This report reviews the state of the art of thermal-hydraulic analysis codes and presents a new code, Program ELM, for analysis of fuel elements. ELM is a concise computational tool for modeling the steady-state thermal-hydraulics of propellant flow through fuel element coolant channels in a nuclear thermal rocket reactor with axial coolant passages. The program was developed as a tool to swiftly evaluate various heat transfer coefficient and friction factor correlations generated for turbulent pipe flow with heat addition which have been used in previous programs. Thus, a consistent comparison of these correlations was performed, as well as a comparison with data from the NRX reactor experiments from the Nuclear Engine for Rocket Vehicle Applications (NERVA) project. This report describes the ELM Program algorithm, input/output, and validation efforts and provides a listing of the code.
Saunders, Marnie M; Schwentker, Edwards P; Kay, David B; Bennett, Gordon; Jacobs, Christopher R; Verstraete, Mary C; Njus, Glen O
2003-02-01
In this study, we developed an approach for prosthetic foot design incorporating motion analysis, mechanical testing and computer analysis. Using computer modeling and finite element analysis, a three-dimensional (3D), numerical foot model of the solid ankle cushioned heel (SACH) foot was constructed and analyzed based upon loading conditions obtained from the gait analysis of an amputee and validated experimentally using mechanical testing. The model was then used to address effects of viscoelastic heel performance numerically. This is just one example of the type of parametric analysis and design enabled by this approach. More importantly, by incorporating the unique gait characteristics of the amputee, these parametric analyses may lead to prosthetic feet more appropriately representing a particular user's needs, comfort and activity level.
Mohammad eNikkhoo
2015-01-01
Full Text Available The risk of low back pain resulted from cyclic loadings is greater than that resulted from prolonged static postures. Disc degeneration results in degradation of disc solid structures and decrease of water contents, which is caused by activation of matrix digestive enzymes. The mechanical responses resulted from internal solid-fluid interactions of degenerative discs to cyclic loadings are not well studied yet. The fluid-solid interactions in discs can be evaluated by mathematical models, especially the poroelastic finite element models. We developed a robust disc poroelastic FE model to analyze the effect of degeneration on solid-fluid interactions within disc subjected to cyclic loadings at different loading frequencies. A backward analysis combined with in-vitro experiments were used to find the elastic modulus and hydraulic permeability of intact and enzyme-induced degenerated porcine discs. The results showed that the averaged peak-to-peak disc deformations during the in-vitro cyclic tests were well fitted with limited FE simulations and a quadratic response surface regression for both disc groups. The results showed that higher loading frequency increased the intradiscal pressure, decreased the total fluid loss, and slightly increased the maximum axial stress within solid matrix. Enzyme-induced degeneration decreased the intradiscal pressure and total fluid loss, and barely changed the maximum axial stress within solid matrix. The increase of intradiscal pressure and total fluid loss with loading frequency was less sensitive after the frequency elevated to 0.1 Hz for the enzyme-induced degenerated disc. Based on this study, it is found that enzyme-induced degeneration decreases energy attenuation capability of disc, but less change the strength of disc.
Advanced solid elements for sheet metal forming simulation
Mataix, Vicente; Rossi, Riccardo; Oñate, Eugenio; Flores, Fernando G.
2016-08-01
The solid-shells are an attractive kind of element for the simulation of forming processes, due to the fact that any kind of generic 3D constitutive law can be employed without any additional hypothesis. The present work consists in the improvement of a triangular prism solid-shell originally developed by Flores[2, 3]. The solid-shell can be used in the analysis of thin/thick shell, undergoing large deformations. The element is formulated in total Lagrangian formulation, and employs the neighbour (adjacent) elements to perform a local patch to enrich the displacement field. In the original formulation a modified right Cauchy-Green deformation tensor (C) is obtained; in the present work a modified deformation gradient (F) is obtained, which allows to generalise the methodology and allows to employ the Pull-Back and Push-Forwards operations. The element is based in three modifications: (a) a classical assumed strain approach for transverse shear strains (b) an assumed strain approach for the in-plane components using information from neighbour elements and (c) an averaging of the volumetric strain over the element. The objective is to use this type of elements for the simulation of shells avoiding transverse shear locking, improving the membrane behaviour of the in-plane triangle and to handle quasi-incompressible materials or materials with isochoric plastic flow.
ELM - A SIMPLE TOOL FOR THERMAL-HYDRAULIC ANALYSIS OF SOLID-CORE NUCLEAR ROCKET FUEL ELEMENTS
Walton, J. T.
1994-01-01
ELM is a simple computational tool for modeling the steady-state thermal-hydraulics of propellant flow through fuel element coolant channels in nuclear thermal rockets. Written for the nuclear propulsion project of the Space Exploration Initiative, ELM evaluates the various heat transfer coefficient and friction factor correlations available for turbulent pipe flow with heat addition. In the past, these correlations were found in different reactor analysis codes, but now comparisons are possible within one program. The logic of ELM is based on the one-dimensional conservation of energy in combination with Newton's Law of Cooling to determine the bulk flow temperature and the wall temperature across a control volume. Since the control volume is an incremental length of tube, the corresponding pressure drop is determined by application of the Law of Conservation of Momentum. The size, speed, and accuracy of ELM make it a simple tool for use in fuel element parametric studies. ELM is a machine independent program written in FORTRAN 77. It has been successfully compiled on an IBM PC compatible running MS-DOS using Lahey FORTRAN 77, a DEC VAX series computer running VMS, and a Sun4 series computer running SunOS UNIX. ELM requires 565K of RAM under SunOS 4.1, 360K of RAM under VMS 5.4, and 406K of RAM under MS-DOS. Because this program is machine independent, no executable is provided on the distribution media. The standard distribution medium for ELM is one 5.25 inch 360K MS-DOS format diskette. ELM was developed in 1991. DEC, VAX, and VMS are trademarks of Digital Equipment Corporation. Sun4 and SunOS are trademarks of Sun Microsystems, Inc. IBM PC is a registered trademark of International Business Machines. MS-DOS is a registered trademark of Microsoft Corporation.
陈兆勇; 倪国林
2011-01-01
Common method of finite element analysis for garbage truck body using solidworks was introduced. The analytical thinking and the technique of modeling, meshing, load definition and component connection while processing were elaborated.%介绍了运用SolidWorks软件对垃圾车厢体进行有限元分析的一般方法。着重阐述了分析思路以及在分析过程中的建模、网格划分、载荷定义、零件接触等方面的技巧。
2010-01-01
Finite element analysis is an engineering method for the numerical analysis of complex structures. This book provides a bird's eye view on this very broad matter through 27 original and innovative research studies exhibiting various investigation directions. Through its chapters the reader will have access to works related to Biomedical Engineering, Materials Engineering, Process Analysis and Civil Engineering. The text is addressed not only to researchers, but also to professional engineers, engineering lecturers and students seeking to gain a better understanding of where Finite Element Analysis stands today.
Pardo, D.; Branner, K.
2005-01-01
A very detailed 2D-solid finite element model is developed representing the load carrying box girder of a wind turbine blade. Using typical geometrical values for the girder dimensions and public available material data, the overall cross-sectional behaviour is analysed for a simple compressive...
Nee, John G.; Kare, Audhut P.
1987-01-01
Explores several concepts in computer assisted design/computer assisted manufacturing (CAD/CAM). Defines, evaluates, reviews and compares advanced computer-aided geometric modeling and analysis techniques. Presents the results of a survey to establish the capabilities of minicomputer based-systems with the CAD/CAM packages evaluated. (CW)
Moreno-García, Pavel; Grimaudo, Valentine; Riedo, Andreas; Neuland, Maike B.; Tulej, Marek; Broekmann, Peter; Wurz, Peter
2016-04-01
Direct quantitative chemical analysis with high lateral and vertical resolution of solid materials is of prime importance for the development of a wide variety of research fields, including e.g., astrobiology, archeology, mineralogy, electronics, among many others. Nowadays, studies carried out by complementary state-of-the-art analytical techniques such as Auger Electron Spectroscopy (AES), X-ray Photoelectron Spectroscopy (XPS), Secondary Ion Mass Spectrometry (SIMS), Glow Discharge Time-of-Flight Mass Spectrometry (GD-TOF-MS) or Laser Ablation Inductively Coupled Plasma Mass Spectrometry (LA-ICP-MS) provide extensive insight into the chemical composition and allow for a deep understanding of processes that might have fashioned the outmost layers of an analyte due to its interaction with the surrounding environment. Nonetheless, these investigations typically employ equipment that is not suitable for implementation on spacecraft, where requirements concerning weight, size and power consumption are very strict. In recent years Laser Ablation/Ionization Mass Spectrometry (LIMS) has re-emerged as a powerful analytical technique suitable not only for laboratory but also for space applications.[1-3] Its improved performance and measurement capabilities result from the use of cutting edge ultra-short femtosecond laser sources, improved vacuum technology and fast electronics. Because of its ultimate compactness, simplicity and robustness it has already proven to be a very suitable analytical tool for elemental and isotope investigations in space research.[4] In this contribution we demonstrate extended capabilities of our LMS instrument by means of three case studies: i) 2D chemical imaging performed on an Allende meteorite sample,[5] ii) depth profiling with unprecedented sub-nm vertical resolution on Cu electrodeposited interconnects[6,7] and iii) preliminary molecular desorption of polymers without assistance of matrix or functionalized substrates.[8] On the whole
Elemental analysis in biotechnology.
Hann, Stephan; Dernovics, Mihaly; Koellensperger, Gunda
2015-02-01
This article focuses on analytical strategies integrating atomic spectroscopy in biotechnology. The rationale behind developing such methods is inherently linked to unique features of the key technique in elemental analysis, which is inductively coupled plasma mass spectrometry: (1) the high sensitivity and selectivity of state of the art instrumentation, (2) the possibility of accurate absolute quantification even in complex matrices, (3) the capability of combining elemental detectors with chromatographic separation methods and the versatility of the latter approach, (4) the complementarity of inorganic and organic mass spectrometry, (5) the multi-element capability and finally (6) the capability of isotopic analysis. The article highlights the most recent bio-analytical developments exploiting these methodological advantages and shows the potential in biotechnological applications.
Non-drainage scleral buckling with solid silicone elements
Pukhraj Rishi
2014-01-01
Full Text Available Background: With the increasing number of cataract surgeries, incidence of posterior segment complications including rhegmatogenous retinal detachment (RRD is likely to rise. Scleral buckling (SB surgery is an effective and less expensive option. The primary advantage of non-drainage procedure is avoidance of possible complications associated with trans-choroidal drainage. The aim of present study is to describe the clinical profile of subjects undergoing non-drainage SB surgery with solid silicone elements for RRD and analyze their treatment outcomes. Materials and Methods: This was a retrospective, non-randomized, interventional study at a tertiary care center. Three hundred and six eyes of 298 patients undergoing non-drainage SB surgery with solid silicone elements from year 2000 to 2006 were included. Inclusion criteria were primary RRD, peripheral depressible retinal break, media clarity affording peripheral retinal view and proliferative vitreo-retinopathy (PVR up to grade C2. Uni- and multivariate analyses was done to analyze factors affecting anatomical and visual outcomes. Statistical analysis was performed using SPSS Version 10. Results: Mean follow-up was 303 ± 393.33 days. Primary anatomical success was obtained in 279 (91.2% eyes; primary functional success in 286 (93.5% eyes. PVR (grade B or C, intraocular pressure <10 mm Hg and the inability to find a retinal break were significantly associated with final anatomical failure. Baseline vision ≤3/60 was significantly associated with poor visual recovery. Conclusions: SB surgery is reasonably safe and highly efficacious. Solid silicone elements are effective in non-drainage SB surgery. However, case selection is important.
Sprecher, David A
2010-01-01
This classic text in introductory analysis delineates and explores the intermediate steps between the basics of calculus and the ultimate stage of mathematics: abstraction and generalization.Since many abstractions and generalizations originate with the real line, the author has made it the unifying theme of the text, constructing the real number system from the point of view of a Cauchy sequence (a step which Dr. Sprecher feels is essential to learn what the real number system is).The material covered in Elements of Real Analysis should be accessible to those who have completed a course in
Geometrical frustration in an element solid: (beta)-rhombohedral boron
Ogitsu, T; Gygi, F; Reed, J; Udagawa, M; Motome, Y; Schwegler, E; Galli, G
2009-05-19
Although a comprehensive understanding of the basic properties of most elemental solids has been achieved, there are still fundamental, open questions regarding simple substances, e.g. boron. Based on an Ising model that describes the intrinsic defect states in elemental boron, we show that this system is the only known element to exhibit geometrical frustration in its solid form. Interestingly, we find that the peculiar transport properties of boron that have been reported over the past forty years originate from the presence of geometrical frustration.
Beam section stiffness properties using a single layer of 3D solid elements
Couturier, Philippe; Krenk, Steen; Høgsberg, Jan Becker
2015-01-01
A method is presented for analysis of the properties of general cross-sections with arbitrary geometry and material distribution. The full six by six cross-section stiffness matrix is evaluated from a single element thickness slice represented by 3D solid elements with lengthwise Hermitian...... illustrate the accuracy of the method for solid and thin-walled sections with isotropic and general anisotropic materials....
Metallic elements fractionation in municipal solid waste incineration residues
Kowalski, Piotr R.; Kasina, Monika; Michalik, Marek
2016-04-01
Municipal solid waste incineration (MSWI) residues are represented by three main materials: bottom ash, fly ash and air pollution control (APC) residues. Among them ˜80 wt% is bottom ash. All of that materials are products of high temperature (>1000° C) treatment of waste. Incineration process allows to obtain significant reduction of waste mass (up to 70%) and volume (up to 90%) what is commonly used in waste management to reduce the amount need to be landfilled or managed in other way. Incineration promote accumulation non-combustible fraction of waste, which part are metallic elements. That type of concentration is object of concerns about the incineration residues impact on the environment and also gives the possibility of attempts to recover them. Metallic elements are not equally distributed among the materials. Several factors influence the process: melting points, volatility and place and forms of metallic occurrence in the incinerated waste. To investigate metallic elements distribution in MSWI residues samples from one of the biggest MSW incineration plant in Poland were collected in 2015. Chemical analysis with emphasis on the metallic elements content were performed using inductively coupled plasma optical emission (ICP-OES) and mass spectrometry (ICP-MS). The bottom ash was a SiO2-CaO-Al2O3-Fe2O3-Na2O rich material, whereas fly ash and APC residues were mostly composed of CaO and SiO2. All of the materials were rich in amorphous phase occurring together with various, mostly silicate crystalline phases. In a mass of bottom ash 11 wt% were metallic elements but also in ashes 8.5 wt% (fly ash) and ˜4.5 wt% (APC residues) of them were present. Among the metallic elements equal distribution between bottom and fly ash was observed for Al (˜3.85 wt%), Mn (770 ppm) and Ni (˜65 ppm). In bottom ash Fe (5.5 wt%), Cr (590 ppm) and Cu (1250 ppm) were concentrated. These values in comparison to fly ash were 5-fold higher for Fe, 3-fold for Cu and 1.5-fold for
Element Verification and Comparison in Sierra/Solid Mechanics Problems
Ohashi, Yuki; Roth, William
2016-05-01
The goal of this project was to study the effects of element selection on the Sierra/SM solutions to five common solid mechanics problems. A total of nine element formulations were used for each problem. The models were run multiple times with varying spatial and temporal discretization in order to ensure convergence. The first four problems have been compared to analytical solutions, and all numerical results were found to be sufficiently accurate. The penetration problem was found to have a high mesh dependence in terms of element type, mesh discretization, and meshing scheme. Also, the time to solution is shown for each problem in order to facilitate element selection when computer resources are limited.
Cui, Xiangyang; Li, She; Feng, Hui; Li, Guangyao
2017-05-01
In this paper, a novel triangular prism solid and shell interactive mapping element is proposed to solve the coupled magnetic-mechanical formulation in electromagnetic sheet metal forming process. A linear six-node ;Triprism; element is firstly proposed for transient eddy current analysis in electromagnetic field. In present ;Triprism; element, shape functions are given explicitly, and a cell-wise gradient smoothing operation is used to obtain the gradient matrices without evaluating derivatives of shape functions. In mechanical field analysis, a shear locking free triangular shell element is employed in internal force computation, and a data mapping method is developed to transfer the Lorentz force on solid into the external forces suffered by shell structure for dynamic elasto-plasticity deformation analysis. Based on the deformed triangular shell structure, a ;Triprism; element generation rule is established for updated electromagnetic analysis, which means inter-transformation of meshes between the coupled fields can be performed automatically. In addition, the dynamic moving mesh is adopted for air mesh updating based on the deformation of sheet metal. A benchmark problem is carried out for confirming the accuracy of the proposed ;Triprism; element in predicting flux density in electromagnetic field. Solutions of several EMF problems obtained by present work are compared with experiment results and those of traditional method, which are showing excellent performances of present interactive mapping element.
Trace elements in cocoa solids and chocolate: an ICPMS study.
Yanus, Rinat Levi; Sela, Hagit; Borojovich, Eitan J C; Zakon, Yevgeni; Saphier, Magal; Nikolski, Andrey; Gutflais, Efi; Lorber, Avraham; Karpas, Zeev
2014-02-01
The concentrations of eight trace elements: lead (Pb), cadmium (Cd), chromium (Cr), manganese (Mn), cobalt (Co), arsenic (As), bismuth (Bi) and molybdenum (Mo), in chocolate, cocoa beans and products were studied by ICPMS. The study examined chocolate samples from different brands and countries with different concentrations of cocoa solids from each brand. The samples were digested and filtered to remove lipids and indium was used as an internal standard to correct matrix effects. A linear correlation was found between the level of several trace elements in chocolate and the cocoa solids content. Significant levels of Bi and As were found in the cocoa bean shells but not in the cocoa bean and chocolate. This may be attributed to environmental contamination. The presence of other elements was attributed to the manufacturing processes of cocoa and chocolate products. Children, who are big consumers of chocolates, may be at risk of exceeding the daily limit of lead; whereas one 10 g cube of dark chocolate may contain as much as 20% of the daily lead oral limit. Moreover chocolate may not be the only source of lead in their nutrition. For adults there is almost no risk of exceeding daily limits for trace metals ingestion because their digestive absorption of metals is very poor. © 2013 Published by Elsevier B.V.
Structural analysis with the finite element method linear statics
Oñate, Eugenio
2013-01-01
STRUCTURAL ANALYSIS WITH THE FINITE ELEMENT METHOD Linear Statics Volume 1 : The Basis and Solids Eugenio Oñate The two volumes of this book cover most of the theoretical and computational aspects of the linear static analysis of structures with the Finite Element Method (FEM). The content of the book is based on the lecture notes of a basic course on Structural Analysis with the FEM taught by the author at the Technical University of Catalonia (UPC) in Barcelona, Spain for the last 30 years. Volume1 presents the basis of the FEM for structural analysis and a detailed description of the finite element formulation for axially loaded bars, plane elasticity problems, axisymmetric solids and general three dimensional solids. Each chapter describes the background theory for each structural model considered, details of the finite element formulation and guidelines for the application to structural engineering problems. The book includes a chapter on miscellaneous topics such as treatment of inclined supports, elas...
Coupling problem study of solid element and shell element in finite element%有限元中体壳单元的耦合问题研究
谢最伟; 吴新跃; 万强
2011-01-01
The coupling between the solid elements and the shell elements has become a difficult problem in finite element due to he discontinuousness of rotational freedom.This problem is often solved hy MPC(Multipoint Constranint)method in engineering practice.The method that constrains a certain rotational freedom of the nodes which are shared by solid element and shell element is advanced.By comparing it with the MPC method,it is proved that the method utilized in this paper is easy to realize and has a similarly high accuracy.A good reference method to solve the coupling of solid element and shell element in finite element analysis can be obtained from the method mentioned in this paper.%由于转动自由度的不连续,使得体单元与壳单元之间的耦合成为有限元计算中比较难以解决的问题.通常在工程实践中采用MPC(Multipoint Constraint)法.文中提出了约束体壳单元连接处共用节点的某一旋转自由度的方法.通过与MPC法的计算对比,证明了该方法在便于实现的同时,同样有着很高的精确度.这为有限元分析中体壳单元的耦合处理提供了一种很好的借鉴方法.
Limit analysis of solid reinforced concrete structures
Larsen, Kasper Paaske
2009-01-01
element for lower bound analysis of reinforced concrete structures is presented. The method defines the stress state at a point within the solid as a combination of concrete- and reinforcement stresses and yield criterions are applied to the stress components separately. This method allows for orthotropic......Recent studies have shown that Semidefinite Programming (SDP) can be used effectively for limit analysis of isotropic cohesive-frictional continuums using the classical Mohr-Coulomb yield criterion. In this paper we expand on this previous research by adding reinforcement to the model and a solid...... reinforcement and it is therefore possible to analyze structures with complex reinforcement layouts. Tests are conducted to validate the method against well-known analytical solutions....
Arslan, Zikri; Paulson, Anthony J
2003-01-10
Uptake of trace elements into fish otoliths is governed by several factors such as life histories and environment in addition to stock and species differences. In an attempt to elucidate the elemental signatures of rare earth elements (REEs) in otoliths, a solid phase extraction (SPE) protocol was used in combination with electrothermal vaporization (ETV) as a sample introduction procedure for the determinations by inductively coupled plasma quadrupole mass spectrometry (ICP-MS). Effects of various parameters, such as carrier gas flow rate, atomization temperature and chemical modification, were examined for optimization of the conditions by ETV-ICP-MS. Atomization was achieved at 2800 deg. C. Lower temperatures (i.e. 2600 deg. C) resulted in severe memory problems due to incomplete atomization. Palladium was used as a chemical modifier. It was found that an increase in Pd concentration up to 0.5 {mu}g in the injection volume (70 {mu}l) led up to four-fold enhancement in the integrated signals. This phenomenon is attributed to the carrier effect of Pd rather than the stabilization since no significant losses were observed for high temperature drying around 700 deg. C even in the absence of Pd. Preconcentration was performed on-line at pH 5 by using a mini-column of Toyopearl AF-Chelate 650M chelating resin, which also eliminated the calcium matrix of otolith solutions. After preconcentration of 6.4 ml of solution, the concentrate was collected in 0.65 ml of 0.5% (v/v) HNO{sub 3} in autosampler cups, and then analyzed by ETV-ICP-MS. The method was validated with the analysis of a fish otolith certified reference material (CRM) of emperor snapper, and then applied to samples. Results obtained from otoliths of fish captured in the same habitat indicated that otolith rare earth element concentrations are more dependent on environmental conditions of the habitat than on species differences.
Analysis and Design of Rolling Stock Elements
M. V. Chugunov
2014-01-01
Full Text Available The work solves the problem of equal-strength design of the rolling stock elements in option of discrete equal-strength. For this purpose, has been developed the software built in SolidWorks and SolidWorks Simulation as an AddIn-application using necessary basic functionality and extending it in the specified part on the basis of API SolidWorks and COM technology.The SolidWorks software is used to develop a 3D-model for general force frame of the wagon as an assembly. As this assembly is quite complicated and includes many elements both standard, and non-standard type, 3D - specification is developed by 3Dvia Composer software, which is included in the article in the form of the gif-animation and via-roller. This means is very useful for the evident analysis of topology and geometrical properties of a design as a whole, facilitates a procedure of adequate formation of the FE model providing accuracy and profitability of computing. From the point of view of profitability and opportunities of definition of concentrators of stresses with a sufficient accuracy for practice the combined model including volume and shell FEM is optimum.In the work the analysis results of stress-strain state of a design are given in two options of static loading in the form of stress diagrams, the main areas of stress concentration are revealed.Results of equal-strength design in the form of thickness distribution on thin-walled elements of a design, considered within FEM as shells, are received. It is shown that the developed software doesn't allow optimum design results, however it is economically viable, simple in use and can be applied to the solution of problems of rational design in design practice.SolidWorks, as well as the majority of similar CADs, possess an open architecture and allow users to apply its functionality. This work continues a series of publications of the author of this paper and other authors concerning the API-based CAD/CAE adaptation and
METHODOLOGICAL ELEMENTS OF SITUATIONAL ANALYSIS
Tetyana KOVALCHUK
2016-07-01
Full Text Available The article deals with the investigation of theoretical and methodological principles of situational analysis. The necessity of situational analysis is proved in modern conditions. The notion “situational analysis” is determined. We have concluded that situational analysis is a continuous system study which purpose is to identify dangerous situation signs, to evaluate comprehensively such signs influenced by a system of objective and subjective factors, to search for motivated targeted actions used to eliminate adverse effects of the exposure of the system to the situation now and in the future and to develop the managerial actions needed to bring the system back to norm. It is developed a methodological approach to the situational analysis, its goal is substantiated, proved the expediency of diagnostic, evaluative and searching functions in the process of situational analysis. The basic methodological elements of the situational analysis are grounded. The substantiation of the principal methodological elements of system analysis will enable the analyst to develop adaptive methods able to take into account the peculiar features of a unique object which is a situation that has emerged in a complex system, to diagnose such situation and subject it to system and in-depth analysis, to identify risks opportunities, to make timely management decisions as required by a particular period.
Nasrullah, Muhammad; Vainikka, Pasi; Hannula, Janne; Hurme, Markku; Oinas, Pekka
2016-01-01
In the production of solid recovered fuel (SRF), certain waste components have excessive influence on the quality of product. The proportion of rubber, plastic (hard) and certain textiles was found to be critical as to the elemental quality of SRF. The mass flow of rubber, plastic (hard) and textiles (to certain extent, especially synthetic textile) components from input waste stream into the output streams of SRF production was found to play the decisive role in defining the elemental quality of SRF. This paper presents the mass flow of polluting and potentially toxic elements (PTEs) in SRF production. The SRF was produced from municipal solid waste (MSW) through mechanical treatment (MT). The results showed that of the total input chlorine content to process, 55% was found in the SRF and 30% in reject material. Of the total input arsenic content, 30% was found in the SRF and 45% in fine fraction. In case of cadmium, lead and mercury, of their total input content to the process, 62%, 38% and 30%, respectively, was found in the SRF. Among the components of MSW, rubber material was identified as potential source of chlorine, containing 8.0 wt.% of chlorine. Plastic (hard) and textile components contained 1.6 and 1.1. wt.% of chlorine, respectively. Plastic (hard) contained higher lead and cadmium content compared with other waste components, i.e. 500 mg kg(-1) and 9.0 mg kg(-1), respectively.
Beam section stiffness properties using a single layer of 3D solid elements
Couturier, Philippe; Krenk, Steen; Høgsberg, Jan Becker
2015-01-01
A method is presented for analysis of the properties of general cross-sections with arbitrary geometry and material distribution. The full six by six cross-section stiffness matrix is evaluated from a single element thickness slice represented by 3D solid elements with lengthwise Hermitian...... interpolation with six independent imposed deformation modes corresponding to extension, torsion, bending and shear. The flexibility matrix of the slice is obtained from complementary elastic energy, and the stiffness matrix is obtained by extracting and inverting the cross-section flexibility. Three examples...
Saad, N.; Rella, C.; van Pelt, A.
2009-04-01
We report here on the novel employment of a small footprint Wavelength-Scanned Cavity Ring-Down Spectrometer (WS-CRDS) interfaced to an elemental analyzer for the measurement of the bulk isotopic carbon signature in plants and food products. The current system provides an inexpensive alternative with unparalleled ease-of-use as compared to standard methods using the more complex analytical instrumentation of isotope ratio mass spectrometry. A precision of carbon isotopic ratio measurements of less than 1 permil was achieved in minutes of measurement time. Such precision readily distinguishes the isotopic carbon signatures of a variety of environmental and agricultural products from different origins, providing information about food authenticity and climate changes effect on plant physiology.
Elements of abstract harmonic analysis
Bachman, George
2013-01-01
Elements of Abstract Harmonic Analysis provides an introduction to the fundamental concepts and basic theorems of abstract harmonic analysis. In order to give a reasonably complete and self-contained introduction to the subject, most of the proofs have been presented in great detail thereby making the development understandable to a very wide audience. Exercises have been supplied at the end of each chapter. Some of these are meant to extend the theory slightly while others should serve to test the reader's understanding of the material presented. The first chapter and part of the second give
Mazur Czerwiec, Zdzislaw; Campos Amezcua, Alfonso; Campos Amezcua, Rafael [Instituto de Investigaciones Electricas, Cuernavaca, Morelos (Mexico)
2010-07-01
The analysis of erosion by solid particles is presented of different elements of the flow channel of the steam turbines that operate in Mexico: nozzles, stop valves, blade bosses, labyrinth seals and rotor disc; using tools of of Computational Fluid Dynamics (CFD). In these main elements of turbines a strong problem of erosion was registered that threatens the reliable operation of the turbines, its availability and its optimal yield. With base on the results of the numerical analyses, the design modifications of the different elements were developed from the flow channel of the steam turbines, in order to reduce the erosion and thus diminishing the energy losses and increasing the steam turbine efficiency. This work presents the main benefits that the Thermoelectric Power Plants obtain with the reduction of the erosion by solid particles that affect the critical components of steam turbines: extension of the period between maintenance, replacement of components, reduction of operation and maintenance costs of the turbines, and extension of the useful life of the main components. [Spanish] Se presenta el analisis de erosion por particulas solidas de diferentes elementos del canal de flujo de las turbinas de vapor que operan en Mexico: toberas, valvula de paro, tetones de los alabes, sellos de laberinto y disco del rotor; utilizando herramientas de Dinamica de Fluidos Computacional (DFC). En estos elementos principales de turbinas se registro un fuerte problema de erosion que amenaza la operacion confiable de las turbinas, su disponibilidad y su rendimiento optimo. Con base en los resultados de los analisis numericos, se desarrollaron las modificaciones de diseno de los diferentes elementos del canal de flujo de las turbinas de vapor, con el proposito de reducir la erosion y asi, disminuir las perdidas de energia e incrementar el rendimiento de las turbinas de vapor. Este trabajo presenta los principales beneficios que obtienen las Centrales Termoelectricas con la
Aguirre-Ramirez, G.; Oden, J. T.
1969-01-01
Finite element method applied to heat conduction in solids with temperature dependent thermal conductivity, using nonlinear constitutive equation for heat ABCDEFGHIABCDEFGHIABCDEFGHIABCDEFGHIABCDEFGHIABCDEFGHIABCDEFGHIABCDEFGHIABCDEFGHIABCDEFGHIABCDEFGHIABCDEFGH
Downhole elemental analysis with LIBS
Moreschini, P.; Zacny, K.; Rickman, D.
2011-12-01
In this paper we discuss a novel instrument, currently under development at Honeybee Robotics with SBIR funding from NASA. The device is designed to characterize elemental composition as a function of depth in non-terrestrial geological formations. The instrument consists of a miniaturized LIBS analyzer integrated in a 2" diameter drill string. While the drill provides subsurface access, the LIBS analyzer provides information on the elemental composition of the borehole wall. This instrument has a variety of space applications ranging from exploration of the Moon for which it was originally designed, to Mars, as well as a variety of terrestrial applications. Subsurface analysis is usually performed by sample acquisition through a drill or excavator, followed by sample preparation and subsequent sample presentation to an instrument or suite of instruments. An alternative approach consisting in bringing a miniaturized version of the instrument to the sample has many advantages over the traditional methodology, as it allows faster response, reduced probability of cross-contamination and a simplification in the sampling mechanisms. LIBS functions by focusing a high energy laser on a material inducing a plasma consisting of a small fraction of the material under analysis. Optical emission from the plasma, analyzed by a spectrometer, can be used to determine elemental composition. A triangulation sensor located in the sensor head determines the distance of the sensor from the borehole wall. An actuator modifies the position of the sensor accordingly, in order to compensate for changes due to the profile of the borehole walls. This is necessary because LIBS measurements are negatively affected by changes in the relative position of the focus of the laser with respect to the position of the sample (commonly referred to as the "lens to sample distance"). Profiling the borehole is done by adjusting the position of the sensor with a vertical stage; a second actuator at the
王利民
2010-01-01
首先使用Solidworks对全自动塑杯灌装封口机的各个模块进行三维实体建模,然后以该封口机左侧机体模块为研究对象,使用SolidWorks的COSMOSWorks有限元分析插件对其进行有限元分析,得出应力、应变、位移、安全系数图解,针对图解的结果,提出相应的改进措施,目的在于最大限度地缩短全自动塑杯灌装封口机的设计周期,降低测试成本,提高产品质量,加大利润空间,并为进一步进行优化设计提供了有效的途径.
Correct use of Membrane Elements in Structural Analysis
Rothman Timothy
2016-01-01
Full Text Available Structural analysis of consumer electronic devices such as phones and tablets involves Finite Element Analysis (FEA. Dynamic loading conditions such as device dropping and bending dictate accurate FEA models to reduce design risk in many areas. The solid elements typically used in structural analysis do not have integration points on the surface. The outer surface is of most interest because that is where the cracks start. Analysts employ a post processing trick through using membranes to bring accurate stress/strain results to the surface. This paper explains numerical issues with implementation of membranes and recommends a methodology for accurate structural analysis.
阿肯江·托呼提; 亓国庆
2008-01-01
采用大型有限元软件ANSYS10.0中的Solid65和Solid15两种单元类型,对单调水平荷载下素夯土墙抗震性能进行了计算分析.计算结果和试验结果进行比较,从中选择合适的单元类型和破坏准则.为进一步计算分析木柱梁-土坯组合墙体的抗震性能奠定建模基础.
Stock flow diagram analysis on solid waste management in Malaysia
Zulkipli, Faridah; Nopiah, Zulkifli Mohd; Basri, Noor Ezlin Ahmad; Kie, Cheng Jack
2016-10-01
The effectiveness on solid waste management is a major importance to societies. Numerous generation of solid waste from our daily activities has risked for our communities. These due to rapid population grow and advance in economic development. Moreover, the complexity of solid waste management is inherently involved large scale, diverse and element of uncertainties that must assist stakeholders with deviating objectives. In this paper, we proposed a system dynamics simulation by developing a stock flow diagram to illustrate the solid waste generation process and waste recycle process. The analysis highlights the impact on increasing the number of population toward the amount of solid waste generated and the amount of recycled waste. The results show an increment in the number of population as well as the amount of recycled waste will decrease the amount of waste generated. It is positively represent the achievement of government aim to minimize the amount of waste to be disposed by year 2020.
Vibration Analysis of Plates by MLS-Element Method
Zhou, L.; Xiang, Y.
2010-05-01
This paper presents a novel numerical method, the moving least square element (MLS-element) method for the free vibration analysis of plates based on the Mindlin shear deformable plate theory. In the MLS-element method, a plate can be first divided into multiple elements which are connected through selected nodal points on the interfaces of the elements. An element can be of any shape and the size of the element varies dependent on the problem at hand. The shape functions of the element for the transverse displacement and the rotations are derived based on the MLS interpolation technique. The convergence and accuracy of the method can be controlled by either increasing the number of elements or by increasing the number of MLS interpolation points within elements. Two selected examples for vibration of a simply supported square Mindlin plate and a clamped L-shaped Mindlin plate are studied to illustrate the versatility and accuracy of the proposed method. It shows that the proposed method is highly accurate and flexible for the vibration analysis of plate problems. The method can be further developed to bridge the existing meshless method and the powerful finite element method in dealing with various engineering computational problems, such as large deformation and crack propagation in solid mechanics.
Proximate and elemental analysis of infant formula.
Tanner, J T
1982-11-01
The Nutrient Surveillance Branch has been conducting a survey of infant formula products for Fiscal Year 1981. Each product has been carefully analyzed and the results compared to the label declaration and the minimum-maximum limits specified by the American Academy of Pediatrics' Committee on Nutrition (CON/AAP). Proximate and elemental analyses were made. Protein, fat, ash, and total solids (moisture) were determined by AOAC methods. Osmolality, density, and fatty acids (linoleic) were also determined. Carbohydrates were calculated by difference and caloric content was calculated by using the general Atwater factors. Elemental analysis for Ca, P, Mg, Fe, Zn, Cu, Mn, Na, and K were performed by induction coupled plasma absorption spectroscopy. Chloride was assayed by potentiometric titration with AgNO3. A summary of the findings from the infant formula survey have been compared with CON/AAP recommendations. In general, there were only a few exceptions where the label claims and the CON/AAP requirements were not met. However, in none of these cases was the difference considered to be of public health significance.
Solid waste burial grounds interim safety analysis
Saito, G.H.
1994-10-01
This Interim Safety Analysis document supports the authorization basis for the interim operation and restrictions on interim operations for the near-surface land disposal of solid waste in the Solid Waste Burial Grounds. The Solid Waste Burial Grounds Interim Safety Basis supports the upgrade progress for the safety analysis report and the technical safety requirements for the operations in the Solid Waste Burial Grounds. Accident safety analysis scenarios have been analyzed based on the significant events identified in the preliminary hazards analysis. The interim safety analysis provides an evaluation of the operations in the Solid Waste Burial Grounds to determine if the radiological and hazardous material exposures will be acceptable from an overall health and safety standpoint to the worker, the onsite personnel, the public, and the environment.
International Symposium on Boundary Element Methods : Advances in Solid and Fluid Mechanics
Tseng, Kadin
1990-01-01
The Boundary Element Method (BEM) has become established as an effective tool for the solutions of problems in engineering science. The salient features of the BEM have been well documented in the open literature and therefore will not be elaborated here. The BEM research has progressed rapidly, especially in the past decade and continues to evolve worldwide. This Symposium was organized to provide an international forum for presentation of current research in BEM for linear and nonlinear problems in solid and fluid mechanics and related areas. To this end, papers on the following topics were included: rotary wing aerodynamics, unsteady aerodynamics, design and optimization, elasticity, elasto dynamics and elastoplasticity, fracture mechanics, acoustics, diffusion and wave motion, thermal analysis, mathematical aspects and boundary/finite element coupled methods. A special session was devoted to parallel/vector supercomputing with emphasis on mas sive parallelism. This Symposium was sponsored by United ...
Three dimensional mathematical model of tooth for finite element analysis
Puškar Tatjana
2010-01-01
Full Text Available Introduction. The mathematical model of the abutment tooth is the starting point of the finite element analysis of stress and deformation of dental structures. The simplest and easiest way is to form a model according to the literature data of dimensions and morphological characteristics of teeth. Our method is based on forming 3D models using standard geometrical forms (objects in programmes for solid modeling. Objective. Forming the mathematical model of abutment of the second upper premolar for finite element analysis of stress and deformation of dental structures. Methods. The abutment tooth has a form of a complex geometric object. It is suitable for modeling in programs for solid modeling SolidWorks. After analyzing the literature data about the morphological characteristics of teeth, we started the modeling dividing the tooth (complex geometric body into simple geometric bodies (cylinder, cone, pyramid,.... Connecting simple geometric bodies together or substricting bodies from the basic body, we formed complex geometric body, tooth. The model is then transferred into Abaqus, a computational programme for finite element analysis. Transferring the data was done by standard file format for transferring 3D models ACIS SAT. Results. Using the programme for solid modeling SolidWorks, we developed three models of abutment of the second maxillary premolar: the model of the intact abutment, the model of the endodontically treated tooth with two remaining cavity walls and the model of the endodontically treated tooth with two remaining walls and inserted post. Conclusion Mathematical models of the abutment made according to the literature data are very similar with the real abutment and the simplifications are minimal. These models enable calculations of stress and deformation of the dental structures. The finite element analysis provides useful information in understanding biomechanical problems and gives guidance for clinical research.
[Three dimensional mathematical model of tooth for finite element analysis].
Puskar, Tatjana; Vasiljević, Darko; Marković, Dubravka; Jevremović, Danimir; Pantelić, Dejan; Savić-Sević, Svetlana; Murić, Branka
2010-01-01
The mathematical model of the abutment tooth is the starting point of the finite element analysis of stress and deformation of dental structures. The simplest and easiest way is to form a model according to the literature data of dimensions and morphological characteristics of teeth. Our method is based on forming 3D models using standard geometrical forms (objects) in programmes for solid modeling. Forming the mathematical model of abutment of the second upper premolar for finite element analysis of stress and deformation of dental structures. The abutment tooth has a form of a complex geometric object. It is suitable for modeling in programs for solid modeling SolidWorks. After analysing the literature data about the morphological characteristics of teeth, we started the modeling dividing the tooth (complex geometric body) into simple geometric bodies (cylinder, cone, pyramid,...). Connecting simple geometric bodies together or substricting bodies from the basic body, we formed complex geometric body, tooth. The model is then transferred into Abaqus, a computational programme for finite element analysis. Transferring the data was done by standard file format for transferring 3D models ACIS SAT. Using the programme for solid modeling SolidWorks, we developed three models of abutment of the second maxillary premolar: the model of the intact abutment, the model of the endodontically treated tooth with two remaining cavity walls and the model of the endodontically treated tooth with two remaining walls and inserted post. Mathematical models of the abutment made according to the literature data are very similar with the real abutment and the simplifications are minimal. These models enable calculations of stress and deformation of the dental structures. The finite element analysis provides useful information in understanding biomechanical problems and gives guidance for clinical research.
FINITE ELEMENT ANALYSIS OF STRUCTURES
PECINGINA OLIMPIA-MIOARA
2015-05-01
Full Text Available The application of finite element method is analytical when solutions can not be applied for deeper study analyzes static, dynamic or other types of requirements in different points of the structures .In practice it is necessary to know the behavior of the structure or certain parts components of the machine under the influence of certain factors static and dynamic . The application of finite element in the optimization of components leads to economic growth , to increase reliability and durability organs studied, thus the machine itself.
Why do probabilistic finite element analysis ?
Thacker, B H
2008-01-01
The intention of this book is to provide an introduction to performing probabilistic finite element analysis. As a short guideline, the objective is to inform the reader of the use, benefits and issues associated with performing probabilistic finite element analysis without excessive theory or mathematical detail.
Elements of stock market analysis
Suciu, T.
2013-01-01
The paper represents a starting point in the presentation of the two types of stock/market analysis: the fundamental analysis and the technical analysis. The fundamental analysis consist in the assessment of the financial and economic status of the company together with the context and macroeconomic environment where it activates. The technical analysis deals with the demand and supply of securities and the evolution of their trend on the market, using a range of graphics and charts to il...
A method for making an element with a solid electrolyte
Takakhasi, K.; Ivaki, T.
1983-08-11
A mixture of an active substance and a binder is applied to the plate which serves as the base for the electrode. The compound is dried. A layer of solid electrolyte, which contains a mixture of a substance which contains crystallization water, of the Zn3(P04)2 with 4H20 type, and a salt which dissolves in this water, is applied to the obtained electrode. A layer which contains the active mass of the electrode P with a binder is applied after curing and drying. The cells are collected into a miniature battery used in electronic equipment.
PARTITION OF UNITY FINITE ELEMENT METHOD FOR SHORT WAVE PROPAGATION IN SOLIDS
LI Xi-kui; ZHOU Hao-yang
2005-01-01
A partition of unity finite element method for numerical simulation of short wave propagation in solids is presented. The finite element spaces were constructed by multiplying the standard isoparametric finite element shape functions, which form a partition of unity, with the local subspaces defined on the corresponding shape functions, which include a priori knowledge about the wave motion equation in trial spaces and approximately reproduce the highly oscillatory properties within a single element. Numerical examples demonstrate the performance of the proposed partition of unity finite element in both computational accuracy and efficiency.
Elements of stock market analysis
Suciu, T.
2013-12-01
Full Text Available The paper represents a starting point in the presentation of the two types of stock/market analysis: the fundamental analysis and the technical analysis. The fundamental analysis consist in the assessment of the financial and economic status of the company together with the context and macroeconomic environment where it activates. The technical analysis deals with the demand and supply of securities and the evolution of their trend on the market, using a range of graphics and charts to illustrate the market tendencies for the quick identification of the best moments to buy or sell.
Solid-surface luminescence analysis
Hurtubise, R.J.
1991-01-01
We have characterized several interactions that are very important in solid-matrix luminescence. With silica gel chromatoplates and filter paper, simple equations were derived for calculating the individual contributions to the percent decrease in luminescence due to either moisture or to a quenching gas. For sodium acetate as a solid matrix and p-aminobenzoate as a model compound, it was concluded that p-aminobenzoate was incorporated into the crystal structure of sodium acetate, and the triplet energy was lost be skeletal vibrations in sodium acetate. Also, with the same system is was shown that p-aminobenzoate did not undergo rotational relaxation, and thus rotational processes did not contribute to the deactivation of the triplet state. Several results were obtained from model compounds adsorbed on filter paper under different temperature and humidity conditions and with a variety of heavy atoms present. Fundamental photophysical equations were used in calculating several basic parameters that revealed information on rate processes and how the absorbed energy was distributed in an adsorbed lumiphor. The most important advancement with filter paper was the development of equations that relate phosphorescence parameters of adsorbed phosphors to the Young's modulus of filter paper. These equations are based on a fundamental theory that relates the hydrogen-bonding network of paper to the modulus of paper.
Solid-matrix luminescence analysis
Hurtubise, R.J.
1993-01-15
Several interactions with lumiphors adsorbed on filter paper were elucidated from experiments with moisture, modulus and heavy-atom salts. The data were interpreted using static and dynamic quenching models, heavy-atom theory, and a theory related to the modulus of paper. With cyclodextrin-salt matrices, it was shown that 10% [alpha]-cyclodextrin/NaCl was very effective for obtaining strong room-temperature fluorescence and moderate room-temperature phosphorescence from adsorbed stereoisomeric tetrols. Extensive photophysical information was obtained for the four tetrols on 10% [alpha]-cyclodextrin/NaCl. The photophysical information acquired was used to develop a method for characterizing two of the tetrols. Work with model compounds adsorbed on deuterated sodium acetate showed that C-H vibrations in the undeuterated sodium acetate were not responsible for the deactivation of the excited triplet state in the model phosphors investigated. A considerable amount of solution luminescence and solid-matrix luminescence data were compared. The most important finding was that in several cases the room-temperature solid-matrix luminescence quantum yields were greater than the solution low-temperature quantum yield values.
Analysis of composite structural elements
A. Baier
2010-12-01
Full Text Available Purpose: The themes of the study are composite structural components. For this purpose have been designed and built several research positions.Design/methodology/approach: Using different structural materials to build new device components requires multiple tests of the components. Research posts were designed in the advanced graphical program CAx Siemens NX 7.5. Analysed samples were made from the glass fibre, aramid and carbon of various weights. Due to the specific use of composite materials it focuses on the elements in the form of plates and flat bars. For the examination of experimental strain gauge technique was used bead, the force sensor and displacement sensor. The experimental methods were compared with computer simulation using the FEM.Findings: The aim of this study was to determine the basic material constants and a comparison of the experimental method and the method of computer simulation.Research limitations/implications: Change the number of layers and how to connect the laminate with the steel plate changes mechanical properties of the structural component.Practical implications: The ultimate result will be knowledge on the different forms of laminates, such as material properties, the stresses in all layers, strain and comparing the results obtained by two methods.Originality/value: The expected outcome of the study will be the composition and method of joining composite laminate with a steel plate to the possible application in the repair and construction of structural elements of freight wagons.
METHODOLOGICAL ELEMENTS OF SITUATIONAL ANALYSIS
Tetyana KOVALCHUK
2016-01-01
The article deals with the investigation of theoretical and methodological principles of situational analysis. The necessity of situational analysis is proved in modern conditions. The notion “situational analysis” is determined. We have concluded that situational analysis is a continuous system study which purpose is to identify dangerous situation signs, to evaluate comprehensively such signs influenced by a system of objective and subjective factors, to search for motivated targeted action...
Rosende, María; Miró, Manuel; Cerdà, Víctor
2010-01-18
Dynamic flow-through extraction/fractionation methods have recently drawn much attention as appealing alternatives to the batchwise steady-state counterparts for the evaluation of environmentally available pools of potentially hazardous trace elements in solid matrices. The most critical weakness of flow-based column approaches lies in the small amount of solid that can be handled, whereby their applicability has been merely limited to date to the extraction of trace elements in highly homogeneous solid substrates; otherwise the representativeness of the test portion might not be assured. To tackle this limitation, we have devised an automated flow-through system incorporating a specially designed extraction column with a large volume capacity, wherein up to 2 g of solid sample could be handled without undue backpressure. The assembled flow setup was exploited for fast screening of potentially hazardous trace elements (namely, Cd, Cr, Cu, Pb, and Zn) in highly inhomogeneous municipal solid waste incineration (MSWI) bottom ashes. The pools of readily mobilizable metal forms were ascertained using the Toxicity Characteristic Leaching Procedure (TCLP) based on the usage of 0.1 mol L(-1) CH(3)COOH as leachant and analysis of extracts by inductively coupled optical emission spectrometry. The application of a two-level full factorial (screening) design revealed that the effect of sample fluidization primarily but other experimental factors such as the solid to liquid ratio and extractant flow rate significantly influenced the leachability of given elements in raw bottom ashes at the 0.05 significance level. The analytical performance of the novel flow-based method capitalized on fluidized-bed extraction was evaluated in terms of accuracy, through the use of mass balance validation, reproducibility and operational time as compared to batchwise extraction and earlier flow injection/sequential injection microcolum-based leaching tests.
Study of solid solution strengthening of alloying element with phase structure factors
无
2003-01-01
Using the empirical electron theory of solids and molecules (EET), the phase structure factors, nA and nB, of the carbon-containing structural units with mass fraction of carbon (wC) below 0.8% and the mono-alloy structural units with wC at 0.2% in austenite and martensite are calculated. The solid solution strengthening brought by C-containing interstitial solid solution and alloy-substitutional solid solution in γ-Fe and α-Fe is discussed at electron structural level. The coefficient (s) of solid solution strengthening is advanced according to the bonding force between atoms. The study shows that when the criterion is applied to the carbonaceous or alloying element-containing solid solution the results of calculation will coincide with the experimental result very well.
Finite Dynamic Elements and Modal Analysis
N.J. Fergusson
1993-01-01
Full Text Available A general modal analysis scheme is derived for forced response that makes use of high accuracy modes computed by the dynamic element method. The new procedure differs from the usual modal analysis in that the modes are obtained from a power series expansion for the dynamic stiffness matrix that includes an extra dynamic correction term in addition to the static stiffness matrix and the consistent mass matrix based on static displacement. A cantilevered beam example is used to demonstrate the relative accuracies of the dynamic element and the traditional finite element methods.
EXTRUSION FORMING OF A DOUBLE BASE SOLID ROCKET PROPELLANT BY FINITE ELEMENT METHOD
Barış KALAYCIOĞLU
2007-01-01
Full Text Available In this study, three dimensional modelling of extrusion forming of a double base solid rocket propellant is performed on Ansys® finite element simulation package. For the purpose of initial model construction and later comparisons with elastoviscoplastik model, the solid propellant is assumed to obey the elastic-plastic material response during the direct extrusion process. Taking into account the contact surface behavior with Coulomb friction and geometric and material nonlinearities, an incremental large large strain solution methodology has been adapted in the simulation. The hydrostatic pressure, stress, strain, and displacement values during extrusion of the solid rocket propellant are obtained from the simulation.
Accelerated exploration of multi-principal element alloys with solid solution phases
Senkov, O. N.; Miller, J. D.; Miracle, D. B.; Woodward, C.
2015-03-01
Recent multi-principal element, high entropy alloy (HEA) development strategies vastly expand the number of candidate alloy systems, but also pose a new challenge—how to rapidly screen thousands of candidate alloy systems for targeted properties. Here we develop a new approach to rapidly assess structural metals by combining calculated phase diagrams with simple rules based on the phases present, their transformation temperatures and useful microstructures. We evaluate over 130,000 alloy systems, identifying promising compositions for more time-intensive experimental studies. We find the surprising result that solid solution alloys become less likely as the number of alloy elements increases. This contradicts the major premise of HEAs—that increased configurational entropy increases the stability of disordered solid solution phases. As the number of elements increases, the configurational entropy rises slowly while the probability of at least one pair of elements favouring formation of intermetallic compounds increases more rapidly, explaining this apparent contradiction.
Accelerated exploration of multi-principal element alloys with solid solution phases.
Senkov, O N; Miller, J D; Miracle, D B; Woodward, C
2015-03-05
Recent multi-principal element, high entropy alloy (HEA) development strategies vastly expand the number of candidate alloy systems, but also pose a new challenge--how to rapidly screen thousands of candidate alloy systems for targeted properties. Here we develop a new approach to rapidly assess structural metals by combining calculated phase diagrams with simple rules based on the phases present, their transformation temperatures and useful microstructures. We evaluate over 130,000 alloy systems, identifying promising compositions for more time-intensive experimental studies. We find the surprising result that solid solution alloys become less likely as the number of alloy elements increases. This contradicts the major premise of HEAs--that increased configurational entropy increases the stability of disordered solid solution phases. As the number of elements increases, the configurational entropy rises slowly while the probability of at least one pair of elements favouring formation of intermetallic compounds increases more rapidly, explaining this apparent contradiction.
Solid rocket booster internal flow analysis by highly accurate adaptive computational methods
Huang, C. Y.; Tworzydlo, W.; Oden, J. T.; Bass, J. M.; Cullen, C.; Vadaketh, S.
1991-01-01
The primary objective of this project was to develop an adaptive finite element flow solver for simulating internal flows in the solid rocket booster. Described here is a unique flow simulator code for analyzing highly complex flow phenomena in the solid rocket booster. New methodologies and features incorporated into this analysis tool are described.
Finite elements for analysis and design
Akin, J E; Davenport, J H
1994-01-01
The finite element method (FEM) is an analysis tool for problem-solving used throughout applied mathematics, engineering, and scientific computing. Finite Elements for Analysis and Design provides a thoroughlyrevised and up-to-date account of this important tool and its numerous applications, with added emphasis on basic theory. Numerous worked examples are included to illustrate the material.Key Features* Akin clearly explains the FEM, a numerical analysis tool for problem-solving throughout applied mathematics, engineering and scientific computing* Basic theory has bee
Finite element analysis of optical waveguides
Mabaya, N.; Lagasse, P. E.; Vandenbulcke, P.
1981-06-01
Several finite element programs for the computation of the guided modes of optical waveguides are presented. The advantages and limitations of a very general program for the analysis of anisotropic guides are presented. A possible solution to the problem of the spurious numerical modes, encountered when calculating higher order modes, is proposed. For isotropic waveguides, it is shown that both EH- and HE-type modes can be very accurately approximated by two different scalar finite element programs. Finally, a boundary perturbation method is outlined that makes it possible to calculate the attenuation coefficient of leaky modes in single material guides, starting from a finite element calculation.
Electrical machine analysis using finite elements
Bianchi, Nicola
2005-01-01
OUTLINE OF ELECTROMAGNETIC FIELDSVector AnalysisElectromagnetic FieldsFundamental Equations SummaryReferencesBASIC PRINCIPLES OF FINITE ELEMENT METHODSIntroductionField Problems with Boundary ConditionsClassical Method for the Field Problem SolutionThe Classical Residual Method (Galerkin's Method)The Classical Variational Method (Rayleigh-Ritz's Method)The Finite Element MethodReferencesAPPLICATIONS OF THE FINITE ELEMENT METHOD TO TWO-DIMENSIONAL FIELDSIntroductionLinear Interpolation of the Function fApplication of the Variational MethodSimple Descriptions of Electromagnetic FieldsAppendix: I
Arslan, Z; Paulson, A J
2002-04-01
The aragonite deposits within the ear bones (otoliths) of teleost fish retain a chemical signal reflecting the life history of fish (similar to rings of trees) and the nature of fish habitats. Otoliths dissolved in acid solutions contain high concentrations of calcium and a variety of proteins. Elimination of matrix salts and organic interferences during preconcentration is essential for accurate determination of trace elements in otolith solutions by inductively coupled plasma-quadrupole mass spectrometry. An iminodiacetate-based chelating resin (Toyopearl AF-Chelate 650 M) has been used for on-line preconcentration and matrix separation for the determination of 31 transition and rare elements. Successful preconcentration of the elements was achieved at pH 5 by on-line buffering, except Mn which required pH 8.8. Sample solutions were loaded on to the column for 1 min at 3.2 mL min(-1), and then eluted directly into the mass spectrometer with 4% v/v nitric acid. This procedure enabled up to 25-fold preconcentration with successful removal of the calcium matrix. The effect of heat-assisted oxidation with concentrated nitric acid was investigated to eliminate the organic matrix. It was found that heating to dryness after dissolution and further mineralization with the acid significantly improved the retention of the transition elements. The method was validated by analysis of a certified reference material produced from saggittal otoliths of emperor snapper ( Lutjanus sebae), and then applied to the determination of trace metal concentrations in juvenile bluefin tuna ( Thunnus thynnus) from the Western Pacific Ocean.
Arslan, Z.; Paulson, A.J. [National Oceanic and Atmospheric Administration (NOAA), Northeast Fisheries Science Center (NFSC), James J. Howard Marine Sciences Laboratory, Highlands, NJ (United States)
2002-04-01
The aragonite deposits within the ear bones (otoliths) of teleost fish retain a chemical signal reflecting the life history of fish (similar to rings of trees) and the nature of fish habitats. Otoliths dissolved in acid solutions contain high concentrations of calcium and a variety of proteins. Elimination of matrix salts and organic interferences during preconcentration is essential for accurate determination of trace elements in otolith solutions by inductively coupled plasma-quadrupole mass spectrometry. An iminodiacetate-based chelating resin (Toyopearl AF-Chelate 650 M) has been used for on-line preconcentration and matrix separation for the determination of 31 transition and rare elements. Successful preconcentration of the elements was achieved at pH 5 by on-line buffering, except Mn which required pH 8.8. Sample solutions were loaded on to the column for 1 min at 3.2 mL min{sup -1}, and then eluted directly into the mass spectrometer with 4% v/v nitric acid. This procedure enabled up to 25-fold preconcentration with successful removal of the calcium matrix. The effect of heat-assisted oxidation with concentrated nitric acid was investigated to eliminate the organic matrix. It was found that heating to dryness after dissolution and further mineralization with the acid significantly improved the retention of the transition elements. The method was validated by analysis of a certified reference material produced from saggittal otoliths of emperor snapper (Lutjanus sebae), and then applied to the determination of trace metal concentrations in juvenile bluefin tuna (Thunnus thynnus) from the Western Pacific Ocean. (orig.)
Druzhinin A. A.
2014-12-01
Full Text Available The paper presents the study results of electrical properties of polycrystalline silicon films in silicon-on-insulator structures and Si whiskers in the temperature range of 4,2—70 K obtained by impedance measurements in the frequency range from 10 Hz to 250 kHz and the possibility of their use in solid-state electronics, functioning at cryogenic temperatures. Characteristics of samples obtained with impedance measurements allow to predict certain specifications of reactive elements of solid state electronics based on polycrystalline and single crystalline silicon, operable at low temperatures. Using the established dependencies, separate elements in the form of solid-state electronics capacitive and inductive elements as well as a combined system in an oscillatory circuit, operable at cryogenic temperatures, have been suggested. The features of developed system depend on the structure of samples and their doping level, which allows to change the required parameters of the elements of solid state electronics in a wide range.
Toward an accurate description of solid-state properties of superheavy elements
Schwerdtfeger Peter
2016-01-01
Full Text Available In the last two decades cold and hot fusion experiments lead to the production of new elements for the Periodic Table up to nuclear charge 118. Recent developments in relativistic quantum theory have made it possible to obtain accurate electronic properties for the trans-actinide elements with the aim to predict their potential chemical and physical behaviour. Here we report on first results of solid-state calculations for Og (element 118 to support future atom-at-a-time gas-phase adsorption experiments on surfaces such as gold or quartz.
Fourier analysis for rotating-element ellipsometers.
Cho, Yong Jai; Chegal, Won; Cho, Hyun Mo
2011-01-15
We introduce a Fourier analysis of the waveform of periodic light-irradiance variation to capture Fourier coefficients for multichannel rotating-element ellipsometers. In this analysis, the Fourier coefficients for a sample are obtained using a discrete Fourier transform on the exposures. The analysis gives a generic function that encompasses the discrete Fourier transform or the Hadamard transform, depending on the specific conditions. Unlike the Hadamard transform, a well-known data acquisition method that is used only for conventional multichannel rotating-element ellipsometers with line arrays with specific readout-mode timing, this Fourier analysis is applicable to various line arrays with either nonoverlap or overlap readout-mode timing. To assess the effects of the novel Fourier analysis, the Fourier coefficients for a sample were measured with a custom-built rotating-polarizer ellipsometer, using this Fourier analysis with various numbers of scans, integration times, and rotational speeds of the polarizer.
Revolution in Orthodontics: Finite element analysis
Singh, Johar Rajvinder; Kambalyal, Prabhuraj; Jain, Megha; Khandelwal, Piyush
2016-01-01
Engineering has not only developed in the field of medicine but has also become quite established in the field of dentistry, especially Orthodontics. Finite element analysis (FEA) is a computational procedure to calculate the stress in an element, which performs a model solution. This structural analysis allows the determination of stress resulting from external force, pressure, thermal change, and other factors. This method is extremely useful for indicating mechanical aspects of biomaterials and human tissues that can hardly be measured in vivo. The results obtained can then be studied using visualization software within the finite element method (FEM) to view a variety of parameters, and to fully identify implications of the analysis. This is a review to show the applications of FEM in Orthodontics. It is extremely important to verify what the purpose of the study is in order to correctly apply FEM. PMID:27114948
Nonlinear Finite Element Analysis of Ocean Cables
Nam-Il KIM; Sang-Soo JEON; Moon-Young KIM
2004-01-01
This study has focused on developing numerical procedures for the dynamic nonlinear analysis of cable structures subjected to wave forces and ground motions in the ocean. A geometrically nonlinear finite element procedure using the isoparametric curved cable element based on the Lagrangian formulation is briefly summarized. A simple and accurate method to determine the initial equilibrium state of cable systems associated with self-weights, buoyancy and the motion of end points is presented using the load incremental method combined with penalty method. Also the Newmark method is used for dynamic nonlinear analysis of ocean cables. Numerical examples are presented to validate the present numerical method.
Experimental Finite Element Approach for Stress Analysis
Ahmet Erklig
2014-01-01
Full Text Available This study aims to determining the strain gauge location points in the problems of stress concentration, and it includes both experimental and numerical results. Strain gauges were proposed to be positioned to corresponding locations on beam and blocks to related node of elements of finite element models. Linear and nonlinear cases were studied. Cantilever beam problem was selected as the linear case to approve the approach and conforming contact problem was selected as the nonlinear case. An identical mesh structure was prepared for the finite element and the experimental models. The finite element analysis was carried out with ANSYS. It was shown that the results of the experimental and the numerical studies were in good agreement.
Sauer, Roger A; Corbett, Callum J
2012-01-01
A geometrically exact membrane formulation is presented that is based on curvilinear coordinates and isogeometric finite elements, and is suitable for both solid and liquid membranes. The curvilinear coordinate system is used to describe both the theory and the finite element equations of the membrane. In the latter case this avoids the use of local cartesian coordinates at the element level. Consequently, no transformation of derivatives is required. The formulation considers a split of the in-plane and out-of-plane membrane contributions, which allows the construction of a stable formulation for liquid membranes with constant surface tension. The proposed membrane formulation is general, and accounts for dead and live loading, as well as enclosed volume, area, and contact constraints. The new formulation is illustrated by several challenging examples, considering linear and quadratic Lagrange elements, as well as isogeometric elements based on quadratic NURBS and cubic T-splines. It is seen that the isogeom...
Constructal optimization for a solid-gas reactor based on triangular element
2008-01-01
Entropy generation minimization for heat and mass transfer process in a solid-gas reactor is carried out based on constructal theory by using triangular elemental area. The aspect ratio of the triangular elemental area is optimized under constraint conditions. A number of optimal triangular elements are assembled to a new large rectangular area, which is optimised again. The procedure is repeated until the control-volume is covered, and the complete analytical results are obtained. The effects of some parameters on minimum entropy generation are analysed by nu-merical examples. The results show that smaller entropy generation can be ob-tained when the optimization for a given volume is carried out on the basis of tri-angular elements than those obtained on the basis of rectangular elements.
FINITE ELEMENT ANALYSIS FOR PERIFLEX COUPLINGS
URDEA Mihaela
2015-06-01
Full Text Available The Periflex shaft couplings with rubber sleeve have a hig elasticity and link two shafts in diesel-engine and electric drives. They are simple from the point of view of construction, easily mounted and dismounted. The main goal of this paper is to present a finite element analysis for the Periflex coupling using the Generative Structural Analysis from CATIA software package. This paper presents important information about how to prepare an assembly for creating a static analysis case and also the important steps for developing a finite element analysis. It is very important that the analysis model should have the same behavior as the real, also the loading model. The results are images corresponding to Von Mises Stresses and Translational Displacement magnitude.
Interval Finite Element Analysis of Wing Flutter
Wang Xiaojun; Qiu Zhiping
2008-01-01
The influences of uncertainties in structural parameters on the flutter speed of wing are studied. On the basis of the deterministic flutter analysis model of wing, the uncertainties in structural parameters are considered and described by interval numbers. By virtue of first-order Taylor series expansion, the lower and upper bound curves of the transient decay rate coefficient versus wind velocity are given. So the interval estimation of the flutter critical wind speed of wing can be obtained, which is more reasonable than the point esti- mation obtained by the deterministic flutter analysis and provides the basis for the further non-probabilistic interval reliability analysis of wing flutter. The flow chart for interval finite element model of flutter analysis of wing is given. The proposed interval finite element model and the stochastic finite element model for wing flutter analysis are compared by the examples of a three degrees of freedorn airfoil and fuselage and a 15° swepthack wing, and the results have shown the effectiveness and feasibility of the presented model. The prominent advantage of the proposed interval finite element model is that only the bounds of uncertain parameters axe required, and the probabilistic distribution densities or other statistical characteristics are not needed.
Sun, Zhidan; Bernacki, Marc; Logé, Roland; Gu, Guochao
2017-09-01
In this work, a level-set based finite element method was used to numerically evaluate the mechanical behavior in a small deformation range of semi-solid materials with different microstructure configurations. For this purpose, a finite element model of the semi-solid phase was built based on Voronoï diagram. Interfaces between the solid and the liquid phases were implicitly described by level-set functions coupled to an anisotropic meshing technique. The liquid phase was considered as a Newtonian fluid, whereas the behavior of the solid phase was described by a viscoplastic law. Simulations were performed to study the effect of different parameters such as solid phase fraction and solid bridging. Results show that the macroscopic mechanical behavior of semi-solid material strongly depends on the solid fraction and the local microstructure which play important roles in the formation of hot tearing. These results could provide valuable information for the processing of semi-solid materials.
Latest Trends in Finite Element Analysis
L. S. Madhav
1996-01-01
Full Text Available This paper highlights the advances in computer graphics and the computational power of the processors which have promoted a method of analysis, applicable to almost all the fields of engineering. The advantages of the computers have been judiciously used in the design of algorithms, based on the principles of finite difference, finite element, boundary element, etc., intended for the analysis of engineering components. The concept of finite element method which has been generalised with the availability of commercial software, is also reviewed with a special emphasis on the future trends. The modelling and visualisation techniques have also been discussed with an inner perspective on future of visual display of multidimensional complex information. The application of these techniques in some fields is also indicated.
Finite element analysis of tibial fractures
Wong, Christian Nai En; Mikkelsen, Mikkel Peter W; Hansen, Leif Berner
2010-01-01
INTRODUCTION: Fractures of the tibial shaft are relatively common injuries. There are indications that tibial shaft fractures share characteristics in terms of site, type and local fracture mechanisms. In this study, we aimed to set up a mathematical, computer-based model using finite element...... analysis of the bones of the lower leg to examine if such a model is adequate for prediction of fracture locations and patterns. In future studies, we aim to use these biomechanical results to examine fracture prevention, among others, and to simulate different types of osteosynthesis and the process...... Project. The data consisted of 21,219 3D elements with a cortical shell and a trabecular core. Three types of load of torsion, a direct lateral load and axial compression were applied. RESULTS: The finite element linear static analysis resulted in relevant fracture localizations and indicated relevant...
Finite element analysis of structures through unified formulation
Carrera, Erasmo; Petrolo, Marco; Zappino, Enrico
2014-01-01
The finite element method (FEM) is a computational tool widely used to design and analyse complex structures. Currently, there are a number of different approaches to analysis using the FEM that vary according to the type of structure being analysed: beams and plates may use 1D or 2D approaches, shells and solids 2D or 3D approaches, and methods that work for one structure are typically not optimized to work for another. Finite Element Analysis of Structures Through Unified Formulation deals with the FEM used for the analysis of the mechanics of structures in the case of linear elasticity. The novelty of this book is that the finite elements (FEs) are formulated on the basis of a class of theories of structures known as the Carrera Unified Formulation (CUF). It formulates 1D, 2D and 3D FEs on the basis of the same ''fundamental nucleus'' that comes from geometrical relations and Hooke''s law, and presents both 1D and 2D refined FEs that only have displacement variables as in 3D elements. It also covers 1D...
Finite Element Analysis of the LOLA Receiver Telescope Lens
Matzinger, Elizabeth
2007-01-01
This paper presents the finite element stress and distortion analysis completed on the Receiver Telescope lens of the Lunar Orbiter Laser Altimeter (LOLA). LOLA is one of six instruments on the Lunar Reconnaissance Orbiter (LRO), scheduled to launch in 2008. LOLA's main objective is to produce a high-resolution global lunar topographic model to aid in safe landings and enhance surface mobility in future exploration missions. The Receiver Telescope captures the laser pulses transmitted through a diffractive optical element (DOE) and reflected off the lunar surface. The largest lens of the Receiver Telescope, Lens 1, is a 150 mm diameter aspheric lens originally designed to be made of BK7 glass. The finite element model of the Receiver Telescope Lens 1 is comprised of solid elements and constrained in a manner consistent with the behavior of the mounting configuration of the Receiver Telescope tube. Twenty-one temperature load cases were mapped to the nodes based on thermal analysis completed by LOLA's lead thermal analyst, and loads were applied to simulate the preload applied from the ring flexure. The thermal environment of the baseline design (uncoated BK7 lens with no baffle) produces large radial and axial gradients in the lens. These large gradients create internal stresses that may lead to part failure, as well as significant bending that degrades optical performance. The high stresses and large distortions shown in the analysis precipitated a design change from BK7 glass to sapphire.
Orthodontic treatment: Introducing finite element analysis
Driel, W.D. van; Leeuwen, E.J. van
1998-01-01
The aim of orthodontic treatment is the displacement of teeth by means ofspecial appliances, like braces and brackets. Through these appliances the orthodontist can apply a set of forces to the teeth which wilt result in its displacement through the jawbone. Finite Element analysis of this process e
Advanced Materials and Solids Analysis Research Core (AMSARC)
The Advanced Materials and Solids Analysis Research Core (AMSARC), centered at the U.S. Environmental Protection Agency's (EPA) Andrew W. Breidenbach Environmental Research Center in Cincinnati, Ohio, is the foundation for the Agency's solids and surfaces analysis capabilities. ...
Advanced Materials and Solids Analysis Research Core (AMSARC)
The Advanced Materials and Solids Analysis Research Core (AMSARC), centered at the U.S. Environmental Protection Agency's (EPA) Andrew W. Breidenbach Environmental Research Center in Cincinnati, Ohio, is the foundation for the Agency's solids and surfaces analysis capabilities. ...
A cohesive finite element formulation for modelling fracture and delamination in solids
S Roy Chowdhury; R Narasimhan
2000-12-01
In recent years, cohesive zone models have been employed to simulate fracture and delamination in solids. This paper presents in detail the formulation for incorporating cohesive zone models within the framework of a large deformation finite element procedure. A special Ritz-finite element technique is employed to control nodal instabilities that may arise when the cohesive elements experience material softening and lose their stress carrying capacity. A few simple problems are presented to validate the implementation of the cohesive element formulation and to demonstrate the robustness of the Ritz solution method. Finally, quasi-static crack growth along the interface in an adhesively bonded system is simulated employing the cohesive zone model. The crack growth resistance curves obtained from the simulations show trends similar to those observed in experimental studies.
Finite element analysis of tibial fractures
Wong, Christian Nai En; Mikkelsen, Mikkel Peter W; Hansen, Leif Berner
2010-01-01
INTRODUCTION: Fractures of the tibial shaft are relatively common injuries. There are indications that tibial shaft fractures share characteristics in terms of site, type and local fracture mechanisms. In this study, we aimed to set up a mathematical, computer-based model using finite element...... analysis of the bones of the lower leg to examine if such a model is adequate for prediction of fracture locations and patterns. In future studies, we aim to use these biomechanical results to examine fracture prevention, among others, and to simulate different types of osteosynthesis and the process...... of bony healing. The biomechanical results are the basis for fracture healing, biomechanical fall analysis and stability analysis of osteosynthesis. MATERIAL AND METHODS: A finite element model of the bony part of the lower leg was generated on the basis of computed tomography data from the Visible Human...
Funari, Valerio, E-mail: valerio.funari@unibo.it [Dipartimento di Scienze Biologiche, Geologiche e Ambientali (BiGeA)—University of Bologna, Piazza di Porta San Donato 1, Bologna (Italy); Bokhari, Syed Nadeem Hussain [General and Analytical Chemistry—Montanuniversität Leoben, Franz-Josef-Str. 18, Leoben (Austria); Vigliotti, Luigi [Istituto di Scienze Marine (ISMAR-CNR)—National Research Council, Via Piero Gobetti 101, Bologna (Italy); Meisel, Thomas [General and Analytical Chemistry—Montanuniversität Leoben, Franz-Josef-Str. 18, Leoben (Austria); Braga, Roberto [Dipartimento di Scienze Biologiche, Geologiche e Ambientali (BiGeA)—University of Bologna, Piazza di Porta San Donato 1, Bologna (Italy)
2016-01-15
Highlights: • The REE concentrations of bottom and fly ashes from municipal incinerators are investigated. • First attempt toward discriminating the magnetic signature (susceptibility) of ashes from incinerators. • New methods and parameters for REE prospecting, which can be determined quickly and with limited costs, are provided. - Abstract: Bottom and fly ashes from Municipal Solid Waste Incinerators (MSWI) are hazardous products that present concern for their safe management. An attractive option to reduce their impact both on the environment and the financial commitment is turning MSWI ashes into secondary raw materials. In this study we present the REE content and distribution of bottom and fly ashes from MSWI after a highly effective digestion method and samples analysis by ICP–MS. The chondrite-normalised REE patterns of MSWI bottom and fly ash are comparable with that of crustal averages, suggesting a main geogenic source. Deviations from typical crustal pattern (e.g., Eu, Tb) disclose a contribution of likely anthropogenic provenance. The correlation with major elements indicates possible sources for REE and facilitates a preliminary resource assessment. Moreover, magnetic susceptibility measurements can be a useful prospecting method in urban ores made of MSWI ashes. The relationship between REE and some influencing parameters (e.g., Pricing Influence Factor) emphasises the importance of MSWI ash as alternative source of REE and the need of further efforts for REE recovery and purification from low concentrations but high flows waste.
Finite element analysis of bolted flange connections
Hwang, D. Y.; Stallings, J. M.
1994-06-01
A 2-D axisymmetric finite element model and a 3-D solid finite element model of a high pressure bolted flange joint were generated to investigate the stress behaviors. This investigation includes comparisons for axisymmetric loading of both the 2-D and 3-D models, the effects of non-axisymmetric bolt pretensions in the 3-D models, and the differences between 2-D and 3-D models subjected to non-axisymmetric loading. Comparisons indicated differences in von Mises stress up to 12% at various points due to the non-axisymmetric bolt pretensions. Applied bending moments were converted to equivalent axial forces for use in the 2-D model. It was found that the largest von Mises stresses in 3-D model did not occur on the side of the connection where the bending stresses and applied axial stresses were additive. Hence, in the 2-D model where the equivalent axial force (for bending moment) and applied axial forces were added, the 2-D model under estimated the maximum von Mises stress obtained from the 3-D model by 30%.
Jin Wencheng; Zhou Xiaoyong; Li Na
2008-01-01
A numerical model is developed in this paper to calculate the bending moments of flexural members through integration in 3D solid finite element analyses according to the nonlinear constitutive model of concrete and the elastoplastic constitutive model of steel, utilizing the stress condition of the cross-section, considering the destruction characteristic of reinforced concrete members, and based on the plane cross-section assumption. The results of this model give good agreement with those of the classical method. Consequently, we can also deduce the corresponding numerical expression for eccentrically loaded members according to the analysis method.
Chen, Li-Chieh; Huang, Mei-Jiau
2017-02-01
A 2D simulation method for a rigid body moving in an incompressible viscous fluid is proposed. It combines one of the immersed-boundary methods, the DFFD (direct forcing fictitious domain) method with the spectral element method; the former is employed for efficiently capturing the two-way FSI (fluid-structure interaction) and the geometric flexibility of the latter is utilized for any possibly co-existing stationary and complicated solid or flow boundary. A pseudo body force is imposed within the solid domain to enforce the rigid body motion and a Lagrangian mesh composed of triangular elements is employed for tracing the rigid body. In particular, a so called sub-cell scheme is proposed to smooth the discontinuity at the fluid-solid interface and to execute integrations involving Eulerian variables over the moving-solid domain. The accuracy of the proposed method is verified through an observed agreement of the simulation results of some typical flows with analytical solutions or existing literatures.
Bahattin Kanber; O.Yavuz Bozkurt
2006-01-01
In this work,the finite element analysis of the elasto-plastic plate bending problems is carried out using transition rectangular plate elements.The shape functions of the transition plate elements are derived based on a practical rule.The transition plate elements are all quadrilateral and can be used to obtain efficient finite element models using minimum number of elements.The mesh convergence rates of the models including the transition elements are compared with the regular element models.To verify the developed elements,simple tests are demonstrated and various elasto-plastic problems are solved.Their results are compared with ANSYS results.
Solid-gaseous phase transformation of elemental contaminants during the gasification of biomass.
Jiang, Ying; Ameh, Abiba; Lei, Mei; Duan, Lunbo; Longhurst, Philip
2016-09-01
Disposal of plant biomass removed from heavy metal contaminated land via gasification achieves significant volume reduction and can recover energy. However, these biomass often contain high concentrations of heavy metals leading to hot-corrosion of gasification facilities and toxic gaseous emissions. Therefore, it is of significant interest to gain a further understanding of the solid-gas phase transition of metal(loid)s during gasification. Detailed elemental analyses (C, H, O, N and key metal/metalloid elements) were performed on five plant species collected from a contaminated site. Using multi-phase equilibria modelling software (MTDATA), the analytical data allows modelling of the solid/gas transformation of metal(loid)s during gasification. Thermodynamic modelling based on chemical equilibrium calculations was carried out in this study to predict the fate of metal(loid) elements during typical gasification conditions and to show how these are influenced by metal(loid) composition in the biomass and operational conditions. As, Cd, Zn and Pb tend to transform to their gaseous forms at relatively low temperatures (1200°C). Simulation of pressurised gasification conditions shows that higher pressures increase the temperature at which solid-to-gaseous phase transformations takes place.
Structural analysis of reactor fuel elements
Weeks, R.W.
1977-01-01
An overview of fuel-element modeling is presented that traces the development of codes for the prediction of light-water-reactor and fast-breeder-reactor fuel-element performance. It is concluded that although the mathematical analysis is now far advanced, the development and incorporation of mechanistic constitutive equations has not kept pace. The resultant reliance on empirical correlations severely limits the physical insight that can be gained from code extrapolations. Current efforts include modeling of alternate fuel systems, analysis of local fuel-cladding interactions, and development of a predictive capability for off-normal behavior. Future work should help remedy the current constitutive deficiencies and should include the development of deterministic failure criteria for use in design.
Introduction to nonlinear finite element analysis
Kim, Nam-Ho
2015-01-01
This book introduces the key concepts of nonlinear finite element analysis procedures. The book explains the fundamental theories of the field and provides instructions on how to apply the concepts to solving practical engineering problems. Instead of covering many nonlinear problems, the book focuses on three representative problems: nonlinear elasticity, elastoplasticity, and contact problems. The book is written independent of any particular software, but tutorials and examples using four commercial programs are included as appendices: ANSYS, NASTRAN, ABAQUS, and MATLAB. In particular, the MATLAB program includes all source codes so that students can develop their own material models, or different algorithms. This book also: · Presents clear explanations of nonlinear finite element analysis for elasticity, elastoplasticity, and contact problems · Includes many informative examples of nonlinear analyses so that students can clearly understand the nonlinear theory · ...
Finite element contact analysis of fractal surfaces
Sahoo, Prasanta; Ghosh, Niloy [Department of Mechanical Engineering, Jadavpur University, Kolkata 700032 (India)
2007-07-21
The present study considers finite element analysis of non-adhesive, frictionless elastic/elastic-plastic contact between a rigid flat plane and a self-affine fractal rough surface using the commercial finite element package ANSYS. Three-dimensional rough surfaces are generated using a modified two-variable Weierstrass-Mandelbrot function with given fractal parameters. Parametric studies are done to consider the general relations between contact properties and key material and surface parameters. The present analysis is validated with available experimental results in the literature. Non-dimensional contact area and displacement are obtained as functions of non-dimensional load for varying fractal surface parameters in the case of elastic contact and for varying rates of strain hardening in the case of elastic-plastic contact of fractal surfaces.
Finite element analysis of (SA) mechanoreceptors in tactile sensing application
N, Syamimi; Yahud, S.
2015-05-01
This paper addresses the structural design of a fingertip model in order to analyse the sensory function of slow adapting (SA) mechanoreceptors by using the finite element analysis (FEA) method. A biologically inspired tactile sensor was designed to mimic a similar response of the human mechanoreceptors in the human glabrous skin. The simulation work was done by using COMSOL Multiphysics. The artificial skin was modelled as a solid square block of silicone elastomer with a semi cylinder protrusion on top. It was modelled as a nearly incompressible and linear hyperelastic material defined by Neo Hookean constitutive law. The sensing element on the other hand was modelled by using constantan alloy mimicking the SA1 receptor. Boundary loads of 1 N/m² to 4 N/m² with the increment of 1 N/m² were applied to the top surface of the protrusion in z and x-direction for normal and shear stress, respectively. The epidermal model base was constrained to maintain the same boundary conditions throughout all simulations. The changes of length experienced by the sensing element were calculated. The simulations result in terms of strain was identified. The simulated result was plotted in terms of sensing element strain against the boundary load and the graph should produce a linear response.
SUPERCONVERGENCE ANALYSIS FOR CUBIC TRIANGULAR ELEMENT OF THE FINITE ELEMENT
Qi-ding Zhu
2000-01-01
In this paper, we construct a projection interpolation for cubic triangular ele- ment by using othogonal expansion triangular method. We show two fundamental formulas of estimation on a special partion and obtain a superconvergence result of 1 -e order higher for the placement function and its tangential derivative on the third order Lobatto points and Gauss points on each edge of triangular element.
Geometrically Nonlinear Finite Element Analysis of a Composite Space Reflector
Lee, Kee-Joo; Leet, Sung W.; Clark, Greg; Broduer, Steve (Technical Monitor)
2001-01-01
Lightweight aerospace structures, such as low areal density composite space reflectors, are highly flexible and may undergo large deflection under applied loading, especially during the launch phase. Accordingly, geometrically nonlinear analysis that takes into account the effect of finite rotation may be needed to determine the deformed shape for a clearance check and the stress and strain state to ensure structural integrity. In this study, deformation of the space reflector is determined under static conditions using a geometrically nonlinear solid shell finite element model. For the solid shell element formulation, the kinematics of deformation is described by six variables that are purely vector components. Because rotational angles are not used, this approach is free of the limitations of small angle increments. This also allows easy connections between substructures and large load increments with respect to the conventional shell formulation using rotational parameters. Geometrically nonlinear analyses were carried out for three cases of static point loads applied at selected points. A chart shows results for a case when the load is applied at the center point of the reflector dish. The computed results capture the nonlinear behavior of the composite reflector as the applied load increases. Also, they are in good agreement with the data obtained by experiments.
Finite Element Analysis of Reverberation Chambers
Bunting, Charles F.; Nguyen, Duc T.
2000-01-01
The primary motivating factor behind the initiation of this work was to provide a deterministic means of establishing the validity of the statistical methods that are recommended for the determination of fields that interact in -an avionics system. The application of finite element analysis to reverberation chambers is the initial step required to establish a reasonable course of inquiry in this particularly data-intensive study. The use of computational electromagnetics provides a high degree of control of the "experimental" parameters that can be utilized in a simulation of reverberating structures. As the work evolved there were four primary focus areas they are: 1. The eigenvalue problem for the source free problem. 2. The development of a complex efficient eigensolver. 3. The application of a source for the TE and TM fields for statistical characterization. 4. The examination of shielding effectiveness in a reverberating environment. One early purpose of this work was to establish the utility of finite element techniques in the development of an extended low frequency statistical model for reverberation phenomena. By employing finite element techniques, structures of arbitrary complexity can be analyzed due to the use of triangular shape functions in the spatial discretization. The effects of both frequency stirring and mechanical stirring are presented. It is suggested that for the low frequency operation the typical tuner size is inadequate to provide a sufficiently random field and that frequency stirring should be used. The results of the finite element analysis of the reverberation chamber illustrate io-W the potential utility of a 2D representation for enhancing the basic statistical characteristics of the chamber when operating in a low frequency regime. The basic field statistics are verified for frequency stirring over a wide range of frequencies. Mechanical stirring is shown to provide an effective frequency deviation.
Viscoelastic finite-element analysis of human skull - dura mater ...
SERVER
2008-03-18
Mar 18, 2008 ... In the work, the dynamic characteristics of the human skull-dura mater ... Ansys' finite element processor, a simplified three-dimensional finite element ... brain, cerebrospinal fluid (CSF), and the brain's blood ... ICP is often not preventable. .... The creep of linear viscoelastic solid can be simulated by the.
Morf, Leo S., E-mail: leo.morf@bd.zh.ch [Baudirektion Kanton Zürich, Amt für Abfall, Wasser, Energie und Luft, Zurich (Switzerland); Gloor, Rolf; Haag, Olaf [Bachema AG, Schlieren (Switzerland); Haupt, Melanie [Zentrum für nachhaltige Abfall-und Ressourcennutzung ZAR, Hinwil (Switzerland); Skutan, Stefan [Bachema AG, Schlieren (Switzerland); Lorenzo, Fabian Di; Böni, Daniel [Zentrum für nachhaltige Abfall-und Ressourcennutzung ZAR, Hinwil (Switzerland)
2013-03-15
Highlights: ► We carefully addressed all the very valuable comments and suggestions of the reviewers. ► We also have shortened the size of the paper and tried simplify it substantially, as requested by the reviewers (introduction 25% reduced!). ► We have decided to take the chance and have replaced the data for the “additional” elements (Cu, Cd, Zn, Pb, Sn, Cr, Ni, Fe, Al) of the earlier MFA (Morf, 2011) with data that belong to the samples of this study. ► We are convinced that with the revision the paper has significantly improved in quality and attractiveness. - Abstract: In Switzerland many kinds of waste, e.g. paper, metals, electrical and electronic equipment are separately collected and recycled to a large extent. The residual amount of municipal solid waste (MSW) has to be thermally treated before final disposal. Efforts to recover valuable metals from incineration residues have recently increased. However, the resource potential of critical elements in the waste input (sources) and their partitioning into recyclable fractions and residues (fate) is unknown. Therefore, a substance flow analysis (SFA) for 31 elements including precious metals (Au, Ag), platinum metal group elements (Pt, Rh) and rare earth elements (La, Ce, etc.) has been conducted in a solid waste incinerator (SWI) with a state-of-the-art bottom ash treatment according to the Thermo-Re® concept. The SFA allowed the determination of the element partitioning in the SWI, as well as the elemental composition of the MSW by indirect analysis. The results show that the waste-input contains substantial quantities of precious metals, such as 0.4 ± 0.2 mg/kg Au and 5.3 ± 0.7 mg/kg Ag. Many of the valuable substances, such as Au and Ag are enriched in specific outputs (e.g. non-ferrous metal fractions) and are therefore recoverable. As the precious metal content in MSW is expected to rise due to its increasing application in complex consumer products, the results of this study are
Discrete Element Analysis of Huangtupo Landslide
无
2002-01-01
On the basis of the deep geology and the geological structure of Huangtupo landslide, an ancient landslide in the reservoir of the Three Gorges, the geo-environmental model of the landslide is established to analyze quantitatively the sliding mechanism by using the discrete element method. It is concluded that interbedding structure of soft and hard formation consists of the main geological background,which induced the arching of the formation under gravity. Stability analysis of different loadings shows that the ground building weight on the middle slope may restrain the extension of shear sliding zone below, but may activate the foot area which will reduce the safety factor of the front.
Bao, Weizhu; Jiang, Wei; Wang, Yan; Zhao, Quan
2017-02-01
We propose an efficient and accurate parametric finite element method (PFEM) for solving sharp-interface continuum models for solid-state dewetting of thin films with anisotropic surface energies. The governing equations of the sharp-interface models belong to a new type of high-order (4th- or 6th-order) geometric evolution partial differential equations about open curve/surface interface tracking problems which include anisotropic surface diffusion flow and contact line migration. Compared to the traditional methods (e.g., marker-particle methods), the proposed PFEM not only has very good accuracy, but also poses very mild restrictions on the numerical stability, and thus it has significant advantages for solving this type of open curve evolution problems with applications in the simulation of solid-state dewetting. Extensive numerical results are reported to demonstrate the accuracy and high efficiency of the proposed PFEM.
Miyamura, Tomoshi; Yamashita, Takuzo; AKIBA,HIROSHI; Ohsaki, Makoto
2015-01-01
Dynamic finite element analyses of a four-story steel building frame modeled as a fine mesh of solid elements are performed using E-Simulator, which is a parallel finite element analysis software package for precisely simulating collapse behaviors of civil and building structures. E-Simulator is under development at the National Research Institute for Earth Science and Disaster Prevention (NIED), Japan. A full-scale shake-table test for a four-story frame was conducted using E-Defense at NIED...
Rolland, A.; Aufray, B.
1985-10-01
This paper deals with a comparative study of surface segragation of Pb and Ni respectively from Ag(Pb)(111) and Ag(Ni)(111) solid solutions. A high level of segregation of the solute is observed for both systems characterized by very low solute solubility. However, the superficial composition strongly depends on the relative surface tensions of the pure elements: the solute atoms are strictly on superficial sites when γ solute is smaller than γ solvent; in contrast uppermost layer consists purely of solvent when γ solute is greater than γ solvent. Two schematic distributions in close proximity to the surface are proposed in the last case.
Impeller deflection and modal finite element analysis.
Spencer, Nathan A.
2013-10-01
Deflections of an impeller due to centripetal forces are calculated using finite element analysis. The lateral, or out of plane, deflections are an important design consideration for this particular impeller because it incorporates an air bearing with critical gap tolerances. The target gap distance is approximately 10 microns at a rotational velocity of 2500 rpm. The centripetal forces acting on the impeller cause it deflect in a concave fashion, decreasing the initial gap distance as a function of radial position. This deflection is characterized for a previous and updated impeller design for comparative purposes. The impact of design options such as material selection, geometry dimensions, and operating rotational velocity are also explored, followed by a sensitivity study with these parameters bounded by specific design values. A modal analysis is also performed to calculate the impeller's natural frequencies which are desired to be avoided during operation. The finite element modeling techniques continue to be exercised by the impeller design team to address specific questions and evaluate conceptual designs, some of which are included in the Appendix.
Inelastic analysis of solids and structures
Kojic, M; Bathe, K J; Koji?, Milo
2005-01-01
Inelastic Analysis of Solids and Structures presents in a unified manner the physical and theoretical background of inelastic material models and computational methods, and illustrates the behavior of the models in typical engineering conditions.It is based on experimental observations and principles of mechanics, thus describing computational algorithms for stress calculation and presenting solved examples.The theoretical background is given to an extent necessary to describe the commonly employed material models in metal isotropic and orthotropic plasticity, thermoplasticity and viscoplasticity, and the plasticity of geological materials.The computational algorithms are developed in a unified manner with some detailed derivations of the algorithmic relations.The solved examples are designed to give insight into the material behavior in various engineering conditions, and to demonstrate the application of the computational algorithms.
Elemental analysis of silver coins by PIXE technique
Tripathy, B.B. [Department of Physics, Silicon Institute of Technology, Patia, Bhubaneswar 751 024 (India); Rautray, Tapash R. [Department of Dental Biomaterials, School of Dentistry, Kyungpook National University, 2-188-1 Samduk -dong, Jung-gu, Daegu 700 412 (Korea, Republic of); ARASMIN, G. Udayagiri, Kandhamal, Orissa 762 100 (India)], E-mail: tapash.rautray@gmail.com; Rautray, A.C. [ARASMIN, G. Udayagiri, Kandhamal, Orissa 762 100 (India); Vijayan, V. [Praveen Institute of Radiation Technology, Flat No. 9A, Avvai Street, New Perungalathur, Chennai 600 063 (India)
2010-03-15
Elemental analysis of nine Indian silver coins during British rule was carried out by proton induced X-ray emission spectroscopy. Eight elements, namely Cr, Fe, Ni, Cu, Zn, As, Ag, and Pb were determined in the present study. Ag and Cu were found to be the major elements, Zn was the only minor element and all other elements are present at the trace level. The variation of the elemental concentration may be due to the use of different ores for making coins.
Solid Phase Biosensors for Arsenic or Cadmium Composed of A trans Factor and cis Element Complex
Mohammad Shohel Rana Siddiki
2011-10-01
Full Text Available The presence of toxic metals in drinking water has hazardous effects on human health. This study was conducted to develop GFP-based-metal-binding biosensors for on-site assay of toxic metal ions. GFP-tagged ArsR and CadC proteins bound to a cis element, and lost the capability of binding to it in their As- and Cd-binding conformational states, respectively. Water samples containing toxic metals were incubated on a complex of GFP-tagged ArsR or CadC and cis element which was immobilized on a solid surface. Metal concentrations were quantified with fluorescence intensity of the metal-binding states released from the cis element. Fluorescence intensity obtained with the assay significantly increased with increasing concentrations of toxic metals. Detection limits of 1 μg/L for Cd(II and 5 μg/L for As(III in purified water and 10 µg/L for Cd(II and As(III in tap water and bottled mineral water were achieved by measurement with a battery-powered portable fluorometer after 15-min and 30-min incubation, respectively. A complex of freeze dried GFP-tagged ArsR or CadC binding to cis element was stable at 4 °C and responded to 5 μg/L As(III or Cd(II. The solid phase biosensors are sensitive, less time-consuming, portable, and could offer a protocol for on-site evaluation of the toxic metals in drinking water.
Nami, B. [School of Metallurgy and Materials Engineering, Iran University of Science and Technology (IUST), Narmak, Tehran (Iran, Islamic Republic of); Shabestari, S.G., E-mail: shabestari@iust.ac.ir [Center of Excellence for Advanced Materials and Processing (CEAMP), School of Metallurgy and Materials Engineering, Iran University of Science and Technology (IUST), Narmak, Tehran (Iran, Islamic Republic of); Razavi, H. [School of Metallurgy and Materials Engineering, Iran University of Science and Technology (IUST), Narmak, Tehran (Iran, Islamic Republic of); Mirdamadi, Sh. [Center of Excellence for Advanced Materials and Processing (CEAMP), School of Metallurgy and Materials Engineering, Iran University of Science and Technology (IUST), Narmak, Tehran (Iran, Islamic Republic of); Miresmaeili, S.M. [Department of Mechanical Engineering, Shahid Rajaee Teacher Training University (SRTTU), Lavizan, Tehran (Iran, Islamic Republic of)
2011-01-25
Research highlights: {yields} The size of solid globular {alpha}(Mg) particles decreases in semi-solid slurries of AZ91 alloy by adding Ca and RE elements, whereas it has no considerable effect on the shape factor of the solid particles. {yields} Particle growth in semi-solid slurries of AZ91 and AZRC91 alloys takes place by Ostwald ripening mechanism. {yields} The coarsening rate of solid particles in semi-solid slurries of AZRC91 alloy is lower than that of AZ91 alloy. {yields} Creep properties of AZ91 alloy was improved by adding Ca and RE elements. The thixoformed specimens exhibit the better creep resistance than the as-cast specimens. - Abstract: The effects of calcium and rare earth elements (RE) on the microstructure and creep properties of as-cast and thixoformed AZ91 magnesium alloy have been investigated. It has been shown that the amount of {beta}(Mg{sub 17}Al{sub 12}) intermetallic compound decreases by adding Ca and RE elements into AZ91 alloy and new Al{sub 11}RE{sub 3} and Al{sub 2}Ca intermetallic compounds form in the microstructure. The coarsening of primary {alpha}(Mg) particles in AZ91 alloy and in the Ca and RE containing (AZRC91) alloy takes place by Ostwald ripening mechanism. Adding Ca and RE elements into AZ91 alloy results in a decrease in the coarsening rate of solid particles in semi-solid slurry, whereas it has no visible effect on the shape factor of the solid-particles. The creep properties of AZ91 alloy are improved by adding Ca and RE elements particularly, in the thixoformed condition.
Nonlinear finite-element analysis and biomechanical evaluation of the lumbar spine
Wong, Christian; Gehrchen, P Martin; Darvann, Tron;
2003-01-01
A finite-element analysis (FEA) model of an intact lumbar disc-body unit was generated. The vertebral body of the FEA model consisted of a solid tetrahedral core of trabecular bone surrounded by a cortical shell. The disc consisted of an incompressible nucleus surrounded by nonlinear annulus fibers...
An inverse finite element method for determining residual and current stress fields in solids
Tartibi, M.; Steigmann, D. J.; Komvopoulos, K.
2016-11-01
The life expectancy of a solid component is traditionally predicted by assessing its expected stress cycle and comparing it to experimentally determined stress states at failure. The accuracy of this procedure is often compromised by unforeseen extremes in the loading cycle or material degradation. Residually stressed parts may either have longer or shorter lifespans than predicted. Thus, determination of the current state of stress (i.e., the residual stress in the absence of external loading) and material properties is particularly important. Typically, the material properties of a solid are determined by fitting experimental data obtained from the measured deformation response in the stress-free configuration. However, the characterization of the mechanical behavior of a residually stressed body requires, in principle, a method that is not restricted to specific constitutive models. Complementing a recently developed technique, known as the reversed updated Lagrangian finite element method (RULFEM), a new method called estimating the current state of stress (ECSS) is presented herein. ECSS is based on three-dimensional full-field displacement and force data of a body perturbed by small displacements and complements the first step of the incremental RULFEM method. The present method generates the current state of stress (or residual stress in the absence of external tractions) and the incremental elasticity tensor of each finite element used to discretize the deformable body. The validity of the ECSS method is demonstrated by two noise-free simulation cases.
An inverse finite element method for determining residual and current stress fields in solids
Tartibi, M.; Steigmann, D. J.; Komvopoulos, K.
2016-08-01
The life expectancy of a solid component is traditionally predicted by assessing its expected stress cycle and comparing it to experimentally determined stress states at failure. The accuracy of this procedure is often compromised by unforeseen extremes in the loading cycle or material degradation. Residually stressed parts may either have longer or shorter lifespans than predicted. Thus, determination of the current state of stress (i.e., the residual stress in the absence of external loading) and material properties is particularly important. Typically, the material properties of a solid are determined by fitting experimental data obtained from the measured deformation response in the stress-free configuration. However, the characterization of the mechanical behavior of a residually stressed body requires, in principle, a method that is not restricted to specific constitutive models. Complementing a recently developed technique, known as the reversed updated Lagrangian finite element method (RULFEM), a new method called estimating the current state of stress (ECSS) is presented herein. ECSS is based on three-dimensional full-field displacement and force data of a body perturbed by small displacements and complements the first step of the incremental RULFEM method. The present method generates the current state of stress (or residual stress in the absence of external tractions) and the incremental elasticity tensor of each finite element used to discretize the deformable body. The validity of the ECSS method is demonstrated by two noise-free simulation cases.
Finite element analysis of multilayer coextrusion.
Hopkins, Matthew Morgan; Schunk, Peter Randall; Baer, Thomas A. (Proctor & Gamble Company, West Chester, OH); Mrozek, Randy A. (Army Research Laboratory, Adelphi, MD); Lenhart, Joseph Ludlow (Army Research Laboratory, Adelphi, MD); Rao, Rekha Ranjana; Collins, Robert (Oak Ridge National Laboratory); Mondy, Lisa Ann
2011-09-01
Multilayer coextrusion has become a popular commercial process for producing complex polymeric products from soda bottles to reflective coatings. A numerical model of a multilayer coextrusion process is developed based on a finite element discretization and two different free-surface methods, an arbitrary-Lagrangian-Eulerian (ALE) moving mesh implementation and an Eulerian level set method, to understand the moving boundary problem associated with the polymer-polymer interface. The goal of this work is to have a numerical capability suitable for optimizing and troubleshooting the coextrusion process, circumventing flow instabilities such as ribbing and barring, and reducing variability in layer thickness. Though these instabilities can be both viscous and elastic in nature, for this work a generalized Newtonian description of the fluid is used. Models of varying degrees of complexity are investigated including stability analysis and direct three-dimensional finite element free surface approaches. The results of this work show how critical modeling can be to reduce build test cycles, improve material choices, and guide mold design.
1975-12-31
The development program for HTGR fuel reprocessing continues to emphasize the design and construction of a prototype head-end line. Design work on the multistage crushing system, the primary and secondary fluidized bed burners, the pneumatic transfer systems, and the ancillary fixtures for semiremote assembly and disassembly is essentially complete. Fabrication and receipt of all major components is under way, and auxiliary instrumentation and support systems are being installed. Studies of flow characteristics of granular solids in pneumatic transfer systems are continuing and data are being collected for use in design of systems for solids handling. Experimental work on the 20-cm primary fluidized bed burner verified the fines recycle operating mode in runs of greater than 24 hr. Twelve leaching runs were performed during the quarter using crushed, burned-back TRISO coated ThC/sub 2/ particles and burned-back BISO coated sol gel ThO/sub 2/ particles to examine the effect of varying the Thorex-to-thoria ratio to give product solutions ranging from 0.25M to 1M in thorium. Only minor effects were observed and reference values for facility operations were specified. Two-stage leaching runs with burned-back ThC/sub 2/ indicate there are no measurable differences in total dissolution time as compared to single-stage leaching. Bench-scale tests on oxidation of HTGR fuel boron carbide at 900/sup 0/C indicates that most if not all of the carbide will be converted to boron oxide in the fluidized bed burner. Eight solvent extraction runs were completed during the quarter. These runs represented the first cycle and second uranium cycle of the acid-Thorex flowsheet. A detailed calculation of spent fuel compositions by fuel block and particle type is being performed for better definition of process streams in a fuel reprocessing facility.
ACCURACY ANALYSIS FOR QUASI-CAREY ELEMENT
Dongyang SHI; Xiaobin HAO
2008-01-01
In this paper, a new triangular element (Quasi-Carey element) is constructed by the idea of Specht element. It is shown that this Quasi-Carey element possesses a very special property, i.e.,the consistency error is of order O(h2), one order higher than its interpolation error when the exact solution belongs to Ha(Ω). However, the interpolation error and consistency error of Carey element are of order O(h). It seems that the above special property has never been seen for other triangular elements for the second order problems.
Investigation of Shear Stud Performance in Flat Plate Using Finite Element Analysis
T.S. Viswanathan
2014-09-01
Full Text Available Three types of shear stud arrangement, respectively featuring an orthogonal, a radial and a critical perimeter pattern, were evaluated numerically. A numerical investigation was conducted using the finite element software ABAQUS to evaluate their ability to resist punching shear in a flat plate. The finite element analysis here is an application of the nonlinear analysis of reinforced concrete structures using three-dimensional solid finite elements. The nonlinear characteristics of concrete were achieved by employing the concrete damaged plasticity model in the finite element program. Transverse shear stress was evaluated using finite element analysis in terms of shear stress distribution for flat plate with and without shear stud reinforcement. The model predicted that shear studs placed along the critical perimeter are more effective compared to orthogonal and radial patterns.
Investigation of the Behavior of Steel Shear Walls Using Finite Elements Analysis
K. Abubakri
2016-10-01
Full Text Available Currently, steel shear walls are considered by engineers as an economic method against lateral loads imposed by wind and earthquake in tall structures. Accordingly, there is a growing need to develop accurate methods alongside approximation methods to estimate the behavior of these structural elements. The finite element technique is one of the strongest numerical methods in analysis of solid mechanics problems. Finite element analysis however requires high technical knowledge of the behavioral models of materials. Therefore, it is less used by designers for certain structural elements such as steel shear walls. This study examines the failure mechanism of steel shear walls using finite elements analysis and validates this modeling by comparing the results with experimental studies.
Solid Launcher Dynamical Analysis and Autopilot Design
Ping Sun
2011-02-01
Full Text Available The dynamics of a small solid launch vehicle has been investigated. This launcher consists of a liquid upper stage and three fundamental solid rocket boosters aligned in series. During the ascent flight phase, lateral jets and grid fins are adopted by the flight control system to stable the attitude of the launcher. The launcher is a slender and aerodynamically unstable vehicle with sloshing tanks. A complete set of six-degrees-of-freedom dynamic models of the launcher, incorporation its rigid body, aerodynamics, gravity, sloshing, mass change, actuator, and elastic body, is developed. Dynamic analysis results of the structural modes and the bifurcation locus are calculated on the basis of the presented models. This complete set of dynamic models is used in flight control system design. A methodology for employing numerical optimization to develop the attitude filters is presented. The design objectives include attitude tracking accuracy and robust stability with respect to rigid body dynamics, propellant slosh, and flex. Later a control approach is presented for flight control system of the launcher using both State Dependent Riccati Equation (SDRE method and Fast Output Sampling (FOS technique. The dynamics and kinematics for attitude stable problem are of typical nonlinear character. SDRE technique has been well applied to this kind of highly nonlinear control problems. But in practice the system states needed in the SDRE method are sometimes difficult to obtain. FOS method, which makes use of only the output samples, is combined with SDRE to accommodate the incomplete system state information. Thus, the control approach is more practical and easy to implement. The resulting autopilot can provide stable control systems for the vehicle.
Maker, B.N.
1995-04-14
This report provides a user`s manual for NIKE3D, a fully implicit three-dimensional finite element code for analyzing the finite strain static and dynamic response of inelastic solids, shells, and beams. Spatial discretization is achieved by the use of 8-node solid elements, 2-node truss and beam elements, and 4-node membrane and shell elements. Over twenty constitutive models are available for representing a wide range of elastic, plastic, viscous, and thermally dependent material behavior. Contact-impact algorithms permit gaps, frictional sliding, and mesh discontinuities along material interfaces. Several nonlinear solution strategies are available, including Full-, Modified-, and Quasi-Newton methods. The resulting system of simultaneous linear equations is either solved iteratively by an element-by-element method, or directly by a factorization method, for which case bandwidth minimization is optional. Data may be stored either in or out of core memory to allow for large analyses.
Sorption of redox-sensitive elements: critical analysis
Strickert, R.G.
1980-12-01
The redox-sensitive elements (Tc, U, Np, Pu) discussed in this report are of interest to nuclear waste management due to their long-lived isotopes which have a potential radiotoxic effect on man. In their lower oxidation states these elements have been shown to be highly adsorbed by geologic materials occurring under reducing conditions. Experimental research conducted in recent years, especially through the Waste Isolation Safety Assessment Program (WISAP) and Waste/Rock Interaction Technology (WRIT) program, has provided extensive information on the mechanisms of retardation. In general, ion-exchange probably plays a minor role in the sorption behavior of cations of the above three actinide elements. Formation of anionic complexes of the oxidized states with common ligands (OH/sup -/, CO/sup - -//sub 3/) is expected to reduce adsorption by ion exchange further. Pertechnetate also exhibits little ion-exchange sorption by geologic media. In the reduced (IV) state, all of the elements are highly charged and it appears that they form a very insoluble compound (oxide, hydroxide, etc.) or undergo coprecipitation or are incorporated into minerals. The exact nature of the insoluble compounds and the effect of temperature, pH, pe, other chemical species, and other parameters are currently being investigated. Oxidation states other than Tc (IV,VII), U(IV,VI), Np(IV,V), and Pu(IV,V) are probably not important for the geologic repository environment expected, but should be considered especially when extreme conditions exist (radiation, temperature, etc.). Various experimental techniques such as oxidation-state analysis of tracer-level isotopes, redox potential measurement and control, pH measurement, and solid phase identification have been used to categorize the behavior of the various valence states.
Finite element analysis of flexible, rotating blades
Mcgee, Oliver G.
1987-01-01
A reference guide that can be used when using the finite element method to approximate the static and dynamic behavior of flexible, rotating blades is given. Important parameters such as twist, sweep, camber, co-planar shell elements, centrifugal loads, and inertia properties are studied. Comparisons are made between NASTRAN elements through published benchmark tests. The main purpose is to summarize blade modeling strategies and to document capabilities and limitations (for flexible, rotating blades) of various NASTRAN elements.
Prediction and phylogenetic analysis of mammalian short interspersed elements (SINEs).
Rogozin, I B; Mayorov, V I; Lavrentieva, M V; Milanesi, L; Adkison, L R
2000-09-01
The presence of repetitive elements can create serious problems for sequence analysis, especially in the case of homology searches in nucleotide sequence databases. Repetitive elements should be treated carefully by using special programs and databases. In this paper, various aspects of SINE (short interspersed repetitive element) identification, analysis and evolution are discussed.
He, Man; Huang, Lijin; Zhao, Bingshan; Chen, Beibei; Hu, Bin
2017-06-22
For the determination of trace elements and their species in various real samples by inductively coupled plasma mass spectrometry (ICP-MS), solid phase extraction (SPE) is a commonly used sample pretreatment technique to remove complex matrix, pre-concentrate target analytes and make the samples suitable for subsequent sample introduction and measurements. The sensitivity, selectivity/anti-interference ability, sample throughput and application potential of the methodology of SPE-ICP-MS are greatly dependent on SPE adsorbents. This article presents a general overview of the use of advanced functional materials (AFMs) in SPE for ICP-MS determination of trace elements and their species in the past decade. Herein the AFMs refer to the materials featuring with high adsorption capacity, good selectivity, fast adsorption/desorption dynamics and satisfying special requirements in real sample analysis, including nanometer-sized materials, porous materials, ion imprinting polymers, restricted access materials and magnetic materials. Carbon/silica/metal/metal oxide nanometer-sized adsorbents with high surface area and plenty of adsorption sites exhibit high adsorption capacity, and porous adsorbents would provide more adsorption sites and faster adsorption dynamics. The selectivity of the materials for target elements/species can be improved by using physical/chemical modification, ion imprinting and restricted accessed technique. Magnetic adsorbents in conventional batch operation offer unique magnetic response and high surface area-volume ratio which provide a very easy phase separation, greater extraction capacity and efficiency over conventional adsorbents, and chip-based magnetic SPE provides a versatile platform for special requirement (e.g. cell analysis). The performance of these adsorbents for the determination of trace elements and their species in different matrices by ICP-MS is discussed in detail, along with perspectives and possible challenges in the future
Study of atmospheric pollution levels by trace elements analysis of ...
Study of atmospheric pollution levels by trace elements analysis of tree bark and leaves. ... Bulletin of the Chemical Society of Ethiopia ... The high-pollution automobile parking lots showed higher levels of these elements (p < 0.05).
Finite Element Analysis (FEA) in Design and Production.
Waggoner, Todd C.; And Others
1995-01-01
Finite element analysis (FEA) enables industrial designers to analyze complex components by dividing them into smaller elements, then assessing stress and strain characteristics. Traditionally mainframe based, FEA is being increasingly used in microcomputers. (SK)
Optimization Design and Finite Element Analysis of Core Cutter
CAO Pin-lu; YIN Kun; PENG Jian-ming; LIU Jian-lin
2007-01-01
The hydro-hammer sampler is a new type of sampler compared with traditional ones. An important part of this new offshore sampler is that the structure of the core cutter has a significant effect on penetration and core recovery. In our experiments, a commercial finite element code with a capability of simulating large-strain frictional contact between two or more solid bodies is used to simulate the core cutter-soil interaction. The effects of the cutting edge shape, the diameter and the edge angle on penetration are analyzed by non-liner transient dynamic analysis using a finite element method (FEM). Simulation results show that the cutter shape clearly has an effect on the penetration and core recovery. In addition, the penetration of the sampler increases with an increase in the inside diameter of the cutter, but decreases with an increase in the cutting angle. Based on these analyses, an optimum structure of the core cutter is designed and tested in the north margin of the Dalian gulf. Experiment results show that the penetration rate is about 16.5 m/h in silty clay and 15.4 m/h in cohesive clay, while the recovery is 68% and 83.3% respectively.
A mixed formulation finite element for linear thin shell analysis
Lee, S. W.; Wong, S. C.
1982-01-01
An eight node curved thin shell slement was tested. The element is based on the degenerate solid concept and the mixed formulation with the independent inplane and transverse shear strains. The number of unknown parameters in the assumed strains is chosen to alleviate the spurious constaining or locking effect. It is indicated that for a pinched cylindrical shell with diaphragmed ends and fixed ends the present element shows good performance.
CONVERGENCE ANALYSIS FOR A NONCONFORMING MEMBRANE ELEMENT ON ANISOTROPIC MESHES
Dong-yang Shi; Shao-chun Chen; Ichiro Hagiwara
2005-01-01
Regular assumption of finite element meshes is a basic condition of most analysis of finite element approximations both for conventional conforming elements and nonconforming elements. The aim of this paper is to present a novel approach of dealing with the approximation of a four-degree nonconforming finite element for the second order elliptic problems on the anisotropic meshes. The optimal error estimates of energy norm and L2-norm without the regular assumption or quasi-uniform assumption are obtained based on some new special features of this element discovered herein. Numerical results are given to demonstrate validity of our theoretical analysis.
Finite element methodology for transient conduction/forced-convection thermal analysis
Thornton, E. A.; Wieting, A. R.
1979-01-01
Finite element methodology for steady state thermal analysis of convectively cooled structures has been extended for transient analysis. The finite elements are based on representing the fluid passages by fluid bulk-temperature nodes and fluid-solid interface nodes. The formulation of the finite element equations for a typical flow passage is based on the weighted residual method with upwind weighting functions. Computer implementation of the convective finite element methodology using explicit and implicit time integration algorithms is described. Accuracy and efficiency of the methodology is evaluated by comparisons with analytical solutions and finite-difference lumped-parameter analyses. The comparative analyses demonstrate that finite element conduction/conduction methodology may be used to predict transient temperatures with an accuracy equal or superior to the lumped-parameter finite-difference method.
Schwerdtfeger, Peter
2016-12-01
In the last two decades cold and hot fusion experiments lead to the production of new elements for the Periodic Table up to nuclear charge 118. Recent developments in relativistic quantum theory have made it possible to obtain accurate electronic properties for the trans-actinide elements with the aim to predict their potential chemical and physical behaviour. Here we report on first results of solid-state calculations for Og (element 118) to support future atom-at-a-time gas-phase adsorption experiments on surfaces such as gold or quartz.
Three-Dimensional Effects in the Plate Element Analysis of Stitched Textile Composites
Glaessgen, E. H.; Raju, I. S.
2000-01-01
Three-dimensional effects related to the analysis of stitched textile composites are discussed. The method of calculation is based on the virtual crack closure technique (VCCT), and models that model the upper and lower surface of the delamination or debond with two-dimensional (2D) plate elements rather than three-dimensional (3D) solid elements. The major advantages of the plate element modeling technique are a smaller model size and simpler geometric modeling. Details of the modeling of the laminated plate and the stitching are discussed.
Scott Swartz; Matthew Seabaugh; William Dawson; Harlan Anderson; Tim Armstrong; Michael Cobb; Kirby Meacham; James Stephan; Russell Bennett; Bob Remick; Chuck Sishtla; Scott Barnett; John Lannutti
2004-06-12
This report summarizes the results of a four-year project, entitled, ''Low-Cost Manufacturing Of Multilayer Ceramic Fuel Cells'', jointly funded by the U.S. Department of Energy, the State of Ohio, and by project participants. The project was led by NexTech Materials, Ltd., with subcontracting support provided by University of Missouri-Rolla, Michael A. Cobb & Co., Advanced Materials Technologies, Inc., Edison Materials Technology Center, Gas Technology Institute, Northwestern University, and The Ohio State University. Oak Ridge National Laboratory, though not formally a subcontractor on the program, supported the effort with separate DOE funding. The objective of the program was to develop advanced manufacturing technologies for making solid oxide fuel cell components that are more economical and reliable for a variety of applications. The program was carried out in three phases. In the Phase I effort, several manufacturing approaches were considered and subjected to detailed assessments of manufacturability and development risk. Estimated manufacturing costs for 5-kW stacks were in the range of $139/kW to $179/kW. The risk assessment identified a number of technical issues that would need to be considered during development. Phase II development work focused on development of planar solid oxide fuel cell elements, using a number of ceramic manufacturing methods, including tape casting, colloidal-spray deposition, screen printing, spin-coating, and sintering. Several processes were successfully established for fabrication of anode-supported, thin-film electrolyte cells, with performance levels at or near the state-of-the-art. The work in Phase III involved scale-up of cell manufacturing methods, development of non-destructive evaluation methods, and comprehensive electrical and electrochemical testing of solid oxide fuel cell materials and components.
Polido Legaria, Elizabeth; Rocha, Joao; Tai, Cheuk-Wai; Kessler, Vadim G.; Seisenbaeva, Gulaim A.
2017-03-01
Due to the increasing demand of Rare Earth Elements (REE or RE), new and more efficient techniques for their extraction are necessary, suitable for both mining and recycling processes. Current techniques such as solvent extraction or solid adsorbents entail drawbacks such as using big volumes of harmful solvents or limited capacity. Hybrid nanoadsorbents based on SiO2 and highly stable γ-Fe2O3-SiO2 nanoparticles, proved recently to be very attractive for adsorption of REE, yet not being the absolute key to solve the problem. In the present work, we introduce a highly appealing new approach in which the nanoparticles, rather than behaving as adsorbent materials, perform as inducers of crystallization for the REE in the form of hydroxides, allowing their facile and practically total removal from solution. This induced crystallization is achieved by tuning the pH, offering an uptake efficiency more than 20 times higher than previously reported (up to 900 mg RE3+/g vs. 40 mg RE3+/g). The obtained phases were characterized by SEM-EDS, TEM, STEM and EFTEM and 13C and 29Si solid state NMR. Magnetic studies showed that the materials possessed enough magnetic properties to be easily removed by a magnet, opening ways for an efficient and industrially applicable separation technique.
Leavesley, Silas; Bayraktar, Bülent; Venkatapathi, Murugesan; Hirleman, E. Dan; Bhunia, Arun K.; Robinson, J. Paul; Hassler, Richard; Smith, Linda; Rajwa, Bartek
2007-02-01
Traditional biological and chemical methods for pathogen identification require complicated sample preparation for reliable results. Optical scattering technology has been used for identification of bacterial cells in suspension, but with only limited success. Our published reports have demonstrated that scattered light based identification of Listeria colonies growing on solid surfaces is feasible with proper pattern recognition tools. Recently we have extended this technique to classification of other bacterial genera including, Salmonella, Bacillus, and Vibrio. Our approach may be highly applicable to early detection and classification of pathogens in food-processing industry and in healthcare. The unique scattering patterns formed by colonies of different species are created through differences in colony microstructure (on the order of wavelength used), bulk optical properties, and the macroscopic morphology. While it is difficult to model the effect on scatter-signal patterns owing to the microstructural changes, the influence of bulk optical properties and overall shape of colonies can be modeled using geometrical optics. Our latest research shows that it is possible to model the scatter pattern of bacterial colonies using solid-element optical modeling software (TracePro), and theoretically assess changes in macro structure and bulk refractive indices. This study allows predicting the theoretical limits of resolution and sensitivity of our detection and classification methods. Moreover, quantification of changes in macro morphology and bulk refractive index provides an opportunity to study the response of colonies to various reagents and antibiotics.
Solid Propellant Grain Structural Integrity Analysis
1973-01-01
The structural properties of solid propellant rocket grains were studied to determine the propellant resistance to stresses. Grain geometry, thermal properties, mechanical properties, and failure modes are discussed along with design criteria and recommended practices.
STARS: A general-purpose finite element computer program for analysis of engineering structures
Gupta, K. K.
1984-01-01
STARS (Structural Analysis Routines) is primarily an interactive, graphics-oriented, finite-element computer program for analyzing the static, stability, free vibration, and dynamic responses of damped and undamped structures, including rotating systems. The element library consists of one-dimensional (1-D) line elements, two-dimensional (2-D) triangular and quadrilateral shell elements, and three-dimensional (3-D) tetrahedral and hexahedral solid elements. These elements enable the solution of structural problems that include truss, beam, space frame, plane, plate, shell, and solid structures, or any combination thereof. Zero, finite, and interdependent deflection boundary conditions can be implemented by the program. The associated dynamic response analysis capability provides for initial deformation and velocity inputs, whereas the transient excitation may be either forces or accelerations. An effective in-core or out-of-core solution strategy is automatically employed by the program, depending on the size of the problem. Data input may be at random within a data set, and the program offers certain automatic data-generation features. Input data are formatted as an optimal combination of free and fixed formats. Interactive graphics capabilities enable convenient display of nodal deformations, mode shapes, and element stresses.
Model Reduction in Dynamic Finite Element Analysis of Lightweight Structures
Flodén, Ola; Persson, Kent; Sjöström, Anders
2012-01-01
The application of wood as a construction material when building multi-storey buildings has many advantages, e.g., light weight, sustainability and low energy consumption during the construction and lifecycle of the building. However, compared to heavy structures, it is a greater challenge to build...... lightweight structures without noise and disturbing vibrations between storeys and rooms. The dynamic response of floor and wall structures may be investigated using finite element models with three-dimensional solid elements [1]. In order to analyse the global response of complete buildings, finite element...
PROBABILISTIC FINITE ELEMENT ANALYSIS OF VERTEBRAE OF THE LUMBAR SPINE UNDER HYPEREXTENSION LOADING
M.M. Rahman
2011-06-01
Full Text Available The major goal of this study is to determine the stress on vertebrae subjected to hyperextension loading. In addition, probabilistic analysis was adopted in finite element analysis (FEA to verify the parameters that affected failure. Probabilistic finite element (PFE analysis plays an important role today in solving engineering problems in many fields of science and industry and has recently been applied in orthopaedic applications. A finite element model of the L2 vertebra was constructed in SolidWorks and imported by ANSYS 11.0 software for the analysis. For simplicity, vertebra components were modelled as isotropic and linear materials. A tetrahedral solid element was chosen as the element type because it is better suited to and more accurate in modelling problems with curved boundaries such as bone. A Monte Carlo simulation (MCS technique was performed to conduct the probabilistic analysis using a built-in probabilistic module in ANSYS with 100 samples. It was found that the adjacent lower pedicle region depicted the highest stress with 1.21 MPa, and the probability of failure was 3%. The force applied to the facet (FORFCT variable needs to be emphasized after sensitivity assessment revealed that this variable is very sensitive to the stress and displacement output parameters.
Rotordynamic Analysis with Shell Elements for the Transfer Matrix Method
1989-08-01
jACCESSION NO. 11. TITLE (Include Security Classification) (UNCLASSIFIED) ROTORDYNAMIC ANALYSIS WITH SHELL ELEMENTS FOR THE TRANSFER MATRIX METHOD 12...SECURITY CLASSIFICATION OF THIS PAGE AFIT/CI "OVERPRINT" iii ABSTRACT Rotordynamic Analysis with Shell Elements for the Transfer Matrix Method. (August...analysts in indus- try . ’ . ," Accesiu:, For NTIS CR,4i Fi FilC TA,: [3 0. fi A-1 B I ., ,.................. ,., ROTORDYNAMIC ANALYSIS WITH SHELL ELEMENTS
Finite Element Vibration Analysis of Beams, Plates and Shells
Jaroslav Mackerle
1999-01-01
Full Text Available This bibliography lists references to papers, conference proceedings and theses/dissertations dealing with finite element vibration analysis of beams, plates and shells that were published in 1994–1998. It contains 361 citations. Also included, as separated subsections, are vibration analysis of composite materials and vibration analysis of structural elements with cracks/contacts.
Error computation for adaptive finite element analysis
Khan, A A; Memon, I R; Ming, X Y
2002-01-01
The paper gives a simple numerical procedure for computations of errors generated by the discretisation process of finite element method. The procedure given is based on the ZZ error estimator which is believed to be reasonable accurate and thus can be readily implemented in any existing finite element codes. The devised procedure not only estimates the global energy norm error but also evaluates the local errors in individual elements. In the example, the given procedure is combined with an adaptive refinement procedure, which provides guidance for optimal mesh designing and allows the user to obtain a desired accuracy with a limited number of interaction. (author)
Ring-element analysis of layered orthotropic bodies
Jørgensen, O.
1993-01-01
to be determined in the finite element analysis. The element chosen is an eight node isoparametric element of the serendipity family. The Fourier series show very high rate of convergence for the problems solved. The investigation shows that the computational work is remarkably reduced in relation...
Finite element analysis theory and application with ANSYS
Moaveni, Saeed
2015-01-01
For courses in Finite Element Analysis, offered in departments of Mechanical or Civil and Environmental Engineering. While many good textbooks cover the theory of finite element modeling, Finite Element Analysis: Theory and Application with ANSYS is the only text available that incorporates ANSYS as an integral part of its content. Moaveni presents the theory of finite element analysis, explores its application as a design/modeling tool, and explains in detail how to use ANSYS intelligently and effectively. Teaching and Learning Experience This program will provide a better teaching and learning experience-for you and your students. It will help: *Present the Theory of Finite Element Analysis: The presentation of theoretical aspects of finite element analysis is carefully designed not to overwhelm students. *Explain How to Use ANSYS Effectively: ANSYS is incorporated as an integral part of the content throughout the book. *Explore How to Use FEA as a Design/Modeling Tool: Open-ended design problems help stude...
Ignition transient analysis of solid rocket motor
Han, Samuel S.
1991-01-01
Measurement data on the performance of Space Shuttle Solid Rocket Motor show wide variations in the head-end pressure changes and the total thrust build-up during the ignition transient periods. To analyze the flow and thermal behavior in the tested solid rocket motors, a 1-dimensional, ideal gas flow model via the SIMPLE algorithm was developed. Numerical results showed that burning patterns in the star-shaped head-end segment of the propellant and the erosive burning rate are two important factors controlling the ignition transients. The objective of this study is to extend the model to include the effects of aluminum particle commonly used in solid propellants. To treat the effects of aluminum-oxide particles in the combustion gas, conservation of mass, momentum, and energy equations for the particles are added in the numerical formulation and integrated by an inter-phase-slip algorithm.
Borst, H. V.
1978-01-01
A method is presented to design and predict the performance of axial flow rotors operating in a duct. The same method is suitable for the design of ducted fans and open propellers. The unified method is based on the blade element approach and the vortex theory for determining the three dimensional effects, so that two dimensional airfoil data can be used for determining the resultant force on each blade element. Resolution of this force in the thrust and torque planes and integration allows the total performance of the rotor, fan or propeller to be predicted. Three different methods of analysis, one based on a momentum flow theory; another on the vortex theory of propellers; and a third based on the theory of ducted fans, agree and reduce cascade airfoil data to single line as a function of the loading and induced angle of attack at values of constant inflow angle. The theory applies for any solidity from .01 to over 1 and any blade section camber. The effects of the duct and blade number can be determined so that the procedure applies over the entire range from two blade open propellers, to ducted helicopter tail rotors, to axial flow compressors with or without guide vanes, and to wind tunnel drive fans.
Trkmic, M. [University of Zagreb, Faculty of Mechanical Engineering and Naval Architecturek Zagreb (Croatia); Curkovic, L. [University of Zagreb, Faculty of Chemical Engineering and Technology, Zagreb (Croatia); Asperger, D. [HEP-Proizvodnja, Thermal Power Plant Department, Zagreb (Croatia)
2012-06-15
This paper deals with the development and validation of methods for identifying the composition of solid residue after liquid and solid fuel combustion in thermal power plant furnaces. The methods were developed for energy dispersive X-ray fluorescence (EDXRF) spectrometer analysis. Due to the fuels used, the different composition and the location of creation of solid residue, it was necessary to develop two methods. The first method is used for identifying solid residue composition after fuel oil combustion (Method 1), while the second method is used for identifying solid residue composition after the combustion of solid fuels, i. e. coal (Method 2). Method calibration was performed on sets of 12 (Method 1) and 6 (Method 2) certified reference materials (CRM). CRMs and analysis test samples were prepared in pellet form using hydraulic press. For the purpose of method validation the linearity, accuracy, precision and specificity were determined, and the measurement uncertainty of methods for each analyte separately was assessed. The methods were applied in the analysis of real furnace residue samples. (Copyright copyright 2012 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)
Trace elements in termites by PIXE analysis
Yoshimura, T.; Kagemori, N.; Kawai, S.; Sera, K.; Futatsugawa, S.
2002-04-01
Trace elements in a Japanese subterranean xylophagous termite, Coptotermes formosanus Shiraki, were analyzed by the PIXE method. The total amount of the 14 predominant elements out of 27 detected in an intact termite was higher in a soldier termite (23 000 μg/g) than in a worker termite (10 000 μg/g). A block of wood ( Pinus densiflora Sieb. et Zucc.) for termite feed had a much lower concentration (3600 μg/g) compared with that in an intact termite. This probably relates the functional bio-condensation and/or bio-recycling of trace elements in C. formosanus. When a termite was separated into three anatomical parts, head, degutted body and gut, the worker gut contained the highest total amount of the 14 predominant measured elements (31 000 μg/g). This might be correlated with the higher activity of food digestion and energy production in the worker gut. Moreover, the mandible of the soldier head, with an exoskeleton that is intensely hardened, showed a preferential distribution of Mn and Fe. These results suggest that the characteristic localization of elements will be closely related to the functional role of the individual anatomical part of C. formosanus.
Trace elements in termites by PIXE analysis
Yoshimura, T. E-mail: tsuyoshi@termite.kuwri.kyoto-u.ac.jp; Kagemori, N.; Kawai, S.; Sera, K.; Futatsugawa, S
2002-04-01
Trace elements in a Japanese subterranean xylophagous termite, Coptotermes formosanus Shiraki, were analyzed by the PIXE method. The total amount of the 14 predominant elements out of 27 detected in an intact termite was higher in a soldier termite (23 000 {mu}g/g) than in a worker termite (10 000 {mu}g/g). A block of wood (Pinus densiflora Sieb. et Zucc.) for termite feed had a much lower concentration (3600 {mu}g/g) compared with that in an intact termite. This probably relates the functional bio-condensation and/or bio-recycling of trace elements in C. formosanus. When a termite was separated into three anatomical parts, head, degutted body and gut, the worker gut contained the highest total amount of the 14 predominant measured elements (31 000 {mu}g/g). This might be correlated with the higher activity of food digestion and energy production in the worker gut. Moreover, the mandible of the soldier head, with an exoskeleton that is intensely hardened, showed a preferential distribution of Mn and Fe. These results suggest that the characteristic localization of elements will be closely related to the functional role of the individual anatomical part of C. formosanus.
Torsional inertia moment of beam element with complex section analysis based on FEM
Zhao An; Huang Jun; Lu Jianming
2012-01-01
Currently, for the analysis of complex bridge based on beam element, the calculation of cross-section torsional inertia moment is still an unresolved technical problem. Most current calculation of section torsional inertia moment is an approximate analytic method for two-dimensional cross-section, which is not fully consistent with the actual situation, and do not consider the effects of diaphragm in bridge. In order to analyze accurately cable-stayed bridge, suspension bridge and other complex bridge structures based on beam element, the calculation method of section torsional inertia moment based on finite element method （FEM） is invented in this paper. Firstly, setting up local cantilever fine model with solid element or shell element and applying torsion on the end of cantilever. Secondly, calculating the torsion angle of cantilever by FEM method and then the torsional moment through equivalent beam method. Finally, the examples of the section torsional moment calculation of concrete model with solid element with diaphragm and steel girder box model with shell element with diaphragm are used to verify the calculation method, which is applied to the suspension bridge design and construction control special software SBNA developed by Research Institute of Highway Ministry of Transport. Taizhou Bridge under construction is one of the examples.
Finite Element Analysis of Eutectic Structures
2014-03-12
by solid state sintering . The microstructure can exhibit many geometrical forms: dendritic, lamellar, and rods. The self-assembled structure can be...Thermal data was measured in the temperature range of 373 to 1273 K by the laser flash method (Anter Flashline 5000, Anter Corporation, Pittsburgh, PA...therefore is not believed to alter thermal measurements significantly. Specimens were also coated with carbon 4 paint in accordance with standard flash
J.O. Akinyele
2011-02-01
Full Text Available The complexity and conservative nature of the Yield Line Theory and its being an upper bound theory have made many design engineers to jettison the use of the analytical method in the analysis of slabs. Before now, the method has basically been a manual or hand methodwhich some engineers did not see a need for its use since there are many computer based packages in the analysis and design of slabs and other civil engineering structures. This paper presents a computer program that has adopted the yield line theory in the analysis of solid slabs. Two rectangular slabs of the same depth but differentdimensions were investigated. The Yield Line Theory was compared with two other analytical methods namely, Finite Element Method and Elastic Theory Method. The results obtained for a two-way spanning slab showed that the yield line theory is truly conservative, butincreasing the result by 25% caused the moment obtained to be very close to the results of the other two methods. Although it was still conservative, the check for deflections showed that it is reliable and economical in terms of reinforcement provision. For a one way spanning slab the results without any increment falls in between the two other methods with the Elastic method giving a conservative results. The paper concludes that the introduction of a computer-based yield line theory program will make the analytical method acceptable to design engineers in the developing countries of the world.
Comparison of boundary element and finite element methods in spur gear root stress analysis
Sun, H.; Mavriplis, D.; Huston, R. L.; Oswald, F. B.
1989-01-01
The boundary element method (BEM) is used to compute fillet stress concentration in spur gear teeth. The results are shown to compare favorably with analogous results obtained using the finite element method (FEM). A partially supported thin rim gear is studied. The loading is applied at the pitch point. A three-dimensional analysis is conducted using both the BEM and FEM (NASTRAN). The results are also compared with those of a two-dimensional finite element model. An advantage of the BEM over the FEM is that fewer elements are needed with the BEM. Indeed, in the current study the BEM used 92 elements and 270 nodes whereas the FEM used 320 elements and 2037 nodes. Moreover, since the BEM is especially useful in problems with high stress gradients it is potentially a very useful tool for fillet stress analyses.
Meima, J.A.; Comans, R.N.J.
1999-01-01
For a proper assessment of the environmental impact of the utilisation and disposal of Municipal Solid Waste Incinerator (MSWI) bottom ash it is necessary to understand weathering processes and their effects on (trace) element leaching. The authors have investigated the processes that control the le
Meima, J.A.; Comans, R.N.J.
1999-01-01
For a proper assessment of the environmental impact of the utilisation and disposal of Municipal Solid Waste Incinerator (MSWI) bottom ash it is necessary to understand weathering processes and their effects on (trace) element leaching. The authors have investigated the processes that control the le
Tadepalli, Srinivas C; Erdemir, Ahmet; Cavanagh, Peter R
2011-08-11
Finite element analysis has been widely used in the field of foot and footwear biomechanics to determine plantar pressures as well as stresses and strains within soft tissue and footwear materials. When dealing with anatomical structures such as the foot, hexahedral mesh generation accounts for most of the model development time due to geometric complexities imposed by branching and embedded structures. Tetrahedral meshing, which can be more easily automated, has been the approach of choice to date in foot and footwear biomechanics. Here we use the nonlinear finite element program Abaqus (Simulia, Providence, RI) to examine the advantages and disadvantages of tetrahedral and hexahedral elements under compression and shear loading, material incompressibility, and frictional contact conditions, which are commonly seen in foot and footwear biomechanics. This study demonstrated that for a range of simulation conditions, hybrid hexahedral elements (Abaqus C3D8H) consistently performed well while hybrid linear tetrahedral elements (Abaqus C3D4H) performed poorly. On the other hand, enhanced quadratic tetrahedral elements with improved stress visualization (Abaqus C3D10I) performed as well as the hybrid hexahedral elements in terms of contact pressure and contact shear stress predictions. Although the enhanced quadratic tetrahedral element simulations were computationally expensive compared to hexahedral element simulations in both barefoot and footwear conditions, the enhanced quadratic tetrahedral element formulation seems to be very promising for foot and footwear applications as a result of decreased labor and expedited model development, all related to facilitated mesh generation.
Analysis on 9 Elements in English Pragmatics
李霞
2014-01-01
College Students may have no troubles to compose grammatically correct sentences to express themselves,but sometimes the sentences just seem not pragmatically proper.Through analyzing and comprehending the 9 Elements in English Pragmatics to avoid the misunderstanding and misusing in the communication is significant for English learners,special to one who intends to use English as a communicating medium.
Analysis on the Three Elements in Communication
李霞
2014-01-01
In public communication,people may have no troubles to epress themselves grammatically correctly,but sometimes the sentences just sound not pragmatically proper.Through analyzing and comprehending those Elements in English to avoid the misunderstanding and misusing in the communication is significant.
Effective Finite Elements for Shell Analysis.
1984-02-20
conjunction with a shallow shell theory . It 2 should be noteJ that contrary to the results of earlier investigators [12,19], use of a shallow shell theory in...the inadequacy of the shallow shell theory for the relatively deep element emerging from such a coarse mesh. A considerable improvement is obtained
Magnetic Solid Phase Extraction Applied to Food Analysis
Israel S. Ibarra
2015-01-01
Full Text Available Magnetic solid phase extraction has been used as pretreatment technique for the analysis of several compounds because of its advantages when it is compared with classic methods. This methodology is based on the use of magnetic solids as adsorbents for preconcentration of different analytes from complex matrices. Magnetic solid phase extraction minimizes the use of additional steps such as precipitation, centrifugation, and filtration which decreases the manipulation of the sample. In this review, we describe the main procedures used for synthesis, characterization, and application of this pretreatment technique which were applied in food analysis.
Phosphogypsum analysis: total content and extractable element concentrations
Gennari, Roseli F.; Medina, Nilberto H., E-mail: rgennari@dfn.if.usp.br, E-mail: medina@if.usp.br [Departamento de Fisica Nuclear, Instituto de Fisica (USP), Sao Paulo, SP (Brazil); Garcia, Isabella; Silveira, Marcilei A.G., E-mail: shila@if.usp.br [Centro Universitario da FEI. Sao Bernardo do Campo, SP (Brazil)
2011-07-01
Phosphogypsum stand for the chemical origin gypsum generated in fertilizers production, in which phosphate rock is attacked by sulfuric acid resulting in phosphoric acid (H{sub 3}PO{sub 4}) and phosphate fertilizers. Phosphogypsum is not a commercial product and it is stocked in large open areas or accumulated in lakes inducing to a major environmental problem due to the presence of toxic and radioactive elements. The increasing world agricultural demand is the real responsible for the severity of this environmental problem. Nevertheless, there are some possibilities for the application of this reject material, such as civil construction, waste water treatment, and in cultivated lands, etc. In the agriculture the phosphogypsum is commonly used as a nutrient source due to its large amounts of phosphorus, calcium and sulfur. However, there are still some environmental questions related to the use of this by-product since phosphogypsum is classified as TENORM (Technologically Enhanced Naturally Occurring Radioactive Material), which is a solid waste containing heavy metals and naturally occurring radioactive elements from the rock matrix. In this work, Plasma Mass Spectrometry (ICP-MS) was used to study phosphogypsum samples. Several acid solutions for samples digestion were evaluated in order to be feasible the chemical analysis. BCR sequential extractions were also performed. The results showed analyte concentrations are highly dependent on the acid solution used. The BCR guidelines could not be applied as used for soil, since the phosphogypsum solubility is different. So, it would be necessary to use different mass aliquots in the extractions, to be feasible an environmental evaluation. (author)
VIRTUAL EXPERIMENTAL ANALYSIS ON CLEANING ELEMENT OF SUGARCANE HARVESTER
Ma Fanglan; Li Shangping; He Yulin; Meng Yanmei; Chen Weixu
2005-01-01
The laws of influence of different factors have been analyzed in order to enhance the working efficiency and fatigue life of the cleaning element in brush shape of the sugarcane harvester.Based on the principle of orthogonal experiment design, the virtual-orthogonal-experimental analysis for the cleaning element is carried out on the finite element analysis (FEA) software-ANSYS after analyzing the nonlinear structural behavior in the working procedure. The results are analyzed with the overall balancing method, and then the optimal combination is got, which is made up of different levels of different factors. Also the optimal combination of design parameters of the cleaning element received from the virtual experimental analysis is conducted an experiment to confirm that the virtual analysis model and results are right, and the effect of factors on the function of the cleaning element is obtained by more analysis and further optimizing.
Numerical Analysis of Solids at Failure
2011-08-20
specimen follows an elastoplastic model (finite strain J2 theory), with the shear band/crack being propagated based on the loss of ellipticity criterion of...cohesive law along the propagating crack. A power law with damage is considered. Figure 9.b shows the deformed configuration computed with a mesh of 6...integration in nonlinear dynamics of elastoplastic solids were prepared during this project, based on our previous work with AFOSR. Final Report, FA9550-08-1
A Dual Super-Element Domain Decomposition Approach for Parallel Nonlinear Finite Element Analysis
Jokhio, G. A.; Izzuddin, B. A.
2015-05-01
This article presents a new domain decomposition method for nonlinear finite element analysis introducing the concept of dual partition super-elements. The method extends ideas from the displacement frame method and is ideally suited for parallel nonlinear static/dynamic analysis of structural systems. In the new method, domain decomposition is realized by replacing one or more subdomains in a "parent system," each with a placeholder super-element, where the subdomains are processed separately as "child partitions," each wrapped by a dual super-element along the partition boundary. The analysis of the overall system, including the satisfaction of equilibrium and compatibility at all partition boundaries, is realized through direct communication between all pairs of placeholder and dual super-elements. The proposed method has particular advantages for matrix solution methods based on the frontal scheme, and can be readily implemented for existing finite element analysis programs to achieve parallelization on distributed memory systems with minimal intervention, thus overcoming memory bottlenecks typically faced in the analysis of large-scale problems. Several examples are presented in this article which demonstrate the computational benefits of the proposed parallel domain decomposition approach and its applicability to the nonlinear structural analysis of realistic structural systems.
Ko, William L.; Olona, Timothy; Muramoto, Kyle M.
1990-01-01
Different finite element models previously set up for thermal analysis of the space shuttle orbiter structure are discussed and their shortcomings identified. Element density criteria are established for the finite element thermal modelings of space shuttle orbiter-type large, hypersonic aircraft structures. These criteria are based on rigorous studies on solution accuracies using different finite element models having different element densities set up for one cell of the orbiter wing. Also, a method for optimization of the transient thermal analysis computer central processing unit (CPU) time is discussed. Based on the newly established element density criteria, the orbiter wing midspan segment was modeled for the examination of thermal analysis solution accuracies and the extent of computation CPU time requirements. The results showed that the distributions of the structural temperatures and the thermal stresses obtained from this wing segment model were satisfactory and the computation CPU time was at the acceptable level. The studies offered the hope that modeling the large, hypersonic aircraft structures using high-density elements for transient thermal analysis is possible if a CPU optimization technique was used.
Finite element analysis of human joints
Bossart, P.L.; Hollerbach, K.
1996-09-01
Our work focuses on the development of finite element models (FEMs) that describe the biomechanics of human joints. Finite element modeling is becoming a standard tool in industrial applications. In highly complex problems such as those found in biomechanics research, however, the full potential of FEMs is just beginning to be explored, due to the absence of precise, high resolution medical data and the difficulties encountered in converting these enormous datasets into a form that is usable in FEMs. With increasing computing speed and memory available, it is now feasible to address these challenges. We address the first by acquiring data with a high resolution C-ray CT scanner and the latter by developing semi-automated method for generating the volumetric meshes used in the FEM. Issues related to tomographic reconstruction, volume segmentation, the use of extracted surfaces to generate volumetric hexahedral meshes, and applications of the FEM are described.
Thermal Analysis of Thin Plates Using the Finite Element Method
Er, G. K.; Iu, V. P.; Liu, X. L.
2010-05-01
The isotropic thermal plate is analyzed with finite element method. The solution procedure is presented. The elementary stiffness matrix and loading vector are derived rigorously with variation principle and the principle of minimum potential energy. Numerical results are obtained based on the derived equations and tested with available exact solutions. The problems in the finite element analysis are figured out. It is found that the finite element solutions can not converge as the number of elements increases around the corners of the plate. The derived equations presented in this paper are fundamental for our further study on more complicated thermal plate analysis.
Arrieta, Edel
Additive manufacturing permits the fabrication of cellular metals which are materials that can be highly customizable and possess multiple and extraordinary properties such as damage tolerance, metamorphic and auxetic behaviors, and high specific stiffness. This makes them the subject of interest for innovative applications. With interest in these materials for energy absorption applications, this work presents the development of nonlinear finite element models in commercial software platforms (MSC Patran/Nastran) that permit the analysis of the deformation mechanisms of these materials under compressive loads. In the development of these models, a detailed multiscale study on the different factors affecting the response of cellular metals was conducted with the objective to understanding the physics with the objective of selecting the most appropriate experiments. In that manner, a series of experiments were conducted on Ti-6Al-4V specimens fabricated by electron beam melting at different manufacturing orientations. Digital image correlation was presented as a vital tool for the measurement of strains in specimens with complex shapes; the experiments contemplated compression and tension tests of Ti-6Al-4V solid components, as well as compression tests on cellular lattices of the same alloy. FEMs were developed from the same CAD file utilized for the fabrication of the lattices; in addition, different meshing approaches and mesh convergence analysis were discussed. The mesh density showed convergence in models with over 70,000 elements, permitting the evaluation of the stress/strain-distribution mechanisms in the lattices. However, because of the considerable variability of the experimental material properties, some numerical results showed significant errors in predicting the compressive force applied to the lattices during the experiments; thus suggesting the need to improve the quality control in the manufacturing process and develop better technologies in
Jacek Giersz
2015-05-01
Full Text Available A method for conducting fast and efficient gas chromatography based on short multicapillaries in straight alignment combined with atomic emission detection was developed for field analysis. The strategy enables for speciation analysis of organometallic compounds. The analytes are simultaneously ethylated and preconcentrated on a solid phase microextraction (SPME fiber placed in the headspace over the sample for 25 min. The ethylated species are then completely separated and selectively quantified within 25 s under isothermal conditions. A new miniaturized speciation analyzer has been constructed and evaluated. The system consists of a GC injection port and a lab-made miniaturized GC unit directly coupled with miniaturized plasma excitation source. The emitted light is transferred via optical fiber and registered with a miniaturized charged coupled device (CCD based spectrometer. Working parameters for multicapillary column gas chromatography with atomic emission detector, including carrier gas flow rate, desorption temperature, and GC column temperature, were optimized to achieve good separation of analytes. Basic investigations of the fundamental properties of 5 cm-long multicapillary column, to evaluate its potential and limitations as a rapid separation unit, are presented. The adaptation of the technique for use with a SPME system and with a multichannel element-selective plasma-emission detector is highlighted.
Xiaoyong, Bai; Yingbo, He; Chengjun, Chen
2010-06-01
In order to make it easier to extend an finite element software framework with contact implementation for transient solid dynamic analysis, we have designed a general-purposed framework-oriented parallel contact class in this article. A parallel contact computation algorithm model has been generated based on contact schemes reported on last two decades. The class is integrated to an open source platform easily without affecting the rest code of the platform.
X-Ray fluorescence analysis of trace elements in fruit juice
Bao, Sheng-Xiang; Wang, Zhi-Hong; Liu, Jing-Song
1999-12-01
X-Ray fluorescence spectrometry is applied to the determination of trace elements in fruit juice characterized by a high content of sugar and other soluble solid substances. Samples are prepared by evaporation, carbonization and pressing into discs. The synthesis of standards is described in detail. All element concentrations are directly estimated from linear calibration curves obtained without any matrix correction. The results of the analysis are in good agreement with those given by inductively coupled plasma-atomic emission spectrometry and atomic absorption spectrometry techniques.
Corotational formulation for 3d solids. An analysis of geometrically nonlinear foam deformation
Kaczmarczyk, Łukasz; Pearce, Chris J
2011-01-01
This paper presents theory for the Lagrange co-rotational (CR) formulation of finite elements in the geometrically nonlinear analysis of 3D structures. In this paper strains are assumed to be small while the magnitude of rotations from the reference configuration is not restricted. A new best fit rotator and consistent spin filter are derived. Lagrange CR formulation is applied with Hybrid Trefftz Stress elements, although presented methodology can be applied to arbitrary problem formulation and discretization technique, f.e. finite volume methods and lattice models, discreet element methods. Efficiency of CR formulation can be utilized in post-buckling stability analysis, damage and fracture mechanics, modelling of dynamic fragmentation of bodies made from quasi-brittle materials, solid fluid interactions and analysis of post-stressed structures, discreet body dynamics.
Finite Element Method for Analysis of Material Properties
Rauhe, Jens Christian
description of the material microstructure the finite element models must contain a large number of elements and this problem is solved by using the preconditioned conjugated gradient solver with an Element-By-Element preconditioner. Finite element analysis provides the volume averaged stresses and strains...... and the finite element method. The material microstructure of the heterogeneous material is non-destructively determined using X-ray microtomography. A software program has been generated which uses the X-ray tomographic data as an input for the mesh generation of the material microstructure. To obtain a proper...... which are used for the determination of the effective properties of the heterogeneous material. Generally, the properties determined using the finite element method coupled with X-ray microtomography are in good agreement with both experimentally determined properties and properties determined using...
A hybrid transfinite element approach for nonlinear transient thermal analysis
Tamma, Kumar K.; Railkar, Sudhir B.
1987-01-01
A new computational approach for transient nonlinear thermal analysis of structures is proposed. It is a hybrid approach which combines the modeling versatility of contemporary finite elements in conjunction with transform methods and classical Bubnov-Galerkin schemes. The present study is limited to nonlinearities due to temperature-dependent thermophysical properties. Numerical test cases attest to the basic capabilities and therein validate the transfinite element approach by means of comparisons with conventional finite element schemes and/or available solutions.
Analysis of the solid waste management of Guacimo, Costa Rica
Campos-Rodríguez, Rooel; Soto-Córdoba, Silvia
2014-01-01
The aim of this paper its shows the results about the analysis of the solid waste management in the “Municipalidad of Guacimo” located in Limón, Costa Rica. The Municipalidad of Guacimo doesn’t have the basic records and enough information that is necessary for improve the management of the solid waste. Because of that, this investigation provides the inputs for begin to design the solid waste management for the Municipalidad of Guacimo. We search quotes bibliographic about the situation and ...
Finite element analysis of damage in pipeline bends
Swart, A.E.; Karamanos, S.A.; Scarpas, A.; Blaauwendraad, J.
2010-01-01
The present paper describes a numerical formulation for the analysis of damage in steel pipeline bends. In particular, the numerical implementation of Gurson plasticity model is described in the framework of a special element, referred to as “tube element”. This is a three-node element, which simula
Analysis of automotive liftgate seals using finite element analysis
Rafael H. T Ueda
2010-01-01
Full Text Available Seals have wide application in automotive products. They are responsible for sealing the car in several parts such as the doors, the air intake cowl seal, and air intake lights seal. Strain and stress studies are very important in order to understand the behavior of polymeric materials, which are generally submitted to great workload variation and environmental influence. This study of EPDM rubber was carried out to define the strain, stress and yield stress. Tensile and compression tests were carried out on workpieces with 100 mm of length. The data were acquired using the Qmat software. A Finite Element Analysis using the MSC Marc MentatTM was conducted and compared with experimental tests. The results showed an increase of effort proportional to bulb thickness. The proportional increase of compression effort for different displacements was significant. Moreover, physical parameters such as length, thickness, and friction coefficient changed the strain and stress rate.
Nonlinear Finite Element Analysis of Sloshing
Siva Srinivas Kolukula
2013-01-01
Full Text Available The disturbance on the free surface of the liquid when the liquid-filled tanks are excited is called sloshing. This paper examines the nonlinear sloshing response of the liquid free surface in partially filled two-dimensional rectangular tanks using finite element method. The liquid is assumed to be inviscid, irrotational, and incompressible; fully nonlinear potential wave theory is considered and mixed Eulerian-Lagrangian scheme is adopted. The velocities are obtained from potential using least square method for accurate evaluation. The fourth-order Runge-Kutta method is employed to advance the solution in time. A regridding technique based on cubic spline is employed to avoid numerical instabilities. Regular harmonic excitations and random excitations are used as the external disturbance to the container. The results obtained are compared with published results to validate the numerical method developed.
Masson, Pierre, E-mail: masson@bordeaux.inra.fr
2014-12-01
Plants take up and store elements according to the environment in which they are growing. Because plants are at the base of the food chain, the determination of essential elements or toxic elements in plant materials is of importance. However, it is assumed that the element content determined on selected tissues may provide more specific information than that derived from the whole plant analysis. In this work, we assessed the feasibility of solid sampling–electrothermal vaporization–inductively coupled plasma-optical emission spectrometry analyses for quantitative imaging of Cd and Mg in plant leaves. Leaves of tobacco (Nicotiana tabacum) were selected to be used as samples. To produce a two dimensional image, sections cut from leaf samples were analyzed. Cellulose doped with multi-element solution standards was used as calibration samples. Two certified reference materials (NIST SRM 1547 Peach Leaves and NIST SRM 1573a Tomato leaves) were used to verify the accuracy of measurements with good agreement between the measured concentrations and the certified values. Quantitative imaging revealed the inhomogeneous distribution of the selected elements. Excess of Cd and Mg tended to be focused on peripheral regions and the tip of the leaf.
Stress analysis of 3D complex geometries using the scaled boundary polyhedral finite elements
Talebi, Hossein; Saputra, Albert; Song, Chongmin
2016-10-01
While dominating the numerical stress analysis of solids, the finite element method requires a mesh to conform to the surface of the geometry. Thus the mesh generation of three dimensional complex structures often require tedious human interventions. In this paper, we present a formulation for arbitrary polyhedral elements based on the scaled boundary finite element method, which reduces the difficulties in automatic mesh generation. We also propose a simple method to generate polyhedral meshes with local refinements. The mesh generation method is based on combining an octree mesh with surfaces defined using signed distance functions. Through several numerical examples, we verify the results, study the convergence behaviour and depict the many advantages and capabilities of the presented method. This contribution is intended to assist us to eventually frame a set of numerical methods and associated tools for the full automation of the engineering analysis where minimal human interaction is needed.
Introduction to finite element analysis using MATLAB and Abaqus
Khennane, Amar
2013-01-01
There are some books that target the theory of the finite element, while others focus on the programming side of things. Introduction to Finite Element Analysis Using MATLAB(R) and Abaqus accomplishes both. This book teaches the first principles of the finite element method. It presents the theory of the finite element method while maintaining a balance between its mathematical formulation, programming implementation, and application using commercial software. The computer implementation is carried out using MATLAB, while the practical applications are carried out in both MATLAB and Abaqus. MA
Finite Element Analysis of Fluid-Conveying Timoshenko Pipes
Chih-Liang Chu
1995-01-01
Full Text Available A general finite element formulation using cubic Hermitian interpolation for dynamic analysis of pipes conveying fluid is presented. Both the effects of shearing deformations and rotary inertia are considered. The development retains the use of the classical four degrees-of-freedom for a two-node element. The effect of moving fluid is treated as external distributed forces on the support pipe and the fluid finite element matrices are derived from the virtual work done due to the fluid inertia forces. Finite element matrices for both the support pipe and moving fluid are derived and given explicitly. A numerical example is given to demonstrate the validity of the model.
A suitable low-order, eight-node tetrahedral finite element for solids
Key, S.W.; Heinstein, M.S.; Stone, C.M.; Mello, F.J.; Blanford, M.L.; Budge, K.G.
1998-03-01
To use the all-tetrahedral mesh generation existing today, the authors have explored the creation of a computationally efficient eight-node tetrahedral finite element (a four-node tetrahedral finite element enriched with four mid-face nodal points). The derivation of the element`s gradient operator, studies in obtaining a suitable mass lumping, and the element`s performance in applications are presented. In particular they examine the eight-node tetrahedral finite element`s behavior in longitudinal plane wave propagation, in transverse cylindrical wave propagation, and in simulating Taylor bar impacts. The element samples only constant strain states and, therefore, has 12 hour-glass modes. In this regard it bears similarities to the eight-node, mean-quadrature hexahedral finite element. Comparisons with the results obtained from the mean-quadrature eight-node hexahedral finite element and the four-node tetrahedral finite element are included. Given automatic all-tetrahedral meshing, the eight-node, constant-strain tetrahedral finite element is a suitable replacement for the eight-node hexahedral finite element in those cases where mesh generation requires an inordinate amount of user intervention and direction to obtain acceptable mesh properties.
An Integrated Approach to Thermal Analysis of Pharmaceutical Solids
Riley, Shelley R. Rabel
2015-01-01
A three-tiered experiment for undergraduate Instrumental Analysis students is presented in which students characterize the solid-state thermal behavior of an active pharmaceutical ingredient (acetaminophen) and excipient (a-lactose hydrate) using differential scanning calorimetry, thermogravimetric analysis, and thermal microscopy. Students are…
An Integrated Approach to Thermal Analysis of Pharmaceutical Solids
Riley, Shelley R. Rabel
2015-01-01
A three-tiered experiment for undergraduate Instrumental Analysis students is presented in which students characterize the solid-state thermal behavior of an active pharmaceutical ingredient (acetaminophen) and excipient (a-lactose hydrate) using differential scanning calorimetry, thermogravimetric analysis, and thermal microscopy. Students are…
Finite element analysis of nonsmooth contact
Kane, C; Repetto, E. A.; Ortiz, M.; Marsden, J. E.
1999-01-01
This work develops robust contact algorithms capable of dealing with complex contact situations involving several bodies with corners. Amongst the mathematical tools we bring to bear on the problem is nonsmooth analysis, following Clarke (F.H. Clarke. Optimization and nonsmooth analysis. John Wiley and Sons, New York, 1983.). We specifically address contact geometries for which both the use of normals and gap functions have difficulties and therefore precludes the application of most contact ...
Finite Element Method for Analysis of Material Properties
Rauhe, Jens Christian
The use of cellular and composite materials have in recent years become more and more common in all kinds of structural components and accurate knowledge of the effective properties is therefore essential. In this wok the effective properties are determined using the real material microstructure...... and the finite element method. The material microstructure of the heterogeneous material is non-destructively determined using X-ray microtomography. A software program has been generated which uses the X-ray tomographic data as an input for the mesh generation of the material microstructure. To obtain a proper...... description of the material microstructure the finite element models must contain a large number of elements and this problem is solved by using the preconditioned conjugated gradient solver with an Element-By-Element preconditioner. Finite element analysis provides the volume averaged stresses and strains...
Vehicle Interior Noise Prediction Using Energy Finite Element Analysis Project
National Aeronautics and Space Administration — It is proposed to develop and implement a computational technique based on Energy Finite Element Analysis (EFEA) for interior noise prediction of advanced aerospace...
Hua Tan; Fengying Zhang; Jing Chen; Xin Lin; Weidong Huang
2011-01-01
@@ Morphology evolution of prior β grains of laser solid forming (LSF) Ti-xAl-yV (x ≤ 11,y ≤ 20) alloys from blended elemental powders is investigated.The formation mechanism of grain morphology is revealed by incorporating columnar to equiaxed transition (CET) mechanism during solidification.%Morphology evolution of prior β grains of laser solid forming (LSF) Ti-xAl-yV (x ≤ 11,y ≤ 20) alloys from blended elemental powders is investigated. The formation mechanism of grain morphology is revealed by incorporating columnar to equiaxed transition (CET) mechanism during solidification. The morphology of prior β grains of LSF Ti-6Al-yV changes from columnar to equiaxed grains with increasing element V content from 4 to 20 wt.-％. This agrees well with CET theoretical prediction. Likewise, the grain morphology of LSF Ti-xA1-2V from blended elemental powders changes from large columnar to small equiaxed with increasing A1 content from 2 to 11 wt.-％. The macro-morphologies of LSF Ti-8A1-2V and Ti-11A1-2V from blended elemental powders do not agree with CET predictions. This is caused by the increased disturbance effects of mixing enthalpy with increasing A1 content, generated in the alloying process of Ti, Al, and V in the molten pool.
Nannoni, Francesco; Santolini, Riccardo; Protano, Giuseppe
2015-09-01
This paper presents the results of a biomonitoring study to evaluate the environmental impact of airborne emissions from a municipal solid waste landfill in central Italy. Concentrations of 11 heavy elements, as well as photosynthetic efficiency and cell membrane integrity were measured in Evernia prunastri lichens transplanted for 4months in 17 monitoring sites around the waste landfill. Heavy element contents were also determined in surface soils. Analytical data indicated that emissions from the landfill affected Cd, Co, Cr, Cu, Ni, Pb, Sb and Zn concentrations in lichens transplanted within the landfill and along the fallout direction. In these sites moderate to severe accumulation of these heavy elements in lichens was coupled with an increase in cell membrane damage and decrease in photosynthetic efficiency. Nevertheless, results indicated that landfill emissions had no relevant impact on lichens, as heavy element accumulation and weak stress symptoms were detected only in lichen transplants from sites close to solid waste. The appropriate management of this landfill poses a low risk of environmental contamination by heavy elements.
Karolewicz, Bozena; Górniak, Agata; Owczarek, Artur; Nartowski, Karol; Zurawska-Płaksej, Ewa; Pluta, Janusz
2012-01-01
In the first part of the article solid dispersions were classified the properties and methods of their preparation were described. This section presents methods of analysis of solid dispersions i.e.: thermoanalytical methods, XRPD, FTIR, microscopic methods, dissolution studies and examples of drug forms where solid dispersions were used.
Anisotropic Superconvergence Analysis for the Wilson Nonconforming Element
Shaochun Chen; Huixia Sun; Shipeng Mao
2006-01-01
The regular condition (there exists a constant c independent of the element K and the mesh such that hK/ρK ≤ c, where hK and ρK are diameters of K and the biggest ball contained in K, respectively) or the quasi-uniform condition is a basic assumption in the analysis of classical finite elements. In this paper, the supercloseness for consistency error and the superconvergence estimate at the central point of the element for the Wilson nonconforming element in solving second-order elliptic boundary value problem are given without the above assumption on the meshes. Furthermore the global superconvergence for the Wilson nonconforming element is obtained under the anisotropic meshes. Lastly, a numerical test is carried out which confirms our theoretical analysis.
Engineering and Design: Geotechnical Analysis by the Finite Element Method
2007-11-02
used it to determine stresses and movements in embank- ments, and Reyes and Deer described its application to analysis of underground openings in rock...3-D steady-state seepage analysis of permeability of the cutoff walls was varied from 10 to Cerrillos Dam near Ponce , Puerto Rico, for the U.S.-6 10...36 Hughes, T. J. R. (1987). The Finite Element Reyes , S. F., and Deene, D. K. (1966). “Elastic Method, Linear Static and Dynamic Finite Element
OBJECT-ORIENTED FINITE ELEMENT ANALYSIS AND PROGRAMMING IN VC + +
马永其; 冯伟
2002-01-01
The design of finite element analysis program using object-oriented programming(OOP) techniques is presented. The objects, classes and the subclasses used in theprogramming are explained. The system of classes library of finite element analysis programand Windows-type Graphical User Interfaces by VC + + and its MFC are developed. Thereliability, reusability and extensibility of program are enhanced. It is a reference todevelop the large-scale, versatile and powerful systems of object-oriented finite elementsoftware.
Finite element analysis to model complex mitral valve repair.
Labrosse, Michel; Mesana, Thierry; Baxter, Ian; Chan, Vincent
2016-01-01
Although finite element analysis has been used to model simple mitral repair, it has not been used to model complex repair. A virtual mitral valve model was successful in simulating normal and abnormal valve function. Models were then developed to simulate an edge-to-edge repair and repair employing quadrangular resection. Stress contour plots demonstrated increased stresses along the mitral annulus, corresponding to the annuloplasty. The role of finite element analysis in guiding clinical practice remains undetermined.
Determination of a synchronous generator characteristics via Finite Element Analysis
Kolondzovski Zlatko
2005-01-01
Full Text Available In the paper a determination of characteristics of a small salient pole synchronous generator (SG is presented. Machine characteristics are determined via Finite Element Analysis (FEA and for that purpose is used the software package FEMM Version 3.3. After performing their calculation and analysis, one can conclude that most of the characteristics presented in this paper can be obtained only by using the Finite Element Method (FEM.
An iterative algorithm for finite element analysis
Laouafa, F.; Royis, P.
2004-03-01
In this paper, we state in a new form the algebraic problem arising from the one-field displacement finite element method (FEM). The displacement approach, in this discrete form, can be considered as the dual approach (force or equilibrium) with subsidiary constraints. This approach dissociates the nonlinear operator to the linear ones and their sizes are linear functions of integration rule which is of interest in the case of reduced integration. This new form of the problem leads to an inexpensive improvement of FEM computations, which acts at local, elementary and global levels. We demonstrate the numerical performances of this approach which is independent of the mesh structure. Using the GMRES algorithm we build, for nonsymmetric problems, a new algorithm based upon the discretized field of strain. The new algorithms proposed are more closer to the mechanical problem than the classical ones because all fields appear during the resolution process. The sizes of the different operators arising in these new forms are linear functions of integration rule, which is of great interest in the case of reduced integration.
Chu, T M; Reddy, N P; Padovan, J
1995-07-01
An asymmetric 3-dimensional finite element model (FEM) of the ankle-foot orthosis (AFO) together with the ankle-foot complex was developed using the computer aided design (CAD) program PATRAN. Static analysis of normal and pathological motions of the ankle-foot complex such as the "drop-foot" problem were conducted using the FEM program ADINA. A total of 313 three dimensional solid elements and 10 truss elements were used. Heel strike and toe-off condition were simulated. Results revealed that the peak compressive stress (1.6 MPa) in the AFO model occurred in the heel regions of the AFO and the maximum tensile stress (0.8 MPa) occurred in the neck region of the AFO during toe-off. Parametric analyses revealed that the model was sensitive to the elastic moduli of the AFO and of the soft tissue, but was relatively insensitive to the ligament stiffness. The results confirmed the hypothesis that peak stresses in the orthosis occur in the heal and neck regions of the orthosis.
无
2003-01-01
A novel type of solid-phase extraction element named"Magic Chemisorber" is developed for sorptive enrichment of dilute analytes from aqueous samples with high extraction efficiencies due to its capacious layer of sorbent polydimethylsiloxane.This extraction element combined with thermal desorption-gas chromatography/mass spectrometry using a pyrolysis-GC/MS system was applied to extract the pesticides from water samples over a concentration range of 10-3 to 103 μg*l-1.The method showed good li-nearity for the tested concentration range with regression coefficients of 0.995 for over 5 decades.Limits of detection at a sub-ng*l-1(ppt)level were achieved and the reproducibility of the measurements was found to be fairly good,with relative standard deviation below 8%.
Finite-Element Analysis of Forced Convection and Conduction
Wieting, A. R.
1982-01-01
TAP2 thermal-analysis program was developed as part of research on finite element methodology for thermal analysis of convectively cooled structures, such as scramjet engines and hypersonic aircraft. Program simplifies computations when both structural and thermal analyses are required and is suited for thermal analysis of nuclear reactors and solar-panel heating systems.
无
2008-01-01
A numerical model is developed in this paper to calculate the bending moments of flexural members through integration in 3D solid finite element analyses according to the nonlinear constitutive model of concrete and the elastoplastic constitutive model of steel,utilizing the stress condition of the cross-section,considering the destruction characteristic of reinforced concrete members,and based on the plane cross-section assumption.The results of this model give good agreement with those of the classical me...
Axisymmetric solid-of-revolution finite elements with rotational degrees of freedom
Long, CS
2009-01-01
Full Text Available , based on a Hellinger–Reissner like formulation, possesses an additional assumed stress field. Furthermore, an element correction, often employed in membrane elements with drilling degrees of freedom to alleviate membrane-bending locking, is adapted...
3D Rigid-Plastic Finite Element Analysis for Skew Rolling Process of the Stepped Part
Gang FANG; Pan ZENG
2003-01-01
Based on rigid-plastic finite element method, a skew rolling process of stepped part is simulated. Considering nodesaving and effective remeshing, the tetrahedron solid elements are used to discrete workpiece. The workpiece material adopts rigid-plastic m
Finite element analysis of posterior cervical fixation.
Duan, Y; Wang, H H; Jin, A M; Zhang, L; Min, S X; Liu, C L; Qiu, S J; Shu, X Q
2015-02-01
Despite largely, used in the past, biomechanical test, to investigate the fixation techniques of subaxial cervical spine, information is lacking about the internal structural response to external loading. It is not yet clear which technique represents the best choice and whether stabilization devices can be efficient and beneficial for three-column injuries (TCI). The different posterior cervical fixation techniques (pedicle screw PS, lateral mass screw LS, and transarticular screw TS) have respective indications. A detailed, geometrically accurate, nonlinear C3-C7 finite element model (FEM) had been successfully developed and validated. Then three FEMs were reconstructed from different fixation techniques after C4-C6 TCI. A compressive preload of 74N combined with a pure moment of 1.8 Nm in flexion, extension, left-right lateral bending, and left-right axial rotation was applied to the FEMs. The ROM results showed that there were obvious significant differences when comparing the different fixation techniques. PS and TS techniques can provide better immediate stabilization, compared to LS technique. The stress results showed that the variability of von Mises stress in the TS fixation device was minimum and LS fixation device was maximum. Furthermore, the screws inserted by TS technique had high stress concentration at the middle part of the screws. Screw inserted by PS and LS techniques had higher stress concentration at the actual cap-rod-screw interface. The research considers that spinal surgeon should first consider using the TS technique to treat cervical TCI. If PS technique is used, we should eventually prolong the need for external bracing in order to reduce the higher risk of fracture on fixation devices. If LS technique is used, we should add anterior cervical operation for acquire a better immediate stabilization. Copyright © 2014 Elsevier Masson SAS. All rights reserved.
ELASTO-PLASTIC FINITE ELEMENT ANALYSIS OF HOOK'S JOINT
Adnan ATICI
1996-03-01
Full Text Available In this study, stress analysis has been done in Hooke's joint by the finite element method. In finite element meshing, isoparametric quadrilateral elements with four nodes has been chosen and Lagrange polynomial has been used as the interpolation function. The special computer program has been written for the automatic mesh generation. In addition the other program has been developed to solve the finite element problems. Elastoplastic stress analysis is done to calculate the residual stresses in hooke's joint. Elasto-plastic stress values are calculated under loading from 400 daN to 1000 daN with increment of 100 daN. In this analysis "The initial stress method" is used.
Analysis of trace elements in opal using PIXE
Hinrichs, Ruth, E-mail: ruth.hinrichs@ufrgs.br [Instituto de Geociências, Universidade Federal do Rio Grande do Sul, Porto Alegre, RS (Brazil); Programa de Pós-graduação em Física, UFRGS, Porto Alegre, RS (Brazil); Bertol, A.P.L. [Programa de Pós-graduação em Física, UFRGS, Porto Alegre, RS (Brazil); Vasconcellos, M.A.Z. [Programa de Pós-graduação em Física, UFRGS, Porto Alegre, RS (Brazil); Instituto de Física, UFRGS, Porto Alegre, RS (Brazil)
2015-11-15
Particle induced X-ray emission (PIXE) analysis is particularly important for the analysis of trace elements of precious samples, being one of the few methods to determine elements with ppm concentration that does not affect sample integrity. A PIXE methodology for trace element analysis in opal was developed. To avoid detector count saturation due to the high number of Si-Kα X-rays generated in the sample, several filters were employed to optimize the reduction of the Si-Kα signal, while maintaining acceptable intensities of the other relevant X-ray lines. Two proton beam energies were tested, to establish the signal to noise ratio in different X-ray energies. Spectra were fitted with the software GUPIX, using a matrix composition determined with electron beam excited energy dispersive X-ray spectrometry. Above the energy of the silicon X-ray, several trace elements were quantified.
Some Elements of Operational Modal Analysis
Rune Brincker
2014-01-01
This paper gives an overview of the main components of operational modal analysis (OMA) and can serve as a tutorial for research oriented OMA applications. The paper gives a short introduction to the modeling of random responses and to the transforms often used in OMA such as the Fourier series, the Fourier integral, the Laplace transform, and the Z-transform. Then the paper introduces the spectral density matrix of the random responses and presents the theoretical solutions for correlation f...
Study of Suspended Solid in Constructed Wetland Using Rare Earth Elements
Xiao, Z. X. Z.
2015-12-01
Constructed wetland (CW) is one of the commonly used technologies in wastewater treatment. By means of the biochemical interactions among water, microscopic organism, aquatic plant and sediments in natural environment CW can remove biochemical oxygen demand (BOD), ammoniacal nitrogen, suspended solid (SS) and heavy metals. In this study, rare earth elements (REEs) were used as a natural tracer for the study of SS in the CW. The studied CW, Hebao Island free water surface CW, is located in Chiayi County, south Taiwan. The CW is designed for removing SS and BOD due to the pollution from livestock farms in the upstream area. However, the removal of SS was not effective. In some cases, the SS concentration of inflow is even higher than that of outflow. That the sediments on the slope were flushed into the CW was considered as the main problem. After all the refinement, the issue has not improved yet. In the study, the water samples were filtered with 1.0μm filter paper. Then, part of water samples were digested by ultrapure nitric acid to obtain the water representing the total of dissolved and suspended matters. The others were filtered by 0.1μm filter, which represent the matters in dissolved form. REEs and most of metals were subsequently measured with ICP-MS. REEs generally have a unique source and would fractionate in certain regular patterns during biochemical reactions due to lanthanide contraction. They can be an excellent natural tracer in the environmental researches. After normalized by North American Shale Composite, the REEs pattern for the samples with the total of dissolved and suspended matters is characterized by a middle REE (MREE) enrichment and light REE (LREE) depletion. According to the previous theoretical studies, the MREE enrichment could be achieved by a selected adsorption of MREEs by organic matters, which is generally humic substance in natural surface water. It is suggested that the refinement of removal efficiency of SS should focus on
ANALYSIS OF DESIGN ELEMENTS IN SKI SUITS
Birsen Çileroğlu
2014-06-01
Full Text Available Popularity of Ski Sport in 19th century necessitated a new perspective on protective skiing clothing ag ainst the mountain climates and excessive cold. Winter clothing were the basis of ski attire during this period. By the beginning of 20th century lining cloth were used to minimize the wind effect. The difference between the men and women’s ski attire of the time consisted of a knee - length skirts worn over the golf trousers. Subsequent to the First World War, skiing suit models were influenced by the period uniforms and the producers reflected the fashion trends to the ski clothing. In conformance with th e prevailing trends, ski trousers were designed and produced for the women thus leading to reduction in gender differences. Increases in the ski tourism and holding of the first winter olympics in 1924 resulted in variations in ski attires, development of design characteristics, growth in user numbers, and enlargement of production capacities. Designers emphasized in their collections combined presence of elegance and practicality in the skiing attire. In 1930s, the ski suits influenced by pilots’ uniforms included characteristics permitting freedom of motion, and the design elements exhibited changes in terms of style, material and aerodynamics. In time, the ski attires showed varying design features distinguishing professionals from the amateurs. While protective functionality was primary consideration for the amateurs, for professionals the aerodynamic design was also a leading factor. Eventually, the increased differences in design characteristics were exhibited in ski suit collections, World reknown brands were formed, production and sales volumes showed significant rise. During 20th century the ski suits influenced by fashion trends to acquire unique styles reached a position of dominance to impact current fashion trends, and apart from sports attir es they became a style determinant in the clothing of cold climates. Ski suits
Quantitative elemental analysis of major, minor and trace elements in coal and host rocks by logging
Stephen Fraser; Craig Smith [CSIRO Exploration & Mining (Australia)
2008-12-15
Knowledge of the distribution of major, minor and trace elements in coals and interburden materials is increasingly important. Technological developments now suggest that such elemental distributions may be determined using a downhole logging tool. This study was undertaken to achieve two goals. The first was to survey the industry to determine those elements of interest to the coal industry and their associated detection limits. The second was to use this information as one of the inputs to select the best technique for determining elemental abundances using a downhole logging tool in both production and exploration environments. A questionnaire was circulated widely and received a total of 15 responses. From these responses elements of interest were tabulated for reference to the Australian Coal Industry. Three technologies were evaluated as having potential to be incorporated into a downhole environment: X-Ray Fluorescence (XRF), Laser Induced Breakdown Spectroscopy (LIBS), and Prompt Gamma Neutron Activation Analysis (PGNAA) using a neutron generator. Various criteria were used to evaluate these techniques including operator and environmental safety, ease of implementation and operation, and performance with respect to the detection of the elements of interest to the coal industry. After due consideration, we recommend that the most practical way forward is the neutron activation (PGNAA and DGNAA) method using a neutron generator as the neutron source.
Use of X-ray Fluorescence Analysis for the Determination of Rare Earth Elements
Schramm, Rainer
2016-09-01
X-ray fluorescence spectrometry (XRF) is a powerful tool for the analysis of solid material. That is the reason why the technique was applied for the determination of rare earth elements (REEs) since about 1970. At present, energy-dispersive XRF and wavelength-dispersive XRF are used for the analysis of pressed powder pellets or fused Li-borate beads containing REEs. The production of reliable results can only be achieved by careful optimization of the parameter, in particular the selection of spectral lines. The quantification is based on a calibration realized by using reference samples.
Laser-induced breakdown spectroscopy for real time and online elemental analysis
Rai, V N; Yueh, Fang-Yu; Singh, J P
2014-01-01
Laser-induced breakdown spectroscopy (LIBS) is a laser based diagnostics used to study atomic emission from the expanding plasma plume formed during the laser-matter interaction. It provides valuable information about the composition of the target material. LIBS has proved its potential application in the analysis of impurities, pollutants and toxic elements in various types of matrices of different samples (solid, liquid and gases), even those present under difficult and harsh environmental conditions. This article reviews some recent developments in the field, and its wide application in various fields of research and analysis.
Analysis of solid-liquid phase change heat transfer enhancement
张寅平; 王馨
2002-01-01
Solid-liquid phase change processes have two important features: the process is an approximately isothermal process and the heat of fusion of phase change material tends to be much greater than its specific heat. Therefore, if any phase change material adjacent to a hot or cold surface undergoes phase change, the heat transfer rate on the surface will be noticeably enhanced. This paper presents a novel insight into the mechanisms of heat transfer enhancement induced by solid-liquid phase change based on the analogy analysis for heat conduction with an internal heat source and solid-liquid phase change heat transfer. Three degrees of surface heat transfer enhancement for different conditions are explored, and corresponding formulae are written to describe them. The factors influencing the degrees of heat transfer enhancement are clarified and their effects quantitatively analyzed. Both the novel insight and the analysis contribute to effective application of phase change heat transfer enhancement technique.
Woo-Young Jung
2015-04-01
Full Text Available For the solution of geometrically nonlinear analysis of plates and shells, the formulation of a nonlinear nine-node refined first-order shear deformable element-based Lagrangian shell element is presented. Natural co-ordinate-based higher order transverse shear strains are used in present shell element. Using the assumed natural strain method with proper interpolation functions, the present shell element generates neither membrane nor shear locking behavior even when full integration is used in the formulation. Furthermore, a refined first-order shear deformation theory for thin and thick shells, which results in parabolic through-thickness distribution of the transverse shear strains from the formulation based on the third-order shear deformation theory, is proposed. This formulation eliminates the need for shear correction factors in the first-order theory. To avoid difficulties resulting from large increments of the rotations, a scheme of attached reference system is used for the expression of rotations of shell normal. Numerical examples demonstrate that the present element behaves reasonably satisfactorily either for the linear or for geometrically nonlinear analysis of thin and thick plates and shells with large displacement but small strain. Especially, the nonlinear results of slit annular plates with various loads provided the benchmark to test the accuracy of related numerical solutions.
Finite element analysis of an inflatable torus considering air mass structural element
Gajbhiye, S. C.; Upadhyay, S. H.; Harsha, S. P.
2014-01-01
Inflatable structures, also known as gossamer structures, are at high boom in the current space technology due to their low mass and compact size comparing to the traditional spacecraft designing. Internal pressure becomes the major source of strength and rigidity, essentially stiffen the structure. However, inflatable space based membrane structure are at high risk to the vibration disturbance due to their low structural stiffness and material damping. Hence, the vibration modes of the structure should be known to a high degree of accuracy in order to provide better control authority. In the past, most of the studies conducted on the vibration analysis of gossamer structures used inaccurate or approximate theories in modeling the internal pressure. The toroidal shaped structure is one of the important key element in space application, helps to support the reflector in space application. This paper discusses the finite-element analysis of an inflated torus. The eigen-frequencies are obtained via three-dimensional small-strain elasticity theory, based on extremum energy principle. The two finite-element model (model-1 and model-2) have cases have been generated using a commercial finite-element package. The structure model-1 with shell element and model-2 with the combination of the mass of enclosed fluid (air) added to the shell elements have been taken for the study. The model-1 is computed with present analytical approach to understand the convergence rate and the accuracy. The convergence study is made available for the symmetric modes and anti-symmetric modes about the centroidal-axis plane, meeting the eigen-frequencies of an inflatable torus with the circular cross section. The structural model-2 is introduced with air mass element and analyzed its eigen-frequency with different aspect ratio and mode shape response using in-plane and out-plane loading condition are studied.
Tolerance analysis and variational solid geometry
Watterberg, P. [Sandia National Labs., Albuquerque, NM (United States). Intelligent Systems and Robotics Center
1998-01-01
The fields of tolerancing and assembly analysis have depended for decades on ad hoc, shop floor methods. This causes serious problems when subjected toleranced designs to automated, analytical methods. This project attempted to further the formalization and mathematization of tolerancing by extending the concept of the Maximum Material Part. A software system was envisioned that would guide designers in the use of appropriate tolerance specifications and then create software models of Maximum Material Parts from the toleranced nominal parts.
Stone, C.M.
1997-07-01
SANTOS is a finite element program designed to compute the quasistatic, large deformation, inelastic response of two-dimensional planar or axisymmetric solids. The code is derived from the transient dynamic code PRONTO 2D. The solution strategy used to compute the equilibrium states is based on a self-adaptive dynamic relaxation solution scheme, which is based on explicit central difference pseudo-time integration and artificial mass proportional damping. The element used in SANTOS is a uniform strain 4-node quadrilateral element with an hourglass control scheme to control the spurious deformation modes. Finite strain constitutive models for many common engineering materials are included. A robust master-slave contact algorithm for modeling sliding contact is implemented. An interface for coupling to an external code is also provided. 43 refs., 22 figs.
Laursen, Tod A
2003-01-01
This book comprehensively treats the formulation and finite element approximation of contact and impact problems in nonlinear mechanics. Intended for students, researchers and practitioners interested in numerical solid and structural analysis, as well as for engineers and scientists dealing with technologies in which tribological response must be characterized, the book includes an introductory but detailed overview of nonlinear finite element formulations before dealing with contact and impact specifically. Topics encompassed include the continuum mechanics, mathematical structure, variational framework, and finite element implementations associated with contact/impact interaction. Additionally, important and currently emerging research topics in computational contact mechanics are introduced, encompassing such topics as tribological complexity, conservative treatment of inelastic impact interaction, and novel spatial discretization strategies.
Preliminary Analysis of a Fully Solid State Magnetocaloric Refrigeration
Abdelaziz, Omar [ORNL
2016-01-01
Magnetocaloric refrigeration is an alternative refrigeration technology with significant potential energy savings compared to conventional vapor compression refrigeration technology. Most of the reported active magnetic regenerator (AMR) systems that operate based on the magnetocaloric effect use heat transfer fluid to exchange heat, which results in complicated mechanical subsystems and components such as rotating valves and hydraulic pumps. In this paper, we propose an alternative mechanism for heat transfer between the AMR and the heat source/sink. High-conductivity moving rods/sheets (e.g. copper, brass, iron, graphite, aluminum or composite structures from these) are utilized instead of heat transfer fluid significantly enhancing the heat transfer rate hence cooling/heating capacity. A one-dimensional model is developed to study the solid state AMR. In this model, the heat exchange between the solid-solid interfaces is modeled via a contact conductance, which depends on the interface apparent pressure, material hardness, thermal conductivity, surface roughness, surface slope between the interfaces, and material filled in the gap between the interfaces. Due to the tremendous impact of the heat exchange on the AMR cycle performance, a sensitivity analysis is conducted employing a response surface method, in which the apparent pressure, effective surface roughness and grease thermal conductivity are the uncertainty factors. COP and refrigeration capacity are presented as the response in the sensitivity analysis to reveal the important factors influencing the fully solid state AMR and optimize the solid state AMR efficiency. The performances of fully solid state AMR and traditional AMR are also compared and discussed in present work. The results of this study will provide general guidelines for designing high performance solid state AMR systems.
Piezoelectric Analysis of Saw Sensor Using Finite Element Method
Vladimír KUTIŠ; Gabriel GÁLIK; Ivan RÝGER; Murín, Justín; Juraj HRABOVSKÝ; Juraj PAULECH; Tibor LALINSKÝ
2013-01-01
In this contribution modeling and simulation of surface acoustic waves (SAW) sensor using finite element method will be presented. SAW sensor is made from piezoelectric GaN layer and SiC substrate. Two different analysis types are investigated - modal and transient. Both analyses are only 2D. The goal of modal analysis, is to determine the eigenfrequency of SAW, which is used in following transient analysis. In transient analysis, wave propagation in SAW sensor is investigated. Both analyses ...
Some Elements of Operational Modal Analysis
Rune Brincker
2014-01-01
Full Text Available This paper gives an overview of the main components of operational modal analysis (OMA and can serve as a tutorial for research oriented OMA applications. The paper gives a short introduction to the modeling of random responses and to the transforms often used in OMA such as the Fourier series, the Fourier integral, the Laplace transform, and the Z-transform. Then the paper introduces the spectral density matrix of the random responses and presents the theoretical solutions for correlation function and spectral density matrix under white noise loading. Some important guidelines for testing are mentioned and the most common techniques for signal processing of the operating signals are presented. The algorithms of some of the commonly used time domain and frequency domain identification techniques are presented and finally some issues are discussed such as mode shape scaling, and mode shape expansion. The different techniques are illustrated on the difficult case of identifying the three first closely spaced modes of the Heritage Court Tower building.
Perspectives on clinical possibility: elements of analysis.
Chiffi, Daniele; Zanotti, Renzo
2016-08-01
Possibility is one of the most common modalities in reasoning and argumentation. Various kinds of modal concepts have been identified in philosophical and logical discussion of the metaphysics of modality. We focus here on the concept of clinical possibility. A critical analysis of what is intended as clinical possibility has not yet received sufficient examination, although the concept is extensively used in clinical reasoning. We present arguments to emphasize some desirable features associated with the concept of clinical possibility. We argue that almost all clinical possibilities are potentialities, that is, possibilities that may be actualized by effective, appropriate and feasible interventions. However, in some limited cases, even mere possibilities - which may or may not be actualized, since we do not have the required knowledge - may be involved in clinical reasoning, and we present some examples in this paper. We then introduce some basic views on the nature of possibility showing their validity and limitations when applied to the concept of clinical possibility. Lastly, we conjecture that clinical possibility is a normative modality that can be formalized in a multimodal system with epistemic and deontic logical operators.
Finite element analysis of piezoelectric underwater transducers for acoustic characteristics
Kim, Jae Hwan [Inha University, Incheon (Korea, Republic of); Kim, Heung Soo [Catholic University, Daegu (Korea, Republic of)
2009-02-15
This paper presents a simulation technique for analyzing acoustic characteristics of piezoelectric underwater transducers. A finite element method is adopted for modeling piezoelectric coupled problems including material damping and fluid-structure interaction problems by taking system matrices in complex form. For the finite element modeling of unbounded acoustic fluid, infinite wave envelope element (IWEE) is adopted to take into account the infinite domain. An in-house finite element program is developed and technical issues for implementing the program are explained. Using the simulation program, acoustic characteristics of tonpilz transducer are analyzed in terms of modal analysis, radiated pressure distribution, pressure spectrum, transmitting-voltage response and impedance analysis along with experimental comparison. The developed simulation technique can be used for designing ultrasonic transducers in the areas of nondestructive evaluation, underwater acoustics and bioengineering
Finite element analysis for acoustic characteristics of a magnetostrictive transducer
Kim, Jaehwan; Jung, Eunmi
2005-12-01
This paper presents a finite element analysis for a magnetostrictive transducer by taking into account the nonlinear behavior of the magnetostrictive material and fluid interaction. A finite element formulation is derived for the coupling of magnetostrictive and elastic materials based upon a separated magnetic and displacement field calculation and a curve fitting technique of material properties. The fluid and structure coupled problem is taken into account based upon pressure and velocity potential fields formulation. Infinite wave envelope elements are introduced at an artificial boundary to deal with the infinite fluid domain. A finite element code for the analysis of a magnetostrictive transducer is developed. A magnetostrictive tonpilz transducer is taken as an example and verification for the developed program is made by comparing with a commercial code. The acoustic characteristics of the magnetostrictive tonpilz transducer are calculated in terms of radiation pattern and transmitted current response.
Elemental imaging of rat epididymis by micro-PIXE analysis
Homma-Takeda, S.; Nishimura, Y.; Watanabe, Y.; Imaseki, H.; Yukawa, M.
2003-09-01
The epididymis, a male reproductive organ, which is a highly convoluted duct, plays an important role in transportation of spermatozoa, their maturation, and their storage. Although major elements, such as P, S and K, as well as trace elements, such as Mn, Cu, Zn, Se, are known to be essential for spermatogenesis, detailed distributions of the elements in the epididymis are only poorly understood. In the present study, Mn, Cu, Zn and Se levels in the epididymis were examined in male Wistar rats by inductively coupled argon plasma-mass spectrometry (ICP-MS) analysis and in situ multi-elemental distributions of epididymal sections were determined by micro-PIXE (particle induced X-ray emission) analysis. The Zn, Cu and Se concentrations in the epididymis of the young adult rats were around 30 μg/g wet weight, 2 μg/g wet weight and 1 μg/g wet weight, respectively, and their Mn were less than 0.5 μg/g wet weight. PIXE imaging of P and K exhibited that P and K were higher in the epididymal epithelium. In contrast, more S was detected in the lumen, which is composed of spermatozoa and a fluid. Elemental imagings of the trace elements were unclear compared with the major elements, but information about zinc localization in the epididymis was obtained.
Elemental imaging of rat epididymis by micro-PIXE analysis
Homma-Takeda, S.; Nishimura, Y. E-mail: y_nishim@nirs.go.jp; Watanabe, Y.; Imaseki, H.; Yukawa, M
2003-09-01
The epididymis, a male reproductive organ, which is a highly convoluted duct, plays an important role in transportation of spermatozoa, their maturation, and their storage. Although major elements, such as P, S and K, as well as trace elements, such as Mn, Cu, Zn, Se, are known to be essential for spermatogenesis, detailed distributions of the elements in the epididymis are only poorly understood. In the present study, Mn, Cu, Zn and Se levels in the epididymis were examined in male Wistar rats by inductively coupled argon plasma-mass spectrometry (ICP-MS) analysis and in situ multi-elemental distributions of epididymal sections were determined by micro-PIXE (particle induced X-ray emission) analysis. The Zn, Cu and Se concentrations in the epididymis of the young adult rats were around 30 {mu}g/g wet weight, 2 {mu}g/g wet weight and 1 {mu}g/g wet weight, respectively, and their Mn were less than 0.5 {mu}g/g wet weight. PIXE imaging of P and K exhibited that P and K were higher in the epididymal epithelium. In contrast, more S was detected in the lumen, which is composed of spermatozoa and a fluid. Elemental imagings of the trace elements were unclear compared with the major elements, but information about zinc localization in the epididymis was obtained.
Comparative analysis of solid waste management in 20 cities
Wilson, D.C.; Rodic-Wiersma, L.; Scheinberg, A.; Velis, C.A.; Alabaster, G.
2012-01-01
This paper uses the ‘lens’ of integrated and sustainable waste management (ISWM) to analyse the new data set compiled on 20 cities in six continents for the UN-Habitat flagship publication Solid Waste Management in the World’s Cities. The comparative analysis looks first at waste generation rates
Solid-phase microextraction for the analysis of biological samples
Theodoridis, G; Koster, EHM; de Jong, GJ
2000-01-01
Solid-phase microextraction (SPME) has been introduced for the extraction of organic compounds from environmental samples. This relatively new extraction technique has now also gained a lot of interest in a broad field of analysis including food, biological and pharmaceutical samples. SPME has a num
Hydrothermal analysis in engineering using control volume finite element method
Sheikholeslami, Mohsen
2015-01-01
Control volume finite element methods (CVFEM) bridge the gap between finite difference and finite element methods, using the advantages of both methods for simulation of multi-physics problems in complex geometries. In Hydrothermal Analysis in Engineering Using Control Volume Finite Element Method, CVFEM is covered in detail and applied to key areas of thermal engineering. Examples, exercises, and extensive references are used to show the use of the technique to model key engineering problems such as heat transfer in nanofluids (to enhance performance and compactness of energy systems),
THE SUPERCONVERGENCE ANALYSIS OF AN ANISOTROPIC FINITE ELEMENT
SHI Dongyang; ZHU Huiqing
2005-01-01
This paper deals with the high accuracy analysis of bilinear finite element on the class of anisotropic rectangular meshes. The inverse inequalities on anisotropic meshes are established. The superclose and the superconvergence are obtained for the second order elliptic problem. A numerical test is given, which coincides with our theoretical analysis.
Hands on applied finite element analysis application with ANSYS
Arslan, Mehmet Ali
2015-01-01
Hands on Applied Finite Element Analysis Application with Ansys is truly an extraordinary book that offers practical ways of tackling FEA problems in machine design and analysis. In this book, 35 good selection of example problems have been presented, offering students the opportunity to apply their knowledge to real engineering FEA problem solutions by guiding them with real life hands on experience.
Anisotropic rectangular nonconforming finite element analysis for Sobolev equations
SHI Dong-yang; WANG Hai-hong; GUO Cheng
2008-01-01
An anisotropic rectangular nonconforming finite element method for solving the Sobolev equations is discussed under semi-discrete and full discrete schemes.The corresponding optimal convergence error estimates and superclose property are derived,which are the same as the traditional conforming finite elements.Furthermore,the global superconvergence is obtained using a post-processing technique.The numerical results show the validity of the theoretical analysis.
Finite Element Analysis of MEMS Devices
Corrigan, Jennifer
2004-01-01
A side-slide actuator and a corrugated diaphragm actuator will be analyzed and optimized this summer. Coupled electrostatic and fluid analyses will also be initiated. Both the side-slide actuator and the corrugated diaphragm actuator will be used to regulate the flow of fuel in a jet engine. Many of the side-slide actuators will be placed on top of a fuel injector that is still in the developmental stage as well. The corrugated diaphragm actuator will also be used to regulate the flow of fuel in fuel injectors. A comparative analysis of the performance matrix of both actuators will be conducted. The side-slide actuator uses the concept of mechanical advantage to regulate the flow of fuel using electrostatic forces. It is made from Nickel, Silicon Carbide, and thin layers of Oxide. The slider will have a hole in the middle that will allow fuel to pass through the hole underneath it. The goal is to regulate the flow of fuel through the inlet. This means that the actuator needs to be designed so that when a voltage is applied to the push rod, the slider will deflect in the x-direction and be able to completely block the inlet and no fuel can pass through. Different voltage levels will be tested. The parameters that are being optimized are the thickness of the diaphragm, what kind of corrugation the diaphragm should have, the length, width, and thickness of the push rod, and what design should be used to return the slider. The current possibilities for a return rod are a built in spring on the slider, a return rod that acts like a spring, or a return rod that is identical to the push rod. The final actuator design should have a push rod that has rotational motion and no translation motion, a push rod thickness that prevents warping due to the slider, and a large ratio of the displacement on the bottom of the push rod to displacement on the top of the push rod. The corrugated diaphragm actuator was optimized last winter and this summer will be spent completing the
Qingdong Zeng
2015-10-01
Full Text Available Fluid-solid coupling is ubiquitous in the process of fluid flow underground and has a significant influence on the development of oil and gas reservoirs. To investigate these phenomena, the coupled mathematical model of solid deformation and fluid flow in fractured porous media is established. In this study, the discrete fracture model (DFM is applied to capture fluid flow in the fractured porous media, which represents fractures explicitly and avoids calculating shape factor for cross flow. In addition, the extended finite element method (XFEM is applied to capture solid deformation due to the discontinuity caused by fractures. More importantly, this model captures the change of fractures aperture during the simulation, and then adjusts fluid flow in the fractures. The final linear equation set is derived and solved for a 2D plane strain problem. Results show that the combination of discrete fracture model and extended finite element method is suited for simulating coupled deformation and fluid flow in fractured porous media.
Assessment of occupational safety risks in Floridian solid waste systems using Bayesian analysis.
Bastani, Mehrad; Celik, Nurcin
2015-10-01
Safety risks embedded within solid waste management systems continue to be a significant issue and are prevalent at every step in the solid waste management process. To recognise and address these occupational hazards, it is necessary to discover the potential safety concerns that cause them, as well as their direct and/or indirect impacts on the different types of solid waste workers. In this research, our goal is to statistically assess occupational safety risks to solid waste workers in the state of Florida. Here, we first review the related standard industrial codes to major solid waste management methods including recycling, incineration, landfilling, and composting. Then, a quantitative assessment of major risks is conducted based on the data collected using a Bayesian data analysis and predictive methods. The risks estimated in this study for the period of 2005-2012 are then compared with historical statistics (1993-1997) from previous assessment studies. The results have shown that the injury rates among refuse collectors in both musculoskeletal and dermal injuries have decreased from 88 and 15 to 16 and three injuries per 1000 workers, respectively. However, a contrasting trend is observed for the injury rates among recycling workers, for whom musculoskeletal and dermal injuries have increased from 13 and four injuries to 14 and six injuries per 1000 workers, respectively. Lastly, a linear regression model has been proposed to identify major elements of the high number of musculoskeletal and dermal injuries.
Probabilistic finite elements for transient analysis in nonlinear continua
Liu, W. K.; Belytschko, T.; Mani, A.
1985-01-01
The probabilistic finite element method (PFEM), which is a combination of finite element methods and second-moment analysis, is formulated for linear and nonlinear continua with inhomogeneous random fields. Analogous to the discretization of the displacement field in finite element methods, the random field is also discretized. The formulation is simplified by transforming the correlated variables to a set of uncorrelated variables through an eigenvalue orthogonalization. Furthermore, it is shown that a reduced set of the uncorrelated variables is sufficient for the second-moment analysis. Based on the linear formulation of the PFEM, the method is then extended to transient analysis in nonlinear continua. The accuracy and efficiency of the method is demonstrated by application to a one-dimensional, elastic/plastic wave propagation problem. The moments calculated compare favorably with those obtained by Monte Carlo simulation. Also, the procedure is amenable to implementation in deterministic FEM based computer programs.
Elemental speciation analysis, from environmental to biochemical challenge
Jitaru, P.; Barbante, C.
2006-12-01
Information regarding the distribution of metallic/metalloid chemical species in biological compartments is required for understanding their biochemical impact on living organisms. To obtain such information implies the use of a dedicated measurement approach, namely speciation analysis. The current trend in (elemental) speciation analysis regards bioinorganic applications. New analytical methodologies are therefore necessary for identification, detection and characterization of metal(loids) complexed or incorporated into biomolecules. The established element-speciation approaches developed for the determination of low molecular mass metal(loid) species (e.g. organometallic compounds) in environmental, food, toxicological and health sciences are presently being adapted for the determination of high molecular mass metal-species, generally related to biological processes. This is one of the newest approaches in terms of element speciation and is called metallomics; this concept refers to the totality of metal species in a cell and covers the inorganic element content and the ensemble of its complexes with biomolecules, particularly proteins, participating in the organisms' response to beneficial or harmful conditions. Compared to conventional elemental speciation analysis, the approach applied to bioinorganic analysis is challenging, particularly given the difficulties in identification/characterization of the organic (e.g. protein) content of such species. In addition, quantification is not feasible with the conventional approaches, which led to the exploitation of the unique feature of (post-column) online isotope dilution-mass spectrometry for species quantification in metallomics.
Ginzburg-Landau theory for the solid-liquid interface of bcc elements
Shih, W. H.; Wang, Z. Q.; Zeng, X. C.; Stroud, D.
1987-01-01
Consideration is given to a simple order-parameter theory for the interfacial tension of body-centered-cubic solids in which the principal order parameter is the amplitude of the density wave at the smallest nonzero reciprocal-lattice vector of the solid. The parameters included in the theory are fitted to the measured heat of fusion, melting temperature, and solid-liquid density difference, and to the liquid structure factor and its temperature derivative at freezing. Good agreement is found with experiment for Na and Fe and the calculated anisotropy of the surface tension among different crystal faces is of the order of 2 percent. On the basis of various assumptions about the universal behavior of bcc crystals at melting, the formalism predicts that the surface tension is proportional to the heat of fusion per surface atom.
Using Plate Finite Elements for Modeling Fillets in Design, Optimization, and Dynamic Analysis
Brown, A. M.; Seugling, R. M.
2003-01-01
A methodology has been developed that allows the use of plate elements instead of numerically inefficient solid elements for modeling structures with 90 degree fillets. The technique uses plate bridges with pseudo Young's modulus (Eb) and thickness (tb) values placed between the tangent points of the fillets. These parameters are obtained by solving two nonlinear simultaneous equations in terms of the independent variables rlt and twallt. These equations are generated by equating the rotation at the tangent point of a bridge system with that of a fillet, where both rotations are derived using beam theory. Accurate surface fits of the solutions are also presented to provide the user with closed-form equations for the parameters. The methodology was verified on the subcomponent level and with a representative filleted structure, where the technique yielded a plate model exhibiting a level of accuracy better than or equal to a high-fidelity solid model and with a 90-percent reduction in the number of DOFs. The application of this method for parametric design studies, optimization, and dynamic analysis should prove extremely beneficial for the finite element practitioner. Although the method does not attempt to produce accurate stresses in the filleted region, it can also be used to obtain stresses elsewhere in the structure for preliminary analysis. A future avenue of study is to extend the theory developed here to other fillet geometries, including fillet angles other than 90 and multifaceted intersections.
Vassilev, S.V. [Bulgarian Academy of Sciences, Sofia (Bulgaria). Institute of Applied Mineralogy
1994-03-01
The content, concentration trend and mode of occurrence of 40 trace elements in coal mixtures (coals and host rocks), fly ash, bottom ash and lagooned ash at four Bulgarian thermoelectric power stations (TPS) have been characterized. A complex of methods: separation, atomic emission and ICP spectroscopy, neutron activation, XRF, SEM, TEM, XRD, etc., was used. Trace elements in coal mixtures are concentrated mainly in the heavy fractions (above 2.9 g cm{sup -3}), authigenic minerals and organic matter; and to a lesser extent are present in the major detrital minerals and host rocks. A number of elements in the waste products, like coal mixtures (ash), exceed known Clarke contents. These are mostly the siderophilic, some lithophilic (Rb, Nb, Mo, Ba, REE, Hf) and chalcophilic (Cu, Zn, As) elements and U. The trace elements show different concentration trends in fly ash, but are more typical for non-magnetic, heavy and fine-grained fractions. They are commonly present as impurities in the glass phases, and are included in the structure of mineral phases. The accessory crystalline phases, element-organic compounds, liquid and gas forms, are of subordinate importance. Some elements, mostly from the chalcophilic (Cu, Zn, Ga, As, Sn, Sb) and lithophilic (Be, Y, Zr, Nb, Mo) groups, plus Co and U, show scattering trends into the atmosphere. For others, the combustion process appears to be a powerful factor causing relative increase in the fly ash. Considerable amounts of trace elments from stack emissions (Hf, As, Tl, Pb, etc.) have probably entered the soil near TPS. Trace elements can also occur in watersoluble forms (Li, Mo, Cs, halogen elements, V, As, Bi, etc.) in waste products and accumulate (Sr, Ba, Pb, etc.) in dump vegetation. 35 refs., 5 tabs.
Two-dimensional finite-element temperature variance analysis
Heuser, J. S.
1972-01-01
The finite element method is extended to thermal analysis by forming a variance analysis of temperature results so that the sensitivity of predicted temperatures to uncertainties in input variables is determined. The temperature fields within a finite number of elements are described in terms of the temperatures of vertices and the variational principle is used to minimize the integral equation describing thermal potential energy. A computer calculation yields the desired solution matrix of predicted temperatures and provides information about initial thermal parameters and their associated errors. Sample calculations show that all predicted temperatures are most effected by temperature values along fixed boundaries; more accurate specifications of these temperatures reduce errors in thermal calculations.
Grey interrelation analysis of alloy elements and steel corrosion
Zhang Jinglei; Hou Baorong; Huang Yanliang; Guo Gongyu [Chinese Academy of Sciences, Qingdao (China). Dept. of Oceanology
2000-07-01
Mathematical grey interrelation analysis method was used to study the correlation of alloy elements and low steel corrosion in the splash zone. Eighteen kinds of low alloy steels were selected for 350-day experiments in a large marine corrosion environment simulating apparatus. The analysis results showed that the correlation of alloy elements and alloy corrosion rate is in the order: Mn>Si>P>V>Cu>Al>Cr>Mo. The correlation degree was 0.92, 0.89, 0.86, 0.83, 0.82, 0.82, 0.81, 0.77. (orig.)
Orani, Anna Maria; Han, Eunmi; Mandjukov, Petko; Vassileva, Emilia
2015-01-01
Analytical procedure for the determination of As, Cd, Cu, Ni, Co and Cr in marine sediment samples using high-resolution continuum source graphite furnace atomic absorption spectrometry (HR CS AAS) and direct solid sample analysis has been developed. The application of fast programs in combination with direct solid sampling allows to eliminate the drying and pretreatment steps, however makes impossible the use of liquid standards for calibration. Iridium treated platforms were applied throughout the present study. Calibration technique based on the use of solid certified reference materials (marine sediments) similar to the nature of the analyzed sample and statistics of regression analysis were applied to the real sediment samples. The instrumental parameters were optimized in order to obtain reproducible and interference free analytical signals. The ISO-17025 requirements and Eurachem guidelines were followed in the validation of the proposed analytical procedure. Accordingly, blanks, selectivity, calibration, linearity, working range, trueness, repeatability reproducibility, limits of detection and quantification and expanded uncertainty (k = 2) for all investigated elements were assessed. Two different approaches for the estimation of measurement uncertainty were applied and obtained results compared. The major contributors to the combined uncertainty of the analyte mass fraction were found to be the homogeneity of the samples and the microbalance precision. The influence of sample particle sizes on the total combined uncertainty was also evaluated. Traceability to SI system of units of the obtained by the proposed analytical procedure results was demonstrated. Additionally, validation of the methodology developed was effectuated by the comparison of the obtained results with independent method e.g. ICP-MS with external calibration. The use of solid sampling HR CS AAS for the determination of trace elements in marine sediment matrix gives significant advantages
Dynamic characterization and analysis of space shuttle SRM solid propellant
Hufferd, W. L.
1979-01-01
The dynamic response properties of the space shuttle solid rocket moter (TP-H1148) propellant were characterized and the expected limits of propellant variability were established. Dynamic shear modulus tests conducted on six production batches of TP-H1148 at various static and dynamic strain levels over the temperature range from 40 F to 90 F. A heat conduction analysis and dynamic response analysis of the space shuttle solid rocket motor (SRM) were also conducted. The dynamic test results show significant dependence on static and dynamic strain levels and considerable batch-to-batch and within-batch variability. However, the results of the SRM dynamic response analyses clearly demonstrate that the stiffness of the propellant has no consequential on the overall SRM dynamic response. Only the mass of the propellant needs to be considered in the dynamic analysis of the space shuttle SRM.
Finite element analysis of rotating beams physics based interpolation
Ganguli, Ranjan
2017-01-01
This book addresses the solution of rotating beam free-vibration problems using the finite element method. It provides an introduction to the governing equation of a rotating beam, before outlining the solution procedures using Rayleigh-Ritz, Galerkin and finite element methods. The possibility of improving the convergence of finite element methods through a judicious selection of interpolation functions, which are closer to the problem physics, is also addressed. The book offers a valuable guide for students and researchers working on rotating beam problems – important engineering structures used in helicopter rotors, wind turbines, gas turbines, steam turbines and propellers – and their applications. It can also be used as a textbook for specialized graduate and professional courses on advanced applications of finite element analysis.
Highly Efficient Boundary Element Analysis of Whispering Gallery Microcavities
Pan, Leyuan
2014-01-01
We demonstrate that the efficiency of the boundary element whispering gallery microcavity analysis can be improved by orders of magnitude with the inclusion of Fresnel approximation. Using this formulation, simulation of a microdisk with wave-number-radius product as large as $kR\\approx8,000$ was demonstrated in contrast to a previous record of $kR\\approx100$. In addition to its high accuracy on computing the modal field distribution and resonance wavelength, this method yields a relative error of $10%$ in calculating the quality factor as high as $10^{11}$ through a direct root searching method where the conventional boundary element method failed to achieve. Finally, quadrupole shaped cavities and double disks as large as $100 {\\mu}m$ in diameter were modeled by employing as few as $512$ boundary elements whilst the simulation of such large cavities using conventional boundary element method were not reported previously.
Solid-state synthesis of monazite-type compounds containing tetravalent elements.
Bregiroux, Damien; Terra, Olivier; Audubert, Fabienne; Dacheux, Nicolas; Serin, Virgine; Podor, Renaud; Bernache-Assollant, Didier
2007-11-26
On the basis of optimized grinding/heating cycles developed for several phosphate-based ceramics, the preparation of brabantite and then monazite/brabantite solid solutions loaded with tetravalent thorium, uranium, and cerium (as a plutonium surrogate) was examined versus the heating temperature. The chemical reactions and transformations occurring when heating the initial mixtures of AnO2/CeO2, CaHPO(4).2H2O (or CaO), and NH4H2PO4 were identified through X-ray diffraction (XRD) and thermogravimetric/differential thermal analysis experiments. The incorporation of thorium, which presents only one stabilized oxidation state, occurs at 1100 degrees C. At this temperature, all the thorium-brabantite samples appear to be pure and single phase as suggested by XRD, electron probe microanalyses, and micro-Raman spectroscopy. By the same method, tetravalent uranium can be also stabilized in uranium-brabantite, i.e., Ca0.5U0.5PO4, after heating at 1200 degrees C. Both brabantites, Ca0.5Th0.5PO4 and Ca0.5U0.5PO4, begin to decompose when increasing the temperature to 1400 and 1300 degrees C, respectively, leading to a mixture of CaO and AnO2 by the volatilization of P4O10. In contrast to the cases of thorium and uranium, cerium(IV) is not stabilized during the heating treatment at high temperature. Indeed, the formation of Ca0.5Ce0.5PO4 appears impossible, due to the partial reduction of cerium(IV) into cerium(III) above 840 degrees C. Consequently, the systems always appear polyphase, with compositions of CeIII1-2xCeIVxCaxPO4 and Ca2P2O7. The same conclusion can be also given when discussing the incorporation of cerium(IV) into La1-2xCeIIIx-yCeIVyCay(PO4)1-x+y. This incomplete incorporation of cerium(IV) confirms the results obtained when trying to stabilize tetravalent plutonium in Ca0.5PuIV0.5PO4 samples.
Finite Element Analysis of 4-Cylinder Diesel Crankshaft
Jian Meng
2011-08-01
Full Text Available The stress analysis and modal analysis of a 4-cylinder crankshaft are discussed using finite element method in this paper. Three-dimension models of 480 diesel engine crankshaft and crankthrow were created using Pro/ENGINEER software The finite element analysis (FEM software ANSYS was used to analyse the vibration modal and the distortion and stress status of the crankthrow.The maximum deformation, maximum stress point and dangerous areas are found by the stress analysis of crankthrow. The relationship between the frequency and the vibration modal is explained by the modal analysis of crankshaft. The results would provide a valuable theoretical foundation for the optimization and improvement of engine design.
Thermal Analysis of Fission Moly Target Solid Waste Storage
Son, Hyung Min; Park, Jonghark [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of)
2016-10-15
There are various ways to produce Mo-99. Among them, nuclear transmutation of uranium target became the major one owing to its superior specific activity. After the fission molybdenum (FM) target is irradiated, it is transported to treatment facility to extract wanted isotope. During the process, various forms of wastes are produced including filter cake and other solid wastes. The filter cake is mostly consisted of decaying uranium compounds. The solid wastes are then packaged and moved to storage facility which will stay there for considerable amount of time. Being the continuous source of heat, the solid wastes are required to be cooled for the certain amount of time before transported to the storage area. In this study, temperature evaluation of the storage facility is carried out with pre-cooling time sensitivity to check its thermal integrity. In this study, thermal analysis on the FM target solid waste storage is performed. Finite volume method is utilized to numerically discretize and solve the geometry of interest. Analysis shows that the developed method can simulate temperature behavior during storage process, but needs to be checked against other code to see calculation accuracy. Highest temperature distribution is observed when every hole is filled with waste containers. Sensitivity results on pre-cooling time shows that at least 13 months of cooling is necessary to keep the structure integrity.
Solid waste integrated cost analysis model: 1991 project year report
1991-01-01
The purpose of the City of Houston's 1991 Solid Waste Integrated Cost Analysis Model (SWICAM) project was to continue the development of a computerized cost analysis model. This model is to provide solid waste managers with tool to evaluate the dollar cost of real or hypothetical solid waste management choices. Those choices have become complicated by the implementation of Subtitle D of the Resources Conservation and Recovery Act (RCRA) and the EPA's Integrated Approach to managing municipal solid waste;. that is, minimize generation, maximize recycling, reduce volume (incinerate), and then bury (landfill) only the remainder. Implementation of an integrated solid waste management system involving all or some of the options of recycling, waste to energy, composting, and landfilling is extremely complicated. Factors such as hauling distances, markets, and prices for recyclable, costs and benefits of transfer stations, and material recovery facilities must all be considered. A jurisdiction must determine the cost impacts of implementing a number of various possibilities for managing, handling, processing, and disposing of waste. SWICAM employs a single Lotus 123 spreadsheet to enable a jurisdiction to predict or assess the costs of its waste management system. It allows the user to select his own process flow for waste material and to manipulate the model to include as few or as many options as he or she chooses. The model will calculate the estimated cost for those choices selected. The user can then change the model to include or exclude waste stream components, until the mix of choices suits the user. Graphs can be produced as a visual communication aid in presenting the results of the cost analysis. SWICAM also allows future cost projections to be made.
Morris, J; Johnson, S
2007-12-03
The Distinct Element Method (also frequently referred to as the Discrete Element Method) (DEM) is a Lagrangian numerical technique where the computational domain consists of discrete solid elements which interact via compliant contacts. This can be contrasted with Finite Element Methods where the computational domain is assumed to represent a continuum (although many modern implementations of the FEM can accommodate some Distinct Element capabilities). Often the terms Discrete Element Method and Distinct Element Method are used interchangeably in the literature, although Cundall and Hart (1992) suggested that Discrete Element Methods should be a more inclusive term covering Distinct Element Methods, Displacement Discontinuity Analysis and Modal Methods. In this work, DEM specifically refers to the Distinct Element Method, where the discrete elements interact via compliant contacts, in contrast with Displacement Discontinuity Analysis where the contacts are rigid and all compliance is taken up by the adjacent intact material.
Finite element dynamic analysis on CDC STAR-100 computer
Noor, A. K.; Lambiotte, J. J., Jr.
1978-01-01
Computational algorithms are presented for the finite element dynamic analysis of structures on the CDC STAR-100 computer. The spatial behavior is described using higher-order finite elements. The temporal behavior is approximated by using either the central difference explicit scheme or Newmark's implicit scheme. In each case the analysis is broken up into a number of basic macro-operations. Discussion is focused on the organization of the computation and the mode of storage of different arrays to take advantage of the STAR pipeline capability. The potential of the proposed algorithms is discussed and CPU times are given for performing the different macro-operations for a shell modeled by higher order composite shallow shell elements having 80 degrees of freedom.
Analysis of illicit drugs by direct ablation of solid samples.
Bermúdez, Celina; Cabezas, Carlos; Mata, Santiago; Berdakin, Matias; Tejedor, Jesús M; Alonso, José L
2015-01-01
Analysis of illicit drugs arises as an important field of work given the high social impacts presented by drugs in the modern society. Direct laser ablation of solid compounds allows their analysis without sampling or preparation procedures. For that purpose, an experimental set-up that combines laser ablation with time-of- flight mass spectrometry has been constructed very recently to perform studies on the mass spectra of such drugs as 3,4-methylenedioxy-N-methylamphetamine, commonly known as MDMA or ecstasy. Analysis of the observed fragmentation pattern in mass spectra may elucidate the ablation-induced photofragmentation phenomena produced, which differ from those previously observed with conventional ionization methods.
Jacek Giersz; Krzysztof Jankowski; Monika Truskolaska
2015-01-01
A method for conducting fast and efficient gas chromatography based on short multicapillaries in straight alignment combined with atomic emission detection was developed for field analysis. The strategy enables for speciation analysis of organometallic compounds. The analytes are simultaneously ethylated and preconcentrated on a solid phase microextraction (SPME) fiber placed in the headspace over the sample for 25 min. The ethylated species are then completely separated and selectively quant...
Whirley, R.G.; Engelmann, B.E.
1993-11-01
This report is the User Manual for the 1993 version of DYNA3D, and also serves as a User Guide. DYNA3D is a nonlinear, explicit, finite element code for analyzing the transient dynamic response of three-dimensional solids and structures. The code is fully vectorized and is available on several computer platforms. DYNA3D includes solid, shell, beam, and truss elements to allow maximum flexibility in modeling physical problems. Many material models are available to represent a wide range of material behavior, including elasticity, plasticity, composites, thermal effects, and rate dependence. In addition, DYNA3D has a sophisticated contact interface capability, including frictional sliding and single surface contact. Rigid materials provide added modeling flexibility. A material model driver with interactive graphics display is incorporated into DYNA3D to permit accurate modeling of complex material response based on experimental data. Along with the DYNA3D Example Problem Manual, this document provides the information necessary to apply DYNA3D to solve a wide range of engineering analysis problems.
Handbook of the band structure of elemental solids from Z = 1 to Z = 112
Papaconstantopoulos, Dimitris A
2015-01-01
This handbook presents electronic structure data and tabulations of Slater-Koster parameters for the whole periodic table. This second edition presents data sets for all elements up to Z = 112, Copernicium, whereas the first edition contained only 53 elements. In this new edition, results are given for the equation of state of the elements together with the parameters of a Birch fit, so that the reader can regenerate the results and derive additional information, such as Pressure-Volume relations and variation of Bulk Modulus with Pressure. For each element, in addition to the equation of state, the energy bands, densities of states, and a set of tight-binding parameters is provided. For a majority of elements, the tight-binding parameters are presented for both a two- and three-center approximation. For the hcp structure, new three-center tight-binding results are given. Other new material in this edition include: energy bands and densities of states of all rare-earth metals, a discussion of the McMillan-Gas...
Standard laboratory hydraulic pressure drop characteristics of various solid and I&E fuel elements
Waters, E.D.; Horn, G.R.
1958-01-20
The purpose of this report is to present a set of standard pressure-drop curves for various fuel elements in process tubes of Hanford reactors. The flow and pressures within a process tube assembly under normal conditions are dependent to a large extent on the magnitude of the pressure drop across the fuel elements. The knowledge of this pressure drop is important in determination of existing thermal conditions within the process tubes and in predicting conditions for new fuel element designs or changes in operating conditions. The pressure-flow relations for the different Hanford fuel element-process tube assemblies have all been determined at one time or another in the 189-D Hydraulics Laboratory but the data had never been collected into a single report. Such a report is presented now in the interest of establishing a set of ``standard curves`` as determined by laboratory investigations. It must be recognized that the pressure drops of fuel elements in actual process tubes in the reactors may be slightly different than those reported here. The data presented here were obtained in new process tubes while reactor process tubes are usually either corroded or filmed, depending on their past history.
Trace elements in coloured opals using neutron activation analysis
McOrist, G.D.; Smallwood, A. [Australian Nuclear Science and Technology Organisation, Lucas Heights, NSW (Australia)
1996-12-31
Neutron activation analysis (NAA) is a technique particularly suited to analysing opals since it is non-destructive and the silica matrix of opals is not prone to significant activation. It was used to determine the concentration of trace elements in 50 samples of orange, yellow, green, blue and pink opals as well as 18 samples of colourless opals taken from a number of recognised fields in Australia, Peru, Mexico and USA. The results were then evaluated to determine if a relationship existed between trace element content and opal colour. The mean concentration of most of the elements found in orange, yellow and colourless opals were similar with few exceptions. This indicated that, for these samples, colour is not related to the trace elements present. However, the trace element profile of the green, pink and blue opals was found to be significantly different with each colour having a much higher concentration of certain trace elements when compared with all other opals analysed. 7 refs.
Limit Analysis of 3D Reinforced Concrete Beam Elements
Larsen, Kasper P.; Nielsen, Leif Otto; Poulsen, Peter Noe
2012-01-01
A new finite-element framework for lower-bound limit analysis of reinforced concrete beams, subjected to loading in three dimensions, is presented. The method circumvents the need for a direct formulation of a complex section-force-based yield criterion by creating a discrete representation of th...
Finite Element Vibration and Dynamic Response Analysis of Engineering Structures
Jaroslav Mackerle
2000-01-01
Full Text Available This bibliography lists references to papers, conference proceedings, and theses/dissertations dealing with finite element vibration and dynamic response analysis of engineering structures that were published from 1994 to 1998. It contains 539 citations. The following types of structures are included: basic structural systems; ground structures; ocean and coastal structures; mobile structures; and containment structures.
Finite element analysis of bone loss around failing implants
Wolff, J.; Narra, N.; Antalainen, A.K.; Valášek, J.; Kaiser, J.; Sandór, G.K.; Marcián, P.
2014-01-01
Dental implants induce diverse forces on their surrounding bone. However, when excessive unphysiological forces are applied, resorption of the neighbouring bone may occur. The aim of this study was to assess possible causes of bone loss around failing dental implants using finite element analysis. A
SUPERCONVERGENCE ANALYSIS OF A NONCONFORMING TRIANGULAR ELEMENT ON ANISOTROPIC MESHES
Dongyang SHI; Hui LIANG; Caixia WANG
2007-01-01
The class of anisotropic meshes we conceived abandons the regular assumption. Some distinct properties of Carey's element are used to deal with the superconvergence for a class of twodimensional second-order elliptic boundary value problems on anisotropic meshes. The optimal results are obtained and numerical examples are given to confirm our theoretical analysis.
Elements of Constitutive Modelling and Numerical Analysis of Frictional Soils
Jakobsen, Kim Parsberg
This thesis deals with elements of elasto-plastic constitutive modelling and numerical analysis of frictional soils. The thesis is based on a number of scientific papers and reports in which central characteristics of soil behaviour and applied numerical techniques are considered. The development...
A Thermal Analysis of High-Drive Ring Transducer Elements
2005-08-15
and Mass Transfer, Addison-Wesley, Reading MA, 1988. 12. G. Arfken , Mathematical Methods for Physicists, Academic Press, 1985. 13. "FLUX2D...Electromagnetic and Thermal Analysis 2-D Finite Element Program," Magsoft Corporation, Troy, NY. 14. G. B. Arfken , D. F. Griffing, D. C. Kelly, and J. Priest
Thermogravimetric analysis in the study of solid fuels
Wróblewski Robert
2016-01-01
Full Text Available Depletion of fossil energy is the reason for the exploration of the possibility of the use of renewable energy resources. In the article describes a method of thermo-gravimetric analysis and concept, design and execution of the instrument to thermogravimetric measurements placed in the Laboratory of Fuel and Energy Conversion of Institute of Electrical Power Engineering of Poznan University of Technology. The further part of the paper contains the results of the tests carried out on two types of solid fuels (pellets from sawdust and energy willow wood chips in the form of a thermogravimetric curves. This analysis is to determine the level of the pyrolysis process temperature and degree of conversion of solid fuels into fuel gas. These studies are conducted by looking at opportunities to improve the energy efficiency of the gasification process of biomass.
ON THE ANISOTROPIC ACCURACY ANALYSIS OF ACM'S NONCONFORMING FINITE ELEMENT
Dong-yang Shi; Shi-peng Mao; Shao-chun Chen
2005-01-01
The main aim of this paper is to study the superconvergence accuracy analysis of the famous ACM's nonconforming finite element for biharmonic equation under anisotropic meshes. By using some novel approaches and techniques, the optimal anisotropic interpolation error and consistency error estimates are obtained. The global error is of order O(h2). Lastly, some numerical tests are presented to verify the theoretical analysis.
Material nonlinear analysis via mixed-iterative finite element method
Sutjahjo, Edhi; Chamis, Christos C.
1992-01-01
The performance of elastic-plastic mixed-iterative analysis is examined through a set of convergence studies. Membrane and bending behaviors are tested using 4-node quadrilateral finite elements. The membrane result is excellent, which indicates the implementation of elastic-plastic mixed-iterative analysis is appropriate. On the other hand, further research to improve bending performance of the method seems to be warranted.
Piezoelectric Analysis of Saw Sensor Using Finite Element Method
Vladimír KUTIŠ
2013-06-01
Full Text Available In this contribution modeling and simulation of surface acoustic waves (SAW sensor using finite element method will be presented. SAW sensor is made from piezoelectric GaN layer and SiC substrate. Two different analysis types are investigated - modal and transient. Both analyses are only 2D. The goal of modal analysis, is to determine the eigenfrequency of SAW, which is used in following transient analysis. In transient analysis, wave propagation in SAW sensor is investigated. Both analyses were performed using FEM code ANSYS.
Solid-state synthesis of monazite-type compounds containing tetravalent elements
Bregiroux, D.; Audubert, F. [DEN/DEC/SPUA/LTEC, Commissariat Energie Atom, F-13108 St Paul Les Durance (France); Bregiroux, D. [CNRS, UMR 6638, Lab Sci Procedes Ceram and Traitements Surface, F-87060 Limoges (France); Terra, O.; Dacheux, N. [Univ Paris 11, Inst Phys Nucl, Grp Radiochim, F-91406 Orsay (France); Serin, V. [Ctr Elaborat Mat and Etud Struct, Grp Nanomat, F-31055 Toulouse (France); Podor, R. [Univ Nancy 1, CNRS, UMR 7555, Lab Chim Solide Mineral, F-54506 Vandoeuvre Les Nancy (France); Bernache-Assolant, D. [Ecole Natl Super Mines, F-42023 St Etienne (France)
2007-11-26
On the basis of optimized grinding/heating cycles developed for several phosphate-based ceramics, the preparation of brabantite and then monazite/brabantite solid solutions loaded with tetravalent thorium, uranium, and cerium (as a plutonium surrogate) was examined versus the heating temperature. The chemical reactions and transformations occurring when heating the initial mixtures of AnO{sub 2}/CeO{sub 2}, CaHPO{sub 4} center dot 2H{sub 2}O (or CaO), and NH{sub 4}H{sub 2}PO{sub 4} were identified through X-ray diffraction (XRD) and thermogravimetric/differential thermal analysis experiments. The incorporation of thorium, which presents only one stabilized oxidation state, occurs at 1100 degrees C. At this temperature, all the thorium-brabantite samples appear to be pure and single phase as suggested by XRD, electron probe micro-analyses, and {mu}-Raman spectroscopy. By the same method, tetravalent uranium can be also stabilized in uranium-brabantite, i.e., Ca{sub 0.5}U{sub 0.5}O{sub 4}, after heating at 1200 degrees C. Both brabantites, Ca{sub 0.5}Th{sub 0.5}PO{sub 4} and Ca{sub 0.5}U{sub 0.5}PO{sub 4}, begin to decompose when increasing the temperature to 1400 and 1300 degrees C, respectively, leading to a mixture of CaO and AnO{sub 2} by the volatilization of P{sub 4}O{sub 10}. In contrast to the cases of thorium and uranium, cerium(IV) is not stabilized during the heating treatment at high temperature. Indeed, the formation of Ca{sub 0.5}Ce{sub 0.5}PO{sub 4} appears impossible, due to the partial reduction of cerium(IV) into cerium(III) above 840 degrees C. Consequently, the systems always appear poly-phase, with compositions of (Ce{sup III}{sub 1-2x}Ce{sup IV}{sub x}Ca{sub x}PO{sub 4}) and Ca{sub 2}P{sub 2}O{sub 7}. The same conclusion can be also given when discussing the incorporation of cerium(IV) into La{sub 1-2x}Ce{sup III}{sub x-y}Ce{sub y}{sup IV}Ca{sub y}(PO{sub 4}){sub 1-x+y}. This incomplete incorporation of cerium(IV) confirms the results obtained
LIANG Xinhua; ZHU Ping; LIN Zhongqin; ZHANG Yan
2007-01-01
A lightweight automotive prototype using alter- native materials and gauge thickness is studied by a numeri- cal method. The noise, vibration, and harshness (NVH) performance is the main target of this study. In the range of 1-150 Hz, the frequency response function (FRF) of the body structure is calculated by a finite element method (FEM) to get the dynamic behavior of the auto-body structure. The pressure response of the interior acoustic domain is solved by a boundary element method (BEM). To find the most contrib- uting panel to the inner sound pressure, the panel acoustic contribution analysis (PACA) is performed. Finally, the most contributing panel is located and the resulting structural optimization is found to be more efficient.
Finite element analysis of fluid-structure interaction in buried liquid-conveying pipeline
朱庆杰; 陈艳华; 刘廷权; 代兆立
2008-01-01
Long distance buried liquid-conveying pipeline is inevitable to cross faults and under earthquake action,it is necessary to calculate fluid-structure interaction(FSI) in finite element analysis under pipe-soil interaction.Under multi-action of site,fault movement and earthquake,finite element model of buried liquid-conveying pipeline for the calculation of fluid structure interaction was constructed through combinative application of ADINA-parasolid and ADINA-native modeling methods,and the direct computing method of two-way fluid-structure coupling was introduced.The methods of solid and fluid modeling were analyzed,pipe-soil friction was defined in solid model,and special flow assumption and fluid structure interface condition were defined in fluid model.Earthquake load,gravity and displacement of fault movement were applied,also model preferences.Finite element research on the damage of buried liquid-conveying pipeline was carried out through computing fluid-structure coupling.The influences of pipe-soil friction coefficient,fault-pipe angle,and liquid density on axial stress of pipeline were analyzed,and optimum parameters were proposed for the protection of buried liquid-conveying pipeline.
Trace element analysis in rheumatoid arthritis under chrysotheraphy
Lecomte, R.; Paradis, P.; Monaro, S.; Barrette, M.; Lamoureux, G.; Menard, H.-A.
1981-03-01
Proton induced X-ray emission (PIXE) analysis is used to measure trace element concentrations in blood serum from patients with rheumatoid arthritis. Initially trace element contaminations in blood-collecting and storing devices are determined. Then mean values and nyctemeral cycles are measured both in normal subjects and patients with rheumatoid arthritis and other similar pathologies. Abnormal concentrations of Cu and Zn and anomalies in the nyctemeral cycle are found in the patients. In the second phase of the project, the special case of chrysotherapeutically treated (gold salt treatment) rheumatoid arthritis patients is studied for extended periods of time (up to 53 weeks).
Barbato, Michele; Conte, J P
2005-01-01
This paper focuses on a comparison between displacement-based and force-based elements for static and dynamic response sensitivity analysis of frame type structures. Previous research has shown that force-based frame elements are superior to classical displacement-based elements enabling, at no significant additional computational costs, a drastic reduction in the number of elements required for a given level of accuracy in the simulated response. The present work shows that this advantage of...
Ogra, Yasumitsu; Nagasaki, Shu; Yawata, Ayako; Anan, Yasumi; Hamada, Koichi; Mizutani, Akihiro
2016-04-01
We aimed to establish an element array analysis that involves the simultaneous detection of all elements in cells and the display of changes in element concentration before and after a cellular event. In this study, we demonstrated changes in element concentration during the differentiation of 3T3-L1 mouse fibroblasts into adipocytes. This metallomics approach yielded unique information of cellular response to physiological and toxicological events.
Adya Prasad Mishra; T K Balasubramanian
2001-10-01
Rovibrational matrix elements of the multipole moments ℓ up to rank 10 and of the linear polarizability of the H2 molecule in the condensed phase have been computed taking into account the effect of the intermolecular potential. Comparison with gas phase matrix elements shows that the effect of solid state interactions is marginal.
Stresses Analysis of Petroleum Pipe Finite Element under Internal Pressure
Dr.Ragbe.M.Abdusslam
2016-08-01
Full Text Available This paper described the results of a nonlinear static mode within ANSYS of elastic and elastic-plastic behaviour of thin petroleum pipe that is subjected to an internal pressure and therefore a linear stress analysis performed using ANSYS 9.0 finite element software Such an analysis is important because the shape of most structures under internal pressure is cylindrical[1]. In this paper is considered only. Elastic and elastic-plastic finite element analysis is used to predict the principle stresses, effective stress results are compared with those obtained from theatrical equations in order to predict the limit and failure loads for this type of loading also the relationships between redial, hoop stresses and displacement has been used to develop a through understanding. The analysis was completed using ANAYS Version 9.0. (a finite element program for Microsoft Windows NT. The program allows pre-processing, analysis and post-processing stages to be completed within a single application. The program can be used to model a large number of situations including buckling, plastic deformation, forming and stress analysis problems. r mm (In this study ,a thin pipe of internal radiu ri 596 .9 mmand of externalo 609 .6objected to aninternal pressure 2 i 4 .83 / mm which is gradually increased to near the ultimate load that may be sustained by the pipe. The pipe is modelled as an elasto-plastic material using the Von Mises yield criterion which is normally used for metallic materials[2]. The specification of the load in several increments enables the spread of the plasticity to occur gradually and its effect on the stress distribution to be assessed. Key words: finite element analysis, elastic-plastic behavior, thin walled pipe equivalent stress, TWT.
Stress recovery techniques for natural element method in 2-D solid mechanics
Cho, Jin Rae [Dept. of Naval Architecture and Ocean Engineering, Hongik University, Sejong (Korea, Republic of)
2016-11-15
This paper is concerned with the stress recovery for the natural element method in which the problem domain is discretized with Delaunay triangles and the structural behavior is approximated with Laplace interpolation functions. Basically, the global and local patch recovery techniques based on the L2-projection method are adopted. For the local patch recovery, the local element patches are defined by the supports of each Laplace interpolation function. For the comparison purpose, the local stress recovery is also performed using Lagrange-type basis functions that are used for 3- and 6-node triangular elements. The stresses that are recovered by the present global and local recovery techniques are compared each other and compared with the available analytic solution, in terms of their spatial distributions and the convergence rates. As well, the dependence of the recovered stress field on the type of test basis functions that are used forbnov-Galerkin (BG) and Petrov-Galerkin (PG) natural element methods is also investigated.
Extraction and elemental analysis of Coleus forskohlii extract
Haritha Kanne
2015-01-01
Full Text Available Background: Coleus forskohlii Willd. is a popular traditional medicine used since ancient times for treatment of heart diseases, abdominal colic and respiratory disorders. Objective: The aim of this study was to characterize the root extract of the medicinal plant Coleus forskohlii. Materials and Methods: Dry roots of C. forskohlii were used to extract Forskolin using toluene as a solvent. Thus, obtained extract of C. forskohlii was standardized to 30% and used for further studies. Results: The physical properties of the extract were analyzed through scanning electron microscopy analysis, while the characterization of root extract through X-ray diffraction (XRD and element analysis. The morphological feature of the C. forskohlii extract showed a flake like structure and the XRD showed sulfur trioxide (SO 3 and trimer of sulfur trioxide (S 3 O 9 . Through element analysis, elements such as carbon, oxygen, magnesium, aluminum, silicon, phosphorous, and sulfur were identified. Carbon showed the highest weight of 75.49% in comparison to all other elements.
Davranche, M.; Pourret, O.; Gruau, G.; Dia, A.
2006-12-01
Aquatic or soil organic matter are well-known to be strong adsorbent of many cations due to their adsorption capacity. Among these cations, the trivalent rare earth element (REE) and particularly Ce seem to be promising tools to investigate the impact of competition in between organic or inorganic ligands. Ce (III) is oxidized into Ce (IV) by oxidative surface such as Fe and Mn oxyhydroxides. Since Ce (IV) is preferentially adsorbed (as compared to other REE), a positive and negative Ce anomaly is developed respectively onto the solid and within the solution. Previous studies (Davranche et al., 2004, 2005) highlighted the suppression of this feature when Ce occurs to be complexed with organic matter (as humate species). Recent experiments were designed to evaluate the competition between humate and Mn oxide for REE complexation (each reactant being added simultaneously). Two parameters control the competition: time and pH. While organic matter does adsorb immediately the free REE, a desorption of REE occurs through time. Desorption is marked by the development of a Ce anomaly in the REE pattern that reflects the complexation with Mn oxide surface. Along the time, solid surface becomes thus more competitive than the organic matter. PH still influences the competition since at basic pH, REE and organic matter - probably as REE-organic complexes - are adsorbed onto the solid surface. Ultrafiltration analyses at 5 KD were also performed to separate organic matter and organic complexes from the solution. Results provide evidence that in presence of a solid surface, HREE (high rare earth element) desorption from the organic matter occurs through time. This leads to HREE enrichment in solution. All these results suggest that complexation of organic matter is kinetically favoured as compared to the complexation with solid surfaces. However, the organic complex formed during the first stage of the complexation process involves weak bindings. These bindings are easily broken
Nami, B. [Department of Materials and Metallurgical Engineering, Iran University of Science and Technology (IUST), Narmak, Tehran (Iran, Islamic Republic of); Shabestari, S.G., E-mail: shabestari@iust.ac.i [Department of Materials and Metallurgical Engineering, Iran University of Science and Technology (IUST), Narmak, Tehran (Iran, Islamic Republic of); Miresmaeili, S.M. [Department of Mechanical Engineering, Shahid Radjaei University, Lavizan, Tehran (Iran, Islamic Republic of); Razavi, H.; Mirdamadi, Sh. [Department of Materials and Metallurgical Engineering, Iran University of Science and Technology (IUST), Narmak, Tehran (Iran, Islamic Republic of)
2010-01-21
In the present study, the effects of rare earth (RE) elements on the microstructure and coarsening kinetics of the solid globular particle in the semisolid slurry of AZ91 magnesium alloy have been studied at 570 {sup o}C and 580 {sup o}C. The results showed that the coarsening kinetics of the solid globular particles in semisolid slurry of AZ91 alloy satisfies the Ostwald ripening theory. It was shown that the coarsening rate of the solid particles decreases by adding RE elements into AZ91 alloy, specially at 580 {sup o}C, which results in the smaller particles size. It was attributed to the solid-liquid interfacial energy reduction due to the addition of RE elements.
OXYGEN PRESSURE REGULATOR DESIGN AND ANALYSIS THROUGH FINITE ELEMENT MODELING
Asterios KOSMARAS
2017-05-01
Full Text Available Oxygen production centers produce oxygen in high pressure that needs to be defused. A regulator is designed and analyzed in the current paper for medical use in oxygen production centers. This study aims to design a new oxygen pressure regulator and perform an analysis using Finite Element Modeling in order to evaluate its working principle. In the design procedure,the main elements and the operating principles of a pressure regulator are taking into account. The regulator is designed and simulations take place in order to assessthe proposed design. Stress analysis results are presented for the main body of the regulator, as well as, flow analysis to determine some important flow characteristics in the inlet and outlet of the regulator.
Continuum damage growth analysis using element free Galerkin method
C O Arun; B N Rao; S M Srinivasan
2010-06-01
This paper presents an elasto-plastic element free Galerkin formulation based on Newton–Raphson algorithm for damage growth analysis. Isotropic ductile damage evolution law is used. A study has been carried out in this paper using the proposed element free Galerkin method to understand the effect of initial damage and its growth on structural response of single and bi-material problems. A simple method is adopted for enforcing EBCs by scaling the function approximation using a scaling matrix, when non-singular weight functions are used over the entire domain of the problem deﬁnition. Numerical examples comprising of one-and two-dimensional problems are presented to illustrate the effectiveness of the proposed method in analysis of uniform and non-uniform damage evolution problems. Effect of material discontinuity on damage growth analysis is also presented.
Arc-length technique for nonlinear finite element analysis
MEMON Bashir-Ahmed; SU Xiao-zu(苏小卒)
2004-01-01
Nonlinear solution of reinforced concrete structures, particularly complete load-deflection response, requires tracing of the equilibrium path and proper treatment of the limit and bifurcation points. In this regard, ordinary solution techniques lead to instability near the limit points and also have problems in case of snap-through and snap-back. Thus they fail to predict the complete load-displacement response. The arc-length method serves the purpose well in principle, Received wide acceptance in finite element analysis, and has been used extensively. However modifications to the basic idea are vital to meet the particular needs of the analysis. This paper reviews some of the recent developments of the method in the last two decades, with particular emphasis on nonlinear finite element analysis of reinforced concrete structures.
Dong, Yansheng; Wang, Yongqing; Dong, Limin; Jia, Peng; Lu, Fengcheng
2017-07-01
The nail with absorbable sheath (AS nail) is designed to reduce the stress shielding effect of internal fixation with interlocking intramedullary nail. In order to verify its feasibility, two types of the finite element models of internal fixation of tibia with the AS nail and the common metal nail (CM nail) are established using the Softwares of Mimics, Geomagic, SolidWorks and ANSYS according to the CT scanning data of tibia. The result of the finite element analysis shows that the AS nail has great advantages compared with the CM nail in reducing the stress shielding effect in different periods of fracture healing. The conclusion is that the AS nail can realize the static fixation to the dynamic fixation from the early to the later automatically to shorten the time of fracture healing, which also provides a new technique to the interlocking intramedullary nail.
An x ray scatter approach for non-destructive chemical analysis of low atomic numbered elements
Ross, H. Richard
1993-01-01
A non-destructive x-ray scatter (XRS) approach has been developed, along with a rapid atomic scatter algorithm for the detection and analysis of low atomic-numbered elements in solids, powders, and liquids. The present method of energy dispersive x-ray fluorescence spectroscopy (EDXRF) makes the analysis of light elements (i.e., less than sodium; less than 11) extremely difficult. Detection and measurement become progressively worse as atomic numbers become smaller, due to a competing process called 'Auger Emission', which reduces fluorescent intensity, coupled with the high mass absorption coefficients exhibited by low energy x-rays, the detection and determination of low atomic-numbered elements by x-ray spectrometry is limited. However, an indirect approach based on the intensity ratio of Compton and Rayleigh scattered has been used to define light element components in alloys, plastics and other materials. This XRS technique provides qualitative and quantitative information about the overall constituents of a variety of samples.
Finite Element Residual Stress Analysis of Planetary Gear Tooth
Jungang Wang
2013-01-01
Full Text Available A method to simulate residual stress field of planetary gear is proposed. In this method, the finite element model of planetary gear is established and divided to tooth zone and profile zone, whose different temperature field is set. The gear's residual stress simulation is realized by the thermal compression stress generated by the temperature difference. Based on the simulation, the finite element model of planetary gear train is established, the dynamic meshing process is simulated, and influence of residual stress on equivalent stress of addendum, pitch circle, and dedendum of internal and external meshing planetary gear tooth profile is analyzed, according to non-linear contact theory, thermodynamic theory, and finite element theory. The results show that the equivalent stresses of planetary gear at both meshing and nonmeshing surface are significantly and differently reduced by residual stress. The study benefits fatigue cracking analysis and dynamic optimization design of planetary gear train.
High-resolution analysis of protons scattered from solid surfaces
Matsunami, Noriaki; Kitoh, Kenshin (Dept. of Crystalline Materials Science, Engineering, Nagoya Univ. (Japan)); Kanasaki, Jun-ichi; Itoh, Noriaki (Physics Dept., Nagoya Univ. (Japan))
1990-01-01
A survey is given for new information that can be obtained by high energy-resolution analysis of protons backscattered from solid surfaces: layer-by-layer analysis of composition, atomic and electronic structures of surfaces. Optimization of the scattering yield leads to the result that scattering geometries of both glancing angle (PELS-I) and 180deg (PELS-II) are feasible. Results obtained by PELS-I are mainly described: Au atom location for Au/Si(111) and surface contraction of W(111). The impact parameter-dependent inelastic energy loss function is mentioned. (orig.).
Nonlinear Finite Element Analysis of Reinforced Concrete Shells
Mustafa K. Ahmed
2013-05-01
Full Text Available This investigation is to develop a numerical model suitable for nonlinear analysis of reinforced concrete shells. A nine-node Lagrangian element Figure (1 with enhanced shear interpolation will be used in this study. Table (1 describes shape functions and their derivatives of this element.An assumed transverse shear strain is used in the formulation of this element to overcome shear locking. Degenerated quadratic thick plate elements employing a layered discrelization through the thickness will be adopted. Different numbers of layers for different thickness can be used per element. A number of layers between (6 and 10 have proved to be appropriate to represent the nonlinear material behavior in structures. In this research 8 layers will be adequate. Material nonlinearities due to cracking of concrete, plastic flow or crushing of concrete in compression and yield condition of reinforcing steel are considered. The maximum tensile strength is used as a criterion for crack initiation. Attention is given to the tension stiffening phenomenon and the degrading effect of cracking on the compressive and shear strength of concrete. Perfect bond between concrete and steel is assumed. Attention is given also to geometric nonlinearities. An example have been chosen in order to demonstrate the suitability of the models by comparing the predicted behaviour with the experimental results for shell exhibiting various modes of failure.
Lafontaine, N. M.; Rossi, R.; Cervera, M.; Chiumenti, M.
2015-03-01
Low-order finite elements face inherent limitations related to their poor convergence properties. Such difficulties typically manifest as mesh-dependent or excessively stiff behaviour when dealing with complex problems. A recent proposal to address such limitations is the adoption of mixed displacement-strain technologies which were shown to satisfactorily address both problems. Unfortunately, although appealing, the use of such element technology puts a large burden on the linear algebra, as the solution of larger linear systems is needed. In this paper, the use of an explicit time integration scheme for the solution of the mixed strain-displacement problem is explored as an alternative. An algorithm is devised to allow the effective time integration of the mixed problem. The developed method retains second order accuracy in time and is competitive in terms of computational cost with the standard irreducible formulation.
Design Optimization Of Chain Sprocket Using Finite Element Analysis
Parag Nikam
2016-09-01
Full Text Available Chain sprocket is one of the important component of chain drive for transmitting power from one shaft to another. To ensure efficient power transmission chain sprocket should be properly designed and manufactured. There is a possibility of weight reduction in chain drive sprocket. In this study, chain sprocket is designed and analysed using Finite Element Analysis for safety and reliability. ANSYS software is used for static and fatigue analysis of sprocket design. Using these results optimization of sprocket for weight reduction has been done. As sprocket undergo vibration, modal analysis is performed
A multiscale finite element method for modeling fully coupled thermomechanical problems in solids
Sengupta, Arkaprabha
2012-05-18
This article proposes a two-scale formulation of fully coupled continuum thermomechanics using the finite element method at both scales. A monolithic approach is adopted in the solution of the momentum and energy equations. An efficient implementation of the resulting algorithm is derived that is suitable for multicore processing. The proposed method is applied with success to a strongly coupled problem involving shape-memory alloys. © 2012 John Wiley & Sons, Ltd.
Possible Way To Describe Breit's Interaction in Solids Composed From Heavy Elements
Kutepov, A L
2009-02-24
The report describes a theoretical procedure which could help evaluate the effect of quantum electrodynamic corrections on the electronic structure of crystals consisting of heavy elements. The procedure uses the effective Breit interaction as correction to traditional Coulomb interaction between electrons in non-relativistic theory. A number of other simplifying assumptions were made since even such a simplified consideration of quantum electrodynamic effects in crystals is a great challenge. These are as follows: (1) Exchange and correlation effects from the nonrelativistic interaction (the Coulomb term) between electrons are described within Density Functional Theory (DFT). (2) The Breit correction is on at the phase which involves the calculation of matrix elements between basis functions which define the single-electron spectrum of a crystal. In order to calculate the contribution from the Breit correction, the total wave function of electrons in the crystal is approximated by one Slater determinant consisting of the single-electron DFT-orbitals. (3) Only local matrix elements (i.e., the part of the two-electron integral for which both coordinate arguments belong to one and the same muffin-tin sphere) are considered.
Hughes, T. J. R.; Winget, J.; Levit, I.; Tezduyar, T. E.
1983-01-01
Element-by-element approximate factorization procedures are proposed for solving the large finite element equation systems which arise in computational mechanics. A variety of techniques are compared on problems of structural mechanics, heat conduction and fluid mechanics. The results obtained suggest considerable potential for the methods described.
Understanding compressive deformation behavior of porous Ti using finite element analysis
Roy, Sandipan; Khutia, Niloy [Department of Aerospace Engineering and Applied Mechanics, Indian Institute of Engineering Science and Technology, Shibpur (India); Das, Debdulal [Department of Metallurgy and Materials Engineering, Indian Institute of Engineering Science and Technology, Shibpur (India); Das, Mitun, E-mail: mitun@cgcri.res.in [Bioceramics and Coating Division, CSIR-Central Glass and Ceramic Research Institute, Kolkata (India); Balla, Vamsi Krishna [Bioceramics and Coating Division, CSIR-Central Glass and Ceramic Research Institute, Kolkata (India); Bandyopadhyay, Amit [W. M. Keck Biomedical Materials Research Laboratory, School of Mechanical and Materials Engineering, Washington State University, Pullman, WA 99164 (United States); Chowdhury, Amit Roy, E-mail: arcbesu@gmail.com [Department of Aerospace Engineering and Applied Mechanics, Indian Institute of Engineering Science and Technology, Shibpur (India)
2016-07-01
In the present study, porous commercially pure (CP) Ti samples with different volume fraction of porosities were fabricated using a commercial additive manufacturing technique namely laser engineered net shaping (LENS™). Mechanical behavior of solid and porous samples was evaluated at room temperature under quasi-static compressive loading. Fracture surfaces of the failed samples were analyzed to determine the failure modes. Finite Element (FE) analysis using representative volume element (RVE) model and micro-computed tomography (CT) based model have been performed to understand the deformation behavior of laser deposited solid and porous CP-Ti samples. In vitro cell culture on laser processed porous CP-Ti surfaces showed normal cell proliferation with time, and confirmed non-toxic nature of these samples. - Highlights: • Porous CP-Ti samples fabricated using additive manufacturing technique • Compressive deformation behavior of porous samples closely matches with micro-CT and RVE based analysis • In vitro studies showed better cell proliferation with time on porous CP-Ti surfaces.
Kadoura, Ahmad Salim
2013-06-01
In this work, a method to estimate solid elemental sulfur solubility in pure and gas mixtures using Monte Carlo (MC) molecular simulation is proposed. This method is based on Isobaric-Isothermal (NPT) ensemble and the Widom insertion technique for the gas phase and a continuum model for the solid phase. This method avoids the difficulty of having to deal with high rejection rates that are usually encountered when simulating using Gibbs ensemble. The application of this method is tested with a system made of pure hydrogen sulfide gas (H2S) and solid elemental sulfur. However, this technique may be used for other solid-vapor systems provided the fugacity of the solid phase is known (e.g., through experimental work). Given solid fugacity at the desired pressure and temperature, the mole fraction of the solid dissolved in gas that would be in chemical equilibrium with the solid phase might be obtained. In other words a set of MC molecular simulation experiments is conducted on a single box given the pressure and temperature and for different mole fractions of the solute. The fugacity of the gas mixture is determined using the Widom insertion method and is compared with that predetermined for the solid phase until one finds the mole fraction which achieves the required fugacity. In this work, several examples of MC have been conducted and compared with experimental data. The Lennard-Jones parameters related to the sulfur molecule model (ɛ, σ) have been optimized to achieve better match with the experimental work.
Transfinite element methodology towards a unified thermal/structural analysis
Tamma, K. K.; Railkar, S. B.
1986-01-01
The paper describes computational developments towards thermal/structural modeling and analysis via a generalized common numerical methodology for effectively and efficiently interfacing interdisciplinary areas. The proposed formulations use transform methods in conjunction with finite element developments for each of the heat transfer and structural disciplines, respectively, providing avenues for obtaining the structural response due to thermal effects. An alternative methodology for unified thermal/structural analysis is presented. The potential of the approach is outlined in comparison with conventional schemes and existing practices. Highlights and characteristic features of the approach are described via general formulations and applications to several problems. Results obtained demonstrate excellent agreement in comparison with analytic and/or conventional finite element schemes accurately and efficiently.
Basozabal, Itsaso; Guerreiro, Antonio; Gomez-Caballero, Alberto; Aranzazu Goicolea, M; Barrio, Ramón J
2014-08-15
A new potentiometric sensor based on molecularly imprinted nanoparticles produced via the solid-phase imprinting method was developed. For histamine quantification, the nanoparticles were incorporated within a membrane, which was then used to fabricate an ion-selective electrode. The use of nanoparticles with high affinity and specificity allowed for label-free detection/quantification of histamine in real samples with short response times. The sensor could selectively quantify histamine in presence of other biogenic amines in real wine and fish matrices. The limit of detection achieved was 1.12×10(-6)molL(-1), with a linear range between 10(-6) and 10(-2)molL(-1) and a response time below 20s, making the sensor as developed a promising tool for direct quantification of histamine in the food industry.
Nonlinear analysis of the forced response of structural elements
Nayfeh, A. H.; Mook, D. T.; Sridhar, S.
1974-01-01
A general procedure is presented for the nonlinear analysis of the forced response of structural elements to harmonic excitations. Internal resonances (i.e., modal interactions) are taken into account. All excitations are considered, with special consideration given to resonant excitations. The general procedure is applied to clamped-hinged beams. The results reveal that exciting a higher mode may lead to a larger response in a lower interacting mode, contrary to the results of linear analyses.
OOFEM – An Object Oriented Framework for Finite Element Analysis
B. Patzák
2004-01-01
Full Text Available This paper presents the design principles and structure of the object-oriented finite element software OOFEM, which has been under active development for several years. The main advantages of the presented framework include modular design, extensibility, and robustness. The code itself is freely available and is distributed under GNU public license. It provides tools for linear and nonlinear analysis of mechanical and transport problems on sequential and parallel computers.
Practical Application of Finite Element Analysis to Aircraft Structural Design
1986-08-01
analysis and mechanical properties, including the equivalent inclusion method, elastic constants and internal friction in composites, finite element...intensity factors are not available. The inclusion of fracture constraints in the automated design process is a logical extension of present structural...September 30-Dctober 3, 1975, Proceedings. Volume 1. (A78-19026 06-01) Turin, Libreria Editrice Universitaria Levrotto e Bella, 1975, p. 291-300. In
Finite Element Analysis Applied to Dentoalveolar Trauma: Methodology Description
2011-01-01
Dentoalveolar traumatic injuries are among the clinical conditions most frequently treated in dental practice. However, few studies so far have addressed the biomechanical aspects of these events, probably as a result of difficulties in carrying out satisfactory experimental and clinical studies as well as the unavailability of truly scientific methodologies. The aim of this paper was to describe the use of finite element analysis applied to the biomechanical evaluation of dentoalveolar traum...
Stochastic Finite Element Analysis of Plate and Shell Construction
无
2000-01-01
The response of random plate and shell construction is analyzed with the stochastic finite element method (SFEM). Random material properties and geometric dimensions of construction are involved in this paper. A simplified isoparametric local average model is used to describe the random field. Numerical results of the examples indicate that the approach presented herein is an economical and efficient solution for such an analysis compared with Monte Carlo simulation (MCS).
Better Finite-Element Analysis of Composite Shell Structures
Clarke, Gregory
2007-01-01
A computer program implements a finite-element-based method of predicting the deformations of thin aerospace structures made of isotropic materials or anisotropic fiber-reinforced composite materials. The technique and corresponding software are applicable to thin shell structures in general and are particularly useful for analysis of thin beamlike members having open cross-sections (e.g. I-beams and C-channels) in which significant warping can occur.
High-performance quantum-dot solids via elemental sulfur synthesis
Yuan, Mingjian
2014-03-21
An elemental-sulfur-based synthesis is reported, which, combined with processing to improve the size dispersion and passivation, results in a low-cost high-quality platform for small-bandgap PbS-CQD-based devices. Size-selective precipitation and cadmium chloride passivation are used to improve the power conversion efficiency of 1 eV bandgap CQD photovoltaic devices dramatically, which leads to record power conversion efficiency for a 1 eV PbS CQD solar cell of 5.4%. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.
High-performance quantum-dot solids via elemental sulfur synthesis.
Yuan, Mingjian; Kemp, Kyle W; Thon, Susanna M; Kim, Jin Young; Chou, Kang Wei; Amassian, Aram; Sargent, Edward H
2014-06-04
An elemental-sulfur-based synthesis is reported, which, combined with processing to improve the size dispersion and passivation, results in a low-cost high-quality platform for small-bandgap PbS-CQD-based devices. Size-selective precipitation and cadmium chloride passivation are used to improve the power conversion efficiency of 1 eV bandgap CQD photovoltaic devices dramatically, which leads to record power conversion efficiency for a 1 eV PbS CQD solar cell of 5.4%. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.
Gwinner, Joachim
2016-12-01
This contribution deals with unilateral contact problems with Tresca friction (given friction model) in hemitropic mi-cropolar elasticity. Based on a boundary integral approach such problems can be reduced to boundary variational inequalities. This suggests the use of boundary element methods for their numerical treatment. With higher order approximation this leads to a nonconforming approximation what can numerically be realized by means of Gauss-Lobatto quadrature. The contribution is based on the recent papers [7, 8] of the author and on joint work [3] with A. Gachechiladze, R. Gachechi-ladze, and D. Natroshvili.
Large areas elemental mapping by ion beam analysis techniques
Silva, T. F.; Rodrigues, C. L.; Curado, J. F.; Allegro, P.; Moro, M. V.; Campos, P. H. O. V.; Santos, S. B.; Kajiya, E. A. M.; Rizzutto, M. A.; Added, N.; Tabacniks, M. H.
2015-07-01
The external beam line of the Laboratory for Material Analysis with Ion Beams (LAMFI) is a versatile setup for multi-technique analysis. X-ray detectors for Particle Induced X-rays Emission (PIXE) measurements, a Gamma-ray detector for Particle Induced Gamma- ray Emission (PIGE), and a particle detector for scattering analysis, such as Rutherford Backscattering Spectrometry (RBS), were already installed. In this work, we present some results, using a large (60-cm range) XYZ computer controlled sample positioning system, completely developed and build in our laboratory. The XYZ stage was installed at the external beam line and its high spacial resolution (better than 5 μm over the full range) enables positioning the sample with high accuracy and high reproducibility. The combination of a sub-millimeter beam with the large range XYZ robotic stage is being used to produce elemental maps of large areas in samples like paintings, ceramics, stones, fossils, and all sort of samples. Due to its particular characteristics, this is a unique device in the sense of multi-technique analysis of large areas. With the continuous development of the external beam line at LAMFI, coupled to the robotic XYZ stage, it is becoming a robust and reliable option for regular analysis of trace elements (Z > 5) competing with the traditional in-vacuum ion-beam-analysis with the advantage of automatic rastering.
Finite Element Analysis of a Natural Fiber (Maize Composite Beam
D. Saravana Bavan
2013-01-01
Full Text Available Natural fiber composites are termed as biocomposites or green composites. These fibers are green, biodegradable, and recyclable and have good properties such as low density and low cost when compared to synthetic fibers. The present work is investigated on the finite element analysis of the natural fiber (maize composite beam, processed by means of hand lay-up method. Composite beam material is composed of stalk-based fiber of maize and unsaturated polyester resin polymer as matrix with methyl ethyl ketone peroxide (MEKP as a catalyst and Cobalt Octoate as a promoter. The material was modeled and resembled as a structural beam using suitable assumption and analyzed by means of finite element method using ANSYS software for determining the deflection and stress properties. Morphological analysis and X-ray diffraction (XRD analysis for the fiber were examined by means of scanning electron microscope (SEM and X-ray diffractometer. From the results, it has been found that the finite element values are acceptable with proper assumptions, and the prepared natural fiber composite beam material can be used for structural engineering applications.
Micro-scaled high-throughput digestion of plant tissue samples for multi-elemental analysis
Husted Søren
2009-09-01
Full Text Available Abstract Background Quantitative multi-elemental analysis by inductively coupled plasma (ICP spectrometry depends on a complete digestion of solid samples. However, fast and thorough sample digestion is a challenging analytical task which constitutes a bottleneck in modern multi-elemental analysis. Additional obstacles may be that sample quantities are limited and elemental concentrations low. In such cases, digestion in small volumes with minimum dilution and contamination is required in order to obtain high accuracy data. Results We have developed a micro-scaled microwave digestion procedure and optimized it for accurate elemental profiling of plant materials (1-20 mg dry weight. A commercially available 64-position rotor with 5 ml disposable glass vials, originally designed for microwave-based parallel organic synthesis, was used as a platform for the digestion. The novel micro-scaled method was successfully validated by the use of various certified reference materials (CRM with matrices rich in starch, lipid or protein. When the micro-scaled digestion procedure was applied on single rice grains or small batches of Arabidopsis seeds (1 mg, corresponding to approximately 50 seeds, the obtained elemental profiles closely matched those obtained by conventional analysis using digestion in large volume vessels. Accumulated elemental contents derived from separate analyses of rice grain fractions (aleurone, embryo and endosperm closely matched the total content obtained by analysis of the whole rice grain. Conclusion A high-throughput micro-scaled method has been developed which enables digestion of small quantities of plant samples for subsequent elemental profiling by ICP-spectrometry. The method constitutes a valuable tool for screening of mutants and transformants. In addition, the method facilitates studies of the distribution of essential trace elements between and within plant organs which is relevant for, e.g., breeding programmes aiming at
2-D Finite Element Analysis of Massive RC Structures
Saabye Ottosen, Niels
1982-01-01
Nonlinear analysis of concrete structures using finite elements is discussed. The applications include a thick-walled top-closure for a pressure vessel as well as the delicate problems of beams failing in shear. The top-closure analysis evaluates the effect of two different failure criteria...... and modeling of a realistic post-failure behavior is demonstrated to be mandatory for accurate structural predictions. For shear beams it is shown that the primary cause of failure is strain softening adjacent to the load point....
Estimation of elemental composition from proximate analysis of black liquor
Vakkilainen, E.K. [Andritz-Ahlstrom Corporation, Espoo (Finland)
2000-07-01
The black liquor properties will vary depending on the raw material used for pulping, the pulping conditions, the equipment used for pulping and the treatment of the liquor after the pulping. Accurate analysis of black liquor is needed to determine energy efficiency of o pulp mill, to calculate gas flows for environmental compliance reports and for production statistics. Black liquor composition and combustion properties can be estimated from known spread of data. Main source has been an internal company black liquor databank, which contains over 900 black liquor analysis. Regression equations for black liquor carbon, hydrogen, and inorganic element contents were derived. (orig.)
Finite Element Modeling Techniques for Analysis of VIIP
Feola, Andrew J.; Raykin, J.; Gleason, R.; Mulugeta, Lealem; Myers, Jerry G.; Nelson, Emily S.; Samuels, Brian C.; Ethier, C. Ross
2015-01-01
Visual Impairment and Intracranial Pressure (VIIP) syndrome is a major health concern for long-duration space missions. Currently, it is thought that a cephalad fluid shift in microgravity causes elevated intracranial pressure (ICP) that is transmitted along the optic nerve sheath (ONS). We hypothesize that this in turn leads to alteration and remodeling of connective tissue in the posterior eye which impacts vision. Finite element (FE) analysis is a powerful tool for examining the effects of mechanical loads in complex geometries. Our goal is to build a FE analysis framework to understand the response of the lamina cribrosa and optic nerve head to elevations in ICP in VIIP.
Analysis on Availability of the Carbon Element in Alcohol Production
郭素荣; 蒋大和; 寇刘秀; 陆雍森
2006-01-01
According to the concept of circular economy, the mass integration of alcohol production was investigated though the analysis of the carbon element contained in raw material cassava. Through the mass integration, the distillage wastewater turned into carbon resource and produced a great deal of by-product biogas while its chemical oxygen demand (COD) was reduced from 50000 mg/L to not more than 300 mg/L, the local secondary effluent standards, and other by-products such as CO2 (liquidized) and fusel oil were recovered. In the way, the consumption of raw material was only 2.2 tons cassava to produce 1 ton alcohol (96%, ψ) in the case study, much lower than the average level 2.92 t/t in China. The carbon element balance for production of alcohol was made through testing the concentrations of the carbon element of all mass flows. The results showed that the mass integration helped the availability of the carbon element increased from 44.74% to 64.75%.
Analysis of ingredient and heating value of municipal solid waste
无
2001-01-01
Great differences between municipal solid wastes(MSW) produced at different places and different times in terms of such parameters as physical ingredient and heating value lead to difficulty in effective handling of MSW. In this paper, ingredient,heating value and their temporal varying trends of typical MSW in Beijing were continuously measured and analyzed. With consideration of the process in pyrolysis and incineration, correlation between physical ingredients and heating values was induced, favorable for evaluation of heating value needed in handling of MSW from simple analysis of physical ingredients of it.
Multi-element pre-concentration of heavy metal ions by solid phase extraction on Chromosorb 108
Tuzen, Mustafa [Gaziosmanpasa University, Faculty of Science and Arts, Chemistry Department, 60250 Tokat (Turkey); Soylak, Mustafa [Erciyes University, Faculty of Art and Science, Department of Chemistry, 38039 Kayseri (Turkey)]. E-mail: soylak@erciyes.edu.tr; Elci, Latif [Pamukkale University, Faculty of Art and Science, Department of Chemistry, 20020 Denizli (Turkey)
2005-08-29
A multi-element preconcentration procedure for solid phase extraction on Chromosorb 108 as bathocuproinedisulfonic acid chelates and flame atomic absorption spectrometric determinations of some heavy metal ions in environmental samples is proposed in the present work. The influences of analytical parameters including pH of the aqueous solution, amounts of reagents, flow rates of sample and eluent solutions, sample volume etc. on the quantitative recoveries of copper, cadmium, lead, zinc, manganese, iron, chromium, nickel and cobalt ions were investigated. The effects of concomitant ions on the retentions of the analytes were also examined. The presented preconcentration procedure was applied to the determination of metal ions in reference standard materials (NRCC-SLRS 4 Riverine Water, SRM 1515 Apple leaves and GBW 07605 Tea) and some real samples including tap and river water, red wine, rice, black tea and honey.
Tanida, H
2001-01-01
In order to measure the extended X-ray absorption fine structure (EXAFS) spectrum of an ultra-diluted system, an optics and detector control system for a synchrotron radiation beamline is developed. The undulator gap width is continuously tuned to obtain the maximum X-ray photon flux during the energy scan for the EXAFS measurement. A piezoelectric translator optimizes the parallelism of the double crystal in a monochromator at each measurement point to compensate for mechanical errors of the monochromator, resulting in a smooth and intense X-ray photon flux during the measurement. For a detection of a weak fluorescence signal from diluted samples, a 19-element solid-state detector and digital signal processor are used. A K-edge EXAFS spectrum of iron in a myoglobin aqueous solution with a concentration of 5.58 parts per million was obtained by this system.
3D finite element analysis to detect stress distribution: spiral family implants.
Danza, Matteo; Zollino, Ilaria; Paracchini, Luigi; Riccardo, Guidi; Fanali, Stefano; Carinci, Francesco
2009-12-01
Spiral family implants are a root-form fixtures with increasing thickness of tread. This characteristic gives a self-tapping and self-condensing bone properties to implants. To study spiral family implant inserted in different bone quality and connected with abutments of different angulations a Finite Element Analysis (FEA) was performed. Once drawn the systems that were object of the study by CAD (Computer Aided Design), the FEA discretized solids composing the system in many infinitesimal little elementary solids defined finite elements. This lead to a mesh formation where the single finite elements were connected among them by nodes. For the 3 units bone-implant-abutments several thousand of tetrahedral elements having 10 parabolic nodes were employed. The biomechanical behaviour of 4.2 mm × 13 mm dental implants, connecting screw, straight and 15° and 25° angulated abutment subjected to static loads, in contact with high and poor bone quality was evaluated by FEA. A double system was analyzed: a) FY strength acting along Y axis and having 200 N intensity; b) FY and FZ couple of strengths applied along Y and Z directions and having respectively 200N and 140N intensity. The materials were considered as homogeneous, linear and isotropic. Then the FEA simulation was performed hypothesizing a linearity between loads and deformations. The lowest stress value was found in the system composed by implants and straight abutments loaded with a vertical strength, while the highest stress value were found in implants and 15° angulated abutment loaded with a angulated strength. In addition, the lower is the bone quality (i.e. D4) the higher is the distribution of the stress within the bone. Spiral family implants can be used successfully in low bone quality but a straight force is recommended.
Validated finite element analysis of the maverick total disc prosthesis.
Le Huec, Jean-Charles; Lafage, Virginie; Bonnet, Xavier; Lavaste, François; Josse, Loic; Liu, Minglyan; Skalli, Wafa
2010-06-01
Combining in vitro tests and finite element analysis to provide a more complete picture of the role that a disc prosthesis implant would play in the biomechanics of the spine. Analysis of the disc function after total disc prosthesis insertion with and without antero-posterior or lateral offset and in combination with adjacent fusion. To avoid the risk of degenerative cascade the total disc replacement may be considered as an alternative. Few finite element analysis combined with cadaver testing under loading conditions have been published today. In vitro tests were performed using 6 fresh human cadaver specimens to quantify the load-displacement behaviors before and after insertion of a total disc replacement (Maverick, Memphis) implant. A finite element (FE) spine model was validated with the data from the in vitro tests. This model is built on the basis of ANSYS software. The effect of the prosthesis positioning on the motion behavior at L4-L5 and on the inner loads over facets was evaluated in 4 configurations. The study showed that the motion behavior at the levels adjacent to the Maverick prosthesis remained the same as the intact spine, unlike a single level fusion at L5-S1. In the biomechanical study settings, Maverick prosthesis, once properly positioned, does not modify the motion behavior of the spine as compared with its intact state. The less-than-ideal positioning of the prosthesis, especially with anterior offset, affect significantly the range of motion of the spine segment and cause increase of inner load in the facets. Those results indicated a good reliability of the finite element model in representing both intact and instrumented spine segments. The in vitro test results demonstrated that Maverick disc prosthesis provides near physiologic function of a natural disc restores stability of the spine and preserves the segmental motion without undue stress on adjacent segments.To our knowledge, this study suggested for the first time the importance
Macro elemental analysis of food samples by nuclear analytical technique
Syahfitri, W. Y. N.; Kurniawati, S.; Adventini, N.; Damastuti, E.; Lestiani, D. D.
2017-06-01
Energy-dispersive X-ray fluorescence (EDXRF) spectrometry is a non-destructive, rapid, multi elemental, accurate, and environment friendly analysis compared with other detection methods. Thus, EDXRF spectrometry is applicable for food inspection. The macro elements calcium and potassium constitute important nutrients required by the human body for optimal physiological functions. Therefore, the determination of Ca and K content in various foods needs to be done. The aim of this work is to demonstrate the applicability of EDXRF for food analysis. The analytical performance of non-destructive EDXRF was compared with other analytical techniques; neutron activation analysis and atomic absorption spectrometry. Comparison of methods performed as cross checking results of the analysis and to overcome the limitations of the three methods. Analysis results showed that Ca found in food using EDXRF and AAS were not significantly different with p-value 0.9687, whereas p-value of K between EDXRF and NAA is 0.6575. The correlation between those results was also examined. The Pearson correlations for Ca and K were 0.9871 and 0.9558, respectively. Method validation using SRM NIST 1548a Typical Diet was also applied. The results showed good agreement between methods; therefore EDXRF method can be used as an alternative method for the determination of Ca and K in food samples.
Ronald M. Barrett
2012-01-01
Full Text Available This paper is centered on a new actuation mechanism which is integrated on a solid state rotor. This paper outlines the application of such a system via a Post-Buckled Precompression (PBP technique at the end of a twist-active piezoelectric rotor blade actuator. The basic performance of the system is handily modeled by using laminated plate theory techniques. A dual cantilevered spring system was used to increasingly null the passive stiffness of the root actuator along the feathering axis of the rotor blade. As the precompression levels were increased, it was shown that corresponding blade pitch levels also increased. The PBP cantilever spring system was designed so as to provide a high level of stabilizing pitch-flap coupling and inherent resistance to rotor propeller moments. Experimental testing showed pitch deflections increasing from just 8° peak-to-peak deflections at 650 V/mm field strength to more than 26° at the same field strength with design precompression levels. Dynamic testing showed the corner frequency of the linear system coming down from 63 Hz (3.8/rev to 53 Hz (3.2/rev. Thrust coefficients manipulation levels were shown to increase from 0.01 to 0.028 with increasing precompression levels. The paper concludes with an overall assessment of the actuator design.
Thermal buckling comparative analysis using Different FE (Finite Element) tools
Banasiak, Waldemar; Labouriau, Pedro [INTECSEA do Brasil, Rio de Janeiro, RJ (Brazil); Burnett, Christopher [INTECSEA UK, Surrey (United Kingdom); Falepin, Hendrik [Fugro Engineers SA/NV, Brussels (Belgium)
2009-12-19
High operational temperature and pressure in offshore pipelines may lead to unexpected lateral movements, sometimes call lateral buckling, which can have serious consequences for the integrity of the pipeline. The phenomenon of lateral buckling in offshore pipelines needs to be analysed in the design phase using FEM. The analysis should take into account many parameters, including operational temperature and pressure, fluid characteristic, seabed profile, soil parameters, coatings of the pipe, free spans etc. The buckling initiation force is sensitive to small changes of any initial geometric out-of-straightness, thus the modeling of the as-laid state of the pipeline is an important part of the design process. Recently some dedicated finite elements programs have been created making modeling of the offshore environment more convenient that has been the case with the use of general purpose finite element software. The present paper aims to compare thermal buckling analysis of sub sea pipeline performed using different finite elements tools, i.e. general purpose programs (ANSYS, ABAQUS) and dedicated software (SAGE Profile 3D) for a single pipeline resting on an the seabed. The analyses considered the pipeline resting on a flat seabed with a small levels of out-of straightness initiating the lateral buckling. The results show the quite good agreement of results of buckling in elastic range and in the conclusions next comparative analyses with sensitivity cases are recommended. (author)
Nonlinear explicit transient finite element analysis on the Intel Delta
Plaskacz, E.J. [Argonne National Lab., IL (United States); Ramirez, M.R.; Gupta, S. [Johns Hopkins Univ., Baltimore, MD (United States). Dept. of Civil Engineering
1993-03-01
Many large scale finite element problems are intractable on current generation production supercomputers. High-performance computer architectures offer effective avenues to bridge the gap between computational needs and the power of computational hardware. The biggest challenge lies in the substitution of the key algorithms in an application program with redesigned algorithms which exploit the new architectures and use better or more appropriate numerical techniques. A methodology for implementing nonlinear finite element analysis on a homogeneous distributed processing network is discussed. The method can also be extended to heterogeneous networks comprised of different machine architectures provided that they have a mutual communication interface. This unique feature has greatly facilitated the port of the code to the 8-node Intel Touchstone Gamma and then the 512-node Intel Touchstone Delta. The domain is decomposed serially in a preprocessor. Separate input files are written for each subdomain. These files are read in by local copies of the program executable operating in parallel. Communication between processors is addressed utilizing asynchronous and synchronous message passing. The basic kernel of message passing is the internal force exchange which is analogous to the computed interactions between sections of physical bodies in static stress analysis. Benchmarks for the Intel Delta are presented. Performance exceeding 1 gigaflop was attained. Results for two large-scale finite element meshes are presented.
Nonlinear explicit transient finite element analysis on the Intel Delta
Plaskacz, E.J. (Argonne National Lab., IL (United States)); Ramirez, M.R.; Gupta, S. (Johns Hopkins Univ., Baltimore, MD (United States). Dept. of Civil Engineering)
1993-01-01
Many large scale finite element problems are intractable on current generation production supercomputers. High-performance computer architectures offer effective avenues to bridge the gap between computational needs and the power of computational hardware. The biggest challenge lies in the substitution of the key algorithms in an application program with redesigned algorithms which exploit the new architectures and use better or more appropriate numerical techniques. A methodology for implementing nonlinear finite element analysis on a homogeneous distributed processing network is discussed. The method can also be extended to heterogeneous networks comprised of different machine architectures provided that they have a mutual communication interface. This unique feature has greatly facilitated the port of the code to the 8-node Intel Touchstone Gamma and then the 512-node Intel Touchstone Delta. The domain is decomposed serially in a preprocessor. Separate input files are written for each subdomain. These files are read in by local copies of the program executable operating in parallel. Communication between processors is addressed utilizing asynchronous and synchronous message passing. The basic kernel of message passing is the internal force exchange which is analogous to the computed interactions between sections of physical bodies in static stress analysis. Benchmarks for the Intel Delta are presented. Performance exceeding 1 gigaflop was attained. Results for two large-scale finite element meshes are presented.
BLAT-Based Comparative Analysis for Transposable Elements: BLATCAT
Sangbum Lee
2014-01-01
Full Text Available The availability of several whole genome sequences makes comparative analyses possible. In primate genomes, the priority of transposable elements (TEs is significantly increased because they account for ~45% of the primate genomes, they can regulate the gene expression level, and they are associated with genomic fluidity in their host genomes. Here, we developed the BLAST-like alignment tool (BLAT based comparative analysis for transposable elements (BLATCAT program. The BLATCAT program can compare specific regions of six representative primate genome sequences (human, chimpanzee, gorilla, orangutan, gibbon, and rhesus macaque on the basis of BLAT and simultaneously carry out RepeatMasker and/or Censor functions, which are widely used Windows-based web-server functions to detect TEs. All results can be stored as a HTML file for manual inspection of a specific locus. BLATCAT will be very convenient and efficient for comparative analyses of TEs in various primate genomes.
BLAT-based comparative analysis for transposable elements: BLATCAT.
Lee, Sangbum; Oh, Sumin; Kang, Keunsoo; Han, Kyudong
2014-01-01
The availability of several whole genome sequences makes comparative analyses possible. In primate genomes, the priority of transposable elements (TEs) is significantly increased because they account for ~45% of the primate genomes, they can regulate the gene expression level, and they are associated with genomic fluidity in their host genomes. Here, we developed the BLAST-like alignment tool (BLAT) based comparative analysis for transposable elements (BLATCAT) program. The BLATCAT program can compare specific regions of six representative primate genome sequences (human, chimpanzee, gorilla, orangutan, gibbon, and rhesus macaque) on the basis of BLAT and simultaneously carry out RepeatMasker and/or Censor functions, which are widely used Windows-based web-server functions to detect TEs. All results can be stored as a HTML file for manual inspection of a specific locus. BLATCAT will be very convenient and efficient for comparative analyses of TEs in various primate genomes.
Study on Tourist Carrying Capacity Based on Matter Element Analysis
LiuYunguo; FanTing; LiXin; ZhouMing; WangXianhai
2005-01-01
This paper proposes that it is necessary to implement the concept of tourist carrying capacity to facilitate the tourism planning, and presents a method to evaluate the carrying capacity. The method called matter element analysis can solve the uncertain and incompatible problem of the evaluated factors in assessing carrying capacity.The current state of a destination's carrying capacity can be determined by establishing the standard indexes and the matter element model. Through the evaluating of the travel industry zones of the Autonomous Prefecture of Western Hunan, the method is proved to be simple and feasible, and it is improved to be significant for the tourism planning and determination as well as the sustainable development of the regional tourism.
Finite element analysis applied to dentoalveolar trauma: methodology description.
da Silva, B R; Moreira Neto, J J S; da Silva, F I; de Aguiar, A S W
2011-01-01
Dentoalveolar traumatic injuries are among the clinical conditions most frequently treated in dental practice. However, few studies so far have addressed the biomechanical aspects of these events, probably as a result of difficulties in carrying out satisfactory experimental and clinical studies as well as the unavailability of truly scientific methodologies. The aim of this paper was to describe the use of finite element analysis applied to the biomechanical evaluation of dentoalveolar trauma. For didactic purposes, the methodological process was divided into steps that go from the creation of a geometric model to the evaluation of final results, always with a focus on methodological characteristics, advantages, and disadvantages, so as to allow the reader to customize the methodology according to specific needs. Our description shows that the finite element method can faithfully reproduce dentoalveolar trauma, provided the methodology is closely followed and thoroughly evaluated.
Probabilistic finite elements for fatigue and fracture analysis
Belytschko, Ted; Liu, Wing Kam
1993-01-01
An overview of the probabilistic finite element method (PFEM) developed by the authors and their colleagues in recent years is presented. The primary focus is placed on the development of PFEM for both structural mechanics problems and fracture mechanics problems. The perturbation techniques are used as major tools for the analytical derivation. The following topics are covered: (1) representation and discretization of random fields; (2) development of PFEM for the general linear transient problem and nonlinear elasticity using Hu-Washizu variational principle; (3) computational aspects; (4) discussions of the application of PFEM to the reliability analysis of both brittle fracture and fatigue; and (5) a stochastic computational tool based on stochastic boundary element (SBEM). Results are obtained for the reliability index and corresponding probability of failure for: (1) fatigue crack growth; (2) defect geometry; (3) fatigue parameters; and (4) applied loads. These results show that initial defect is a critical parameter.
Probabilistic finite elements for fatigue and fracture analysis. Final report
Belytschko, T.; Liu, W.K.
1993-04-01
An overview of the probabilistic finite element method (PFEM) developed by the authors and their colleagues in recent years is presented. The primary focus is placed on the development of PFEM for both structural mechanics problems and fracture mechanics problems. The perturbation techniques are used as major tools for the analytical derivation. The following topics are covered: (1) representation and discretization of random fields; (2) development of PFEM for the general linear transient problem and nonlinear elasticity using Hu-Washizu variational principle; (3) computational aspects; (4) discussions of the application of PFEM to the reliability analysis of both brittle fracture and fatigue; and (5) a stochastic computational tool based on stochastic boundary element (SBEM). Results are obtained for the reliability index and corresponding probability of failure for: (1) fatigue crack growth; (2) defect geometry; (3) fatigue parameters; and (4) applied loads. These results show that initial defect is a critical parameter.
Compositional data analysis for elemental data in forensic science.
Campbell, Gareth P; Curran, James M; Miskelly, Gordon M; Coulson, Sally; Yaxley, Gregory M; Grunsky, Eric C; Cox, Simon C
2009-07-01
Discrimination of material based on elemental composition was achieved within a compositional data (CoDa) analysis framework in a form appropriate for use in forensic science. The methods were carried out on example data from New Zealand nephrite. We have achieved good separation of the in situ outcrops of nephrite from within a well-defined area. The most significant achievement of working within the CoDa analysis framework is that the implications of the constraints on the data are acknowledged and dealt with, not ignored. The full composition was reduced based on collinearity of elements, principal components analysis (PCA) and scalings from a backwards linear discriminant analysis (LDA). Thus, a descriptive subcomposition was used for the final discrimination, using LDA, and proved to be more successful than using the full composition. The classification based on the LDA model showed a mean error rate of 2.9% when validated using a 10 repeat, three-fold cross-validation. The methods presented lend objectivity to the process of interpretation, rather than relying on subjective pattern matching type approaches.
Finite element analysis and structural design of pretensioned inverted T-beams with web openings
Hock Tian CHENG; Bashar S. MOHAMMED; Kamal Nasharuddin MUSTAPHA
2009-01-01
This paper presents the results of a research project aimed at providing standard circular web openings to the popular precast pretensioned inverted T-beam.Opening size and placement and required materials strengths were investigated. In this paper the nonlinear analysis and design of simply supported pretensioned inverted T-beam with circular web openings are presented.Two design parameters are varied: opening location and number of openings. The results from nonlinear finite element analysis were substantiated by test results from five pretensioned inverted T-beams with web opening and one solid beam. Good agreement is shown between the theoretical and the experimental results. The test results obtained from this investigation show that the performance of the specimens with web openings is almost identical to that of the specimen without web openings. A simple design method for pretensioned inverted T-beam with
Element Analysis of Instrumented Sharp Indentations into Pressure-sensitive Materials
Minh-Quy LE; Seock-Sam KIM
2007-01-01
Finite element analysis was carried out to investigate the conical indentation response of elastic-plastic solids within the framework of the hydrostatic pressure dependence and the power law strain hardening. A large number of 40 difierent combinations of elasto-plastic properties with n ranging from 0 to 0.5 and σy/E ranging from 0.0014 to 0.03 were used in the computations. The loading curvature C and the average contact pressure Pave were considered within the concept of representative strains and the dimensional analysis.Dimensionless functions associated with these two parameters were formulated for each studied value of the pressure sensitivity. The results for pressure sensitive materials lie between those for Von Mises materials and the elastic model.
STRESS ANALYSIS OF COMPOSITE PROPELLER BY USING FINITE ELEMENT ANALYSIS
B.SRIDHAR REDDY
2012-08-01
Full Text Available Present work proposes a methodology to design a propeller with a metal and composite material to analyze its strength and deformation using Ansys software. In order to evaluate the effectiveness of composite over metals, stress analysis is performed on both composite and metal propeller using Ansys. Proposed methodology showed substantial improvements in metal propellers. The mean deflection, normal stress and shear stress were found for both metallic and composite propeller by using Ansys. From the results, stressanalysis composite propeller is safe resonance phenomenon. In this work effort is made to reduce stress levels so that advantage of weight reduction along with stresses can be obtained. The comparison analysis of metallic and composite propeller was made for the maximum deformation and normal stresses.
Liu, Yang; D'Angelo, Ralph M.; Sinha, Bikash K.; Zeroug, Smaine
2017-02-01
Modeling and understanding the complex elastic-wave physics prevalent in solid-fluid cylindrically-layered structures is of importance in many NDE fields, and most pertinently in the domain of well integrity evaluation of cased holes in the oil and gas industry. Current sonic measurements provide viable techniques for well integrity evaluation yet their practical effectiveness is hampered by the current lack of knowledge of acoustic wave fields particularly in complicated cased-hole geometry where for instance two or more nested steel strings are present in the borehole. In this article, we propose and implement a Sweeping Frequency Finite Element Method (SFFEM) for acoustic guided waves simulation in complex geometries that include double steel strings cemented to each other and to the formation and where the strings may be non-concentric. Transient dynamic finite element models are constructed with sweeping frequency signals being applied as the excitation sources. The sources and receivers disposition simulate current sonic measurement tools deployed in the oilfield. Synthetic wavetrains are recorded and processed with modified matrix pencil method to isolate both the dispersive and non-dispersive propagating guided wave modes. Scaled experiments of fluid-filled double strings with dimensions mimicking the real ones encountered in the field have also been carried out to generate reference data. A comparison of the experimental and numerical results indicates that the SFFEM is capable of accurately reproducing the rich and intricate higher-order multiple wave fields observed experimentally in the fluid-filled double string geometries.
Pearson, Ian T.; Mottram, J. Toby
2012-01-01
A new modelling methodology is presented that enables the stiffness of adhesively bonded single lap-joints to be included in the finite element analysis of whole vehicle bodies. This work was driven by the need to significantly reduce computing resources for vehicle analysis. To achieve this goal the adhesive bond line and adherends are modelled by a relatively ‘small’ number of shell elements to replace the usual solid element mesh for a reliable analysis. Previous work in Part 1 has provide...
A Coupled Fluid-Structure Interaction Analysis of Solid Rocket Motor with Flexible Inhibitors
Yang, H. Q.; West, Jeff
2014-01-01
A capability to couple NASA production CFD code, Loci/CHEM, with CFDRC's structural finite element code, CoBi, has been developed. This paper summarizes the efforts in applying the installed coupling software to demonstrate/investigate fluid-structure interaction (FSI) between pressure wave and flexible inhibitor inside reusable solid rocket motor (RSRM). First a unified governing equation for both fluid and structure is presented, then an Eulerian-Lagrangian framework is described to satisfy the interfacial continuity requirements. The features of fluid solver, Loci/CHEM and structural solver, CoBi, are discussed before the coupling methodology of the solvers is described. The simulation uses production level CFD LES turbulence model with a grid resolution of 80 million cells. The flexible inhibitor is modeled with full 3D shell elements. Verifications against analytical solutions of structural model under steady uniform pressure condition and under dynamic condition of modal analysis show excellent agreements in terms of displacement distribution and eigen modal frequencies. The preliminary coupled result shows that due to acoustic coupling, the dynamics of one of the more flexible inhibitors shift from its first modal frequency to the first acoustic frequency of the solid rocket motor.
Direct analysis of silica by means of solid sampling graphite furnace atomic absorption spectrometry
Resano, M.; Mozas, E.; Crespo, C.; Pérez, J.; García-Ruiz, E.; Belarra, M. A.
2012-05-01
This paper reports on the use of solid sampling-graphite furnace atomic absorption spectrometry for the direct analysis of synthetic amorphous silica. In particular, determination of hazardous elements such As, Cd, Cr, Cu, Pb and Sb is investigated, as required by regulations of the food industry. The conclusion of the work is that, after proper optimization of the working conditions, paying particular attention to the atomization temperature and the use of proper modifiers (graphite powder, HNO3 or Pd), it is possible to develop suitable procedures that rely on the use of aqueous standard solutions to construct the calibration curves for all the elements investigated. The proposed method shows important benefits for the cost-effective analysis of such difficult samples in routine labs, permitting fast screening of those elements that are very rarely present in this type of sample, but also accurate quantification of those often found, while offering low limits of detection (always below 0.1 mg g- 1) that comply well with legal requirements, and precision levels that are fit for the purpose (approx. 6-9% R.S.D.).
A finite element model for thermomechanical analysis in casting processes
Celentano, D. (International Center for Numerical Methods in Engineering, E.T.S. d' Enginyers de Camins, Canals i Ports, Univ. Politecnica de Catalunya, Barcelona (Spain)); Oller, S. (International Center for Numerical Methods in Engineering, E.T.S. d' Enginyers de Camins, Canals i Ports, Univ. Politecnica de Catalunya, Barcelona (Spain)); Onate, E. (International Center for Numerical Methods in Engineering, E.T.S. d' Enginyers de Camins, Canals i Ports, Univ. Politecnica de Catalunya, Barcelona (Spain))
1993-11-01
This paper summarizes the recent work of the authors in the numerical simulation of casting processes. In particular, a coupled thermomechanical model to simulate the solidification problem in casting has been developed. The model, based on a general isotropic thermoelasto-plasticity theory and formulated in a macroscopical point of view, includes generalized phase-change effects and considers the different thermomechanical behaviour of the solidifying material during its evolution from liquid to solid. For this purpose, a phase-change variable, plastic evolution equations and a temperature-dependent material constitutive law have been defined. Some relevant aspects of this model are presented here. Full thermomechanical coupling terms have been considered as well as variable thermal and mechanical boundary conditions: the first are due to air gap formation, while the second involve a contact formulation. Particular details concerning the numerical implementation of this model are also mentioned. An enhanced staggered scheme, used to solve the highly non-linear fully coupled finite element equations, is proposed. Furthermore, a proper convergence criterion to stop the iteration process is adopted and, although the quadratic convergence of Newton-Rapshon's method is not achieved, several numerical experiments demonstrate reasonable convergence rates. Finally, an experimental cylindrical casting test problem, including phase-change phenomena, temperature-dependent constitutive properties and contact effects, is analyzed. Numerical results are compared with some laboratory measurements. (orig.).
Montecarlo simulation for a new high resolution elemental analysis methodology
Figueroa S, Rodolfo; Brusa, Daniel; Riveros, Alberto [Universidad de La Frontera, Temuco (Chile). Facultad de Ingenieria y Administracion
1996-12-31
Full text. Spectra generated by binary, ternary and multielement matrixes when irradiated by a variable energy photon beam are simulated by means of a Monte Carlo code. Significative jumps in the counting rate are shown when the photon energy is just over the edge associated to each element, because of the emission of characteristic X rays. For a given associated energy, the net height of these jumps depends mainly on the concentration and of the sample absorption coefficient. The spectra were obtained by a monochromatic energy scan considering all the emitted radiation by the sample in a 2{pi} solid angle, associating a single multichannel spectrometer channel to each incident energy (Multichannel Scaling (MCS) mode). The simulated spectra were made with Monte Carlo simulation software adaptation of the package called PENELOPE (Penetration and Energy Loss of Positrons and Electrons in matter). The results show that it is possible to implement a new high resolution spectroscopy methodology, where a synchrotron would be an ideal source, due to the high intensity and ability to control the energy of the incident beam. The high energy resolution would be determined by the monochromating system and not by the detection system and not by the detection system, which would basicalbe a photon counter. (author)
Analysis of bender element test interpretation using the discrete element method
O’Donovan, J.; O’Sullivan, C.; Marketos, G.; Muir Wood, D.
2015-01-01
While bender element testing is now well-established as a laboratory technique to determine soil stiffness, a robust technique to interpret the data remains elusive. A discrete element method (DEM) model of a face-centred cubic packing of uniform spheres was created to simulate bender element tests
Probabilistic Study of Bone Remodeling Using Finite Element Analysis
Werner, C.; Gorla, R. S. R.
2013-08-01
The dynamic bone remodeling process is a computationally challenging research area that struggles to understand the actual mechanisms. It has been observed that a mechanical stimulus in the bone greatly affects the remodeling process. A 3D finite element model of a femur is created and a probabilistic analysis is performed on the model. The probabilistic analysis measures the sensitivities of various parameters related to the material properties, geometric properties, and the three load cases defined as Single Leg Stance, Abduction, and Adduction. The sensitivity of each parameter is based on the calculated maximum mechanical stimulus and analyzed at various values of probabilities ranging from 0.001 to 0.999. The analysis showed that the parameters associated with the Single Leg Stance load case had the highest sensitivity with a probability of 0.99 and the angle of the force applied to the joint of the proximal femur had the overall highest sensitivity
A Textbook of Textbooks: Elements of Discourse Analysis
Jean Cristtus Portela
2015-10-01
Full Text Available This paper aims to analyze, from a semiotic perspective, José Luiz Fiorin's book Elementos de Análise do Discurso [Elements of Discourse Analysis] as a "textbook of textbooks," i.e., a textbook that gathers prototypical characteristics of teaching activities in undergraduate textbooks. Besides, it establishes a way to think and to teach the semiotics of discourse in Brazil. Starting from the analysis of the texts pertaining to the publishing activity, such as the book title, its cover, and the author's presentation, I came to an inventory and an analysis of the textual segments related to teaching that were conceived by the textbook enunciator, such as theoretical exemplification and explanation. The reading suggested here seeks to put in evidence and to understand the originality and the contemporaneity of the book, which turned 26 years old in 2015 and has played a strategic education role for many generations of semioticians and discourse analysts.
Finite element analysis of osteoporosis models based on synchrotron radiation
Xu, W.; Xu, J.; Zhao, J.; Sun, J.
2016-04-01
With growing pressure of social aging, China has to face the increasing population of osteoporosis patients as well as the whole world. Recently synchrotron radiation has become an essential tool for biomedical exploration with advantage of high resolution and high stability. In order to study characteristic changes in different stages of primary osteoporosis, this research focused on the different periods of osteoporosis of rats based on synchrotron radiation. Both bone histomorphometry analysis and finite element analysis were then carried on according to the reconstructed three dimensional models. Finally, the changes of bone tissue in different periods were compared quantitatively. Histomorphometry analysis showed that the structure of the trabecular in osteoporosis degraded as the bone volume decreased. For femurs, the bone volume fraction (Bone volume/ Total volume, BV/TV) decreased from 69% to 43%. That led to the increase of the thickness of trabecular separation (from 45.05μ m to 97.09μ m) and the reduction of the number of trabecular (from 7.99 mm-1 to 5.97mm-1). Simulation of various mechanical tests with finite element analysis (FEA) indicated that, with the exacerbation of osteoporosis, the bones' ability of resistance to compression, bending and torsion gradually became weaker. The compression stiffness of femurs decreased from 1770.96 Fμ m-1 to 697.41 Fμ m-1, the bending and torsion stiffness were from 1390.80 Fμ m-1 to 566.11 Fμ m-1 and from 2957.28N.m/o to 691.31 N.m/o respectively, indicated the decrease of bone strength, and it matched the histomorphometry analysis. This study suggested that FEA and synchrotron radiation were excellent methods for analysing bone strength conbined with histomorphometry analysis.
The application of finite element analysis on polydimethylsiloxane
Halim, Siti Aisyah Abdul; Yahud, Shuhaida; Muhamad, Wan Zuki Azman Wan; Daud, Ruslizam; Zain, Noor Alia Md
2015-05-01
An artificial skin should have the similarities of the human skin in term of biomechanical properties. In this paper, Polydimethysiloxane (PDMS) have been chosen as artificial skin material. PDMS specimens were prepared and the hardness of the material will be altered by adding different percentages of diluents to the mixture of the base and a cross-linker component. It indicated that the physiological elastic modulus depends strongly on the definition of the stress-strain curve, mixing ratio and strain rate. Tensile and compression test are conducted to find out the Hyperelastic (HE) coefficient and Young's modulus. These material coefficients will be used to define the constitutive model of PDMS for finite element analysis study. In this paper, three dimensional (3D) finite element (FE) stress and displacement analysis were used. Three types of models with different values of height were simulated in COMSOL MULTIPHYSICS. The analysis of the von Mises stress and surface deflection values revealed that maximum stress and maximum deflection concentration were located in the region near line load. PDMS polymer 10:1 is the softer product and can be commercialized as artificial skin material.
Finite Element Analysis of Connecting Rod of IC Engine
Samal Prasanta Kumar
2015-01-01
Full Text Available A connecting rod of IC engine is subjected to complex dynamic loading conditions. Therefore it is a critical machine element which attracts researchers’ attention. This paper aims at development of simple 3D model, finite element analyses and the optimization by intuition of the connecting rod for robust design. In this study the detailed load analysis under in-service loading conditions was performed for a typical connecting rod. The CAD model was prepared taking the detailed dimensions from a standard machine drawing text book. Based on the gas pressure variation in the cylinder of an IC engine, the piston forces were calculated for critical positions. MATLAB codes were written for this calculation. Altair Hypermesh and Hyperview were used for pre-processing and post-processing of the model respectively. The finite element analyses were performed using Altair Radioss. The results obtained were compared to a case study for the field failure of the connecting rod. By comparing the induced stress result with the yield strength of the material, the component was redesigned. This was done to save some mass keeping in mind that the induced stress value should be well below the yield strength of the material. The optimized connecting rod is 11.3% lighter than the original design.
Finite element model analysis of thermal failure in connector
WANG Xin; XU Liang-jun
2007-01-01
Thermal analysis and thermal diagnose are important for small power connector especially in electronic devices since their structure is usually compact. In this paper thermal behavior of small power connector was investigated. It was found that the contact resistance increased due to the Joule heating, and that increased contact resistance produced more Joule heating; this mutual action causes the connector to lose efficiency. The thermal distribution in the connector was analyzed using finite element method (FEM). The failure mechanism is discussed. It provides basis for improving the structure. The conclusion was verified by experimental results.
Nonlinear Finite Element Analysis of Pull-Out Test
Saabye Ottesen, N
1981-01-01
A specific pull-out test used to determine in-situ concrete compressive strength is analyzed. This test consists of a steel disc that is extracted from the structure. The finite element analysis considers cracking as well as strain hardening and softening in the pre- and post-failure region......, respectively. The aim is to attain a clear insight into structural behavior. Special attention is given to the failure mode. Severe cracking occurs and the stress distribution is very inhomogeneous. However, large compressive forces run from the disc in a rather narrow band towards the support...
Finite element analysis of inviscid subsonic boattail flow
Chima, R. V.; Gerhart, P. M.
1981-01-01
A finite element code for analysis of inviscid subsonic flows over arbitrary nonlifting planar or axisymmetric bodies is described. The code solves a novel primitive variable formulation of the coupled irrotationality and compressible continuity equations. Results for flow over a cylinder, a sphere, and a NACA 0012 airfoil verify the code. Computed subcritical flows over an axisymmetric boattailed afterbody compare well with finite difference results and experimental data. Interative coupling with an integral turbulent boundary layer code shows strong viscous effects on the inviscid flow. Improvements in code efficiency and extensions to transonic flows are discussed.
Extended Finite Element Method for Fracture Analysis of Structures
Mohammadi, Soheil
2008-01-01
This important textbook provides an introduction to the concepts of the newly developed extended finite element method (XFEM) for fracture analysis of structures, as well as for other related engineering applications.One of the main advantages of the method is that it avoids any need for remeshing or geometric crack modelling in numerical simulation, while generating discontinuous fields along a crack and around its tip. The second major advantage of the method is that by a small increase in number of degrees of freedom, far more accurate solutions can be obtained. The method has recently been
Finite element stress analysis of the CMS magnet coil
Desirelli, Alberto; Farinon, S; Levesy, B; Ps, C; Rey, J M; Sgobba, Stefano
2000-01-01
The Compact Muon Solenoid (CMS) is one of the experiments which are being designed in the framework of the Large Hadron Collider (LHC) project at CERN. The design field of the CMS magnet is 4 T, the magnetic length is 12.38 m and the aperture is 6.36 m. This is achieved with a 4 layer-5 module superconducting Al-stabilized coil energised at a nominal current of 20 kA. The finite element analysis (FEA) carried out is axisymmetric elasto-plastic. FEA has also been carried out on the suspension system and on the conductor. (8 refs).
Huang, M D; Krivan, V
2000-01-01
A direct solid sampling electrothermal atomic absorption spectrometry (SoS-ETAAS) method for ultratrace analysis of powdered niobium pentaoxide for Al, Co, Cr, Cu, Fe, K, Mg, Mn, Na, Ni and Zn has been developed. The elements K, Mg, Na and Zn could be determined without any chemical modification. However, in the determination of the elements Al, Co, Cr, Cu, Fe, Mn and Ni, serious matrix-caused non-spectral interferences and background occurred which made their determination impossible. This problem was remedied by conversion of the niobium pentaoxide matrix into the thermally stable niobium carbide by using methane atmosphere during the pyrolysis stage. The development resulted in establishing an extraordinary powerful method for the analysis of niobium pentaoxide in term of limits of detection, accuracy, simplicity and analysis time. Quantification was performed using calibration curves measured with aqueous standard solutions. The accuracy was checked by comparing the results with those obtained by ETAAS in analysis of slurries and digests of the sample. Due to almost complete freedom of blank and high applicable sample amounts (up to 15 mg), extremely low limits of detection (0.5-2 ng/g) were achieved.
Mirjankar, Nikhil S.; Fraga, Carlos G.; Carman, April J.; Moran, James J.
2016-01-08
Chemical attribution signatures (CAS) for chemical threat agents (CTAs) are being investigated to provide an evidentiary link between CTAs and specific sources to support criminal investigations and prosecutions. In a previous study, anionic impurity profiles developed using high performance ion chromatography (HPIC) were demonstrated as CAS for matching samples from eight potassium cyanide (KCN) stocks to their reported countries of origin. Herein, a larger number of solid KCN stocks (n = 13) and, for the first time, solid sodium cyanide (NaCN) stocks (n = 15) were examined to determine what additional sourcing information can be obtained through anion, carbon stable isotope, and elemental analyses of cyanide stocks by HPIC, isotope ratio mass spectrometry (IRMS), and inductively coupled plasma optical emission spectroscopy (ICP-OES), respectively. The HPIC anion data was evaluated using the variable selection methods of Fisher-ratio (F-ratio), interval partial least squares (iPLS), and genetic algorithm-based partial least squares (GAPLS) and the classification methods of partial least squares discriminate analysis (PLSDA), K nearest neighbors (KNN), and support vector machines discriminate analysis (SVMDA). In summary, hierarchical cluster analysis (HCA) of anion impurity profiles from multiple cyanide stocks from six reported country of origins resulted in cyanide samples clustering into three groups: Czech Republic, Germany, and United States, independent of the associated alkali metal (K or Na). The three country groups were independently corroborated by HCA of cyanide elemental profiles and corresponded to countries with known solid cyanide factories. Both the anion and elemental CAS are believed to originate from the aqueous alkali hydroxides used in cyanide manufacture. Carbon stable isotope measurements resulted in two clusters: Germany and United States (the single Czech stock grouped with United States stocks). The carbon isotope CAS is believed to
Carrilho, Leo A.; Dotto, Rosvita M. [Industrias Nucleares do Brasil SA, Resende, RJ (Brazil); Gouvea, Jayme P. de [Universidade Federal Fluminense, Volta Redonda, RJ (Brazil)
2000-07-01
Calculations of stresses and deformations of the bottom end piece of fuel elements of Angra-2 were performed with finite element method for the load case handling, zero load cold and full power operation, considering the same load of the actual and well established methodology, but applying shell elements instead of solid. The obtained results show that the application of this element is conservative and shall be used in future mechanical analysis of design alterations of this component when performed by the INB engineering group. (author)
Analysis of a Compessor Rotor using Finite Element Analysis
Munagunuri Suneel Babu
2014-11-01
Full Text Available The compressor compresses its working fluid by first accelerating the fluid and then diffusing it to obtain a pressure increase. In an axial flow compressor, air passes from one stage to the next, each stage raising the pressure slightly. The energy level of air or gas flowing through it is increased by the action of the rotor blades which exert a torque on the fluid which is supplied by an electric motor or a steam or a gas turbine. In this present work we are taken the existing model of transonic compressor test rotors which contains 18 blades. The model was modeled in Pro-E Creo 5.0 with existing dimensions and analyzed using Ansys14.5. For the analysis we are taken two different materials and compared the values. For the further extension we changed the existing mode by decreasing the number of blades and analyzed with different materials. The developed stress values of the existing model are compares with the modified models. Our objective is to increase the performance of the rotor blade by changing the materials and the model. From the observation we will suggest which model is suitable for the compressor rotor.
Probabilistic Finite Element Analysis & Design Optimization for Structural Designs
Deivanayagam, Arumugam
This study focuses on implementing probabilistic nature of material properties (Kevlar® 49) to the existing deterministic finite element analysis (FEA) of fabric based engine containment system through Monte Carlo simulations (MCS) and implementation of probabilistic analysis in engineering designs through Reliability Based Design Optimization (RBDO). First, the emphasis is on experimental data analysis focusing on probabilistic distribution models which characterize the randomness associated with the experimental data. The material properties of Kevlar® 49 are modeled using experimental data analysis and implemented along with an existing spiral modeling scheme (SMS) and user defined constitutive model (UMAT) for fabric based engine containment simulations in LS-DYNA. MCS of the model are performed to observe the failure pattern and exit velocities of the models. Then the solutions are compared with NASA experimental tests and deterministic results. MCS with probabilistic material data give a good prospective on results rather than a single deterministic simulation results. The next part of research is to implement the probabilistic material properties in engineering designs. The main aim of structural design is to obtain optimal solutions. In any case, in a deterministic optimization problem even though the structures are cost effective, it becomes highly unreliable if the uncertainty that may be associated with the system (material properties, loading etc.) is not represented or considered in the solution process. Reliable and optimal solution can be obtained by performing reliability optimization along with the deterministic optimization, which is RBDO. In RBDO problem formulation, in addition to structural performance constraints, reliability constraints are also considered. This part of research starts with introduction to reliability analysis such as first order reliability analysis, second order reliability analysis followed by simulation technique that
Thermodynamic cycle analysis of solid propellant air-turbo-rocket
CHEN Xiang; CHEN Yu-chun; TU Qiu-ye; ZHANG Hong; CAI Yuan-hu
2009-01-01
Solid propellant air-turbo-rocket (SPATR) is an air-breathing propulsion system. A numerical model of performance and characteristics analysis for SPATR was presented and the corresponding computer program was written according to the operation characteristics of SPATR. The influence on the SPATR performance at design point caused by the gas generator exit parameters and compressor pressure ratio had been computed and analyzed in detail. The off-design perform-ance of SPATR at sea level and high altitude had also been computed. The performance of thrust and specific impulse for SPATR with different solid propellant had been compared at off-design points, and the off-design performance comparison had been made between fuel-rich and oxygen-rich. The computation results indicated that SPATR operates within wide range of Maeh number (0 ～3) and altitude (0～12 km), and SPATR possesses high specific thrust (1 200 N/(kg/s)) and high specific impulse (7000 N/ (kg/s)) when fuel-air ratio of combustor equals fuel-air ratio.
Atomistic interpretation of solid solution hardening from spectral analysis.
Plendl, J N
1971-05-01
From analysis of a series of vibrational spectra of ir energy absorption and laser Raman, an attempt is made to interpret solid solution hardening from an atomistic point of view for the system CaF(2)/SrF(2). It is shown to be caused by the combined action of three atomic characteristics, i.e., their changes as a function of composition. They are deformation of the atomic coordination polyhedrons, overlap of the outer electron shells of the atom pairs, and the ratio of the ionic to covalent share of binding. A striking nonlinear behavior of the three characteristics, as a function of composition, gives maximum atomic bond strength to the 55/45 position of the system CaF(2)/SrF(2), in agreement with the measured data of the solid solution hardening. The curve for atomic bond strength, derived from the three characteristics, is almost identical to the curve for measured microhardness data. This result suggests that the atomistic interpretation, put forward in this paper, is correct.
Coupled Fluid-Structure Interaction Analysis of Solid Rocket Motor with Flexible Inhibitors
Yang, H. Q.; West, Jeff; Harris, Robert E.
2014-01-01
Flexible inhibitors are generally used in solid rocket motors (SRMs) as a means to control the burning of propellant. Vortices generated by the flow of propellant around the flexible inhibitors have been identified as a driving source of instabilities that can lead to thrust oscillations in launch vehicles. Potential coupling between the SRM thrust oscillations and structural vibration modes is an important risk factor in launch vehicle design. As a means to predict and better understand these phenomena, a multidisciplinary simulation capability that couples the NASA production CFD code, Loci/CHEM, with CFDRC's structural finite element code, CoBi, has been developed. This capability is crucial to the development of NASA's new space launch system (SLS). This paper summarizes the efforts in applying the coupled software to demonstrate and investigate fluid-structure interaction (FSI) phenomena between pressure waves and flexible inhibitors inside reusable solid rocket motors (RSRMs). The features of the fluid and structural solvers are described in detail, and the coupling methodology and interfacial continuity requirements are then presented in a general Eulerian-Lagrangian framework. The simulations presented herein utilize production level CFD with hybrid RANS/LES turbulence modeling and grid resolution in excess of 80 million cells. The fluid domain in the SRM is discretized using a general mixed polyhedral unstructured mesh, while full 3D shell elements are utilized in the structural domain for the flexible inhibitors. Verifications against analytical solutions for a structural model under a steady uniform pressure condition and under dynamic modal analysis show excellent agreement in terms of displacement distribution and eigenmode frequencies. The preliminary coupled results indicate that due to acoustic coupling, the dynamics of one of the more flexible inhibitors shift from its first modal frequency to the first acoustic frequency of the solid rocket motor
Solid waste dumping site suitability analysis using geographic ...
... system (GIS) and remote sensing for Bahir Dar Town, North Western Ethiopia. ... African Journal of Environmental Science and Technology ... Solid waste dumping is a serious problem in the urban areas because most solid wastes are not ...
Quantitative analysis of trace element concentrations in some gem-quality diamonds
McNeill, J.; Pearson, D. G.; Klein-Ben David, O.; Nowell, G. M.; Ottley, C. J.; Chinn, I.
2009-09-01
The geochemical signature of diamond-forming fluids can be used to unravel diamond-forming processes and is of potential use in the detection of so-called 'conflict' diamonds. While fluid-rich fibrous diamonds can be analyzed by a variety of techniques, very few data have been published for fluid-poor, gem-quality diamonds because of their very low impurity levels. Here we present a new ICPMS-based (ICPMS: inductively coupled plasma mass spectrometry) method for the analysis of trace element concentrations within fluid-poor, gem-quality diamonds. The method employs a closed-system laser ablation cell. Diamonds are ablated and the products trapped for later pre-concentration into solutions that are analyzed by sector-field ICPMS. We show that our limits of quantification for a wide range of elements are at the sub-pg to low pg level. The method is applied to a suite of 10 diamonds from the Cullinan Mine (previously known as Premier), South Africa, along with other diamonds from Siberia (Mir and Udachnaya) and Venezuela. The concentrations of a wide range of elements for all the samples (expressed by weight in the solid) are very low, with rare earth elements along with Y, Nb, Cs ranging from 0.01 to 2 ppb. Large ion lithophile elements (LILE) such as Rb and Ba vary from 1 to 30 ppb. Ti ranges from ppb levels up to 2 ppm. From the combined, currently small data set we observe two kinds of diamond-forming fluids within gem diamonds. One group has enrichments in LILE over Nb, whereas a second group has normalized LILE abundances more similar to those of Nb. These two groups bear some similarity to different groups of fluid-rich diamonds, providing some supporting evidence of a link between the parental fluids for both fluid-inclusion-rich and gem diamonds.
McEwen, Charles N; McKay, Richard G; Larsen, Barbara S
2005-12-01
Direct analysis of samples using atmospheric pressure ionization (API) provides a more rapid method for analysis of volatile and semivolatile compounds than vacuum solids probe methods and can be accomplished on commercial API mass spectrometers. With only a simple modification to either an electrospray (ESI) or atmospheric pressure chemical ionization (APCI) source, solid as well as liquid samples can be analyzed in seconds. The method acts as a fast solids/liquid probe introduction as well as an alternative to the new direct analysis in real time (DART) and desorption electrospray ionization (DESI) methods for many compound types. Vaporization of materials occurs in the hot nitrogen gas stream flowing from an ESI or APCI probe. Ionization of the thermally induced vapors occurs by corona discharge under standard APCI conditions. Accurate mass and mass-selected fragmentation are demonstrated as is the ability to obtain ions from biological tissue, currency, and other objects placed in the path of the hot nitrogen stream.
Elasto-plastic finite element analysis of squaring circular tube
HUANG Yuung-ming
2008-01-01
The flow rule of Prandtl-Reuss was adopted and incremental elasto-plastic finite-element analysis formulation of Coulomb's friction law combining the finite deformation theory was established,and Lagrangian formulation for simulating the squaring process of circular tube was updated.Incremental Coulomb's friction law was used in the global stiffness matrix to solve the sliding-sticking state of friction at the boundary contact interface.During the squaring process,the linear factor γmin was adopted to solve the non-linear boundary problems of changing node contact and separation,elasto-plastic transient situation in an element and the non-linear constitutive behavior of material so as to make each reasonable increment of the punch meet the demand of calculation for linear increment.The squaring process of circular tube,load distribution and final shape of work piece after unloading were simulated by this mode and compared with research data.It is known that the circular tube with higller geometrical ratio (R/t) could be pressed into symmetric square tube without collapse.This result can provide reference for the analysis of this process and evaluation and improvement of product defects.
Application of PIXE for elemental analysis of ancient Chinese artifacts
Lin, E.K. [Academia Sinica, Taipei (Taiwan). Inst. of Phys.; Wang, C.W. [Academia Sinica, Taipei (Taiwan). Inst. of Phys.; Yu, Y.C. [Academia Sinica, Taipei (Taiwan). Inst. of Phys.; Cheng, W.C. [Academia Sinica, Taipei (Taiwan). Inst. of Phys.; Chang, C.H. [Academia Sinica, Taipei (Taiwan). Inst. of Phys.; Yang, Y.C. [Academia Sinica, Taipei (Taiwan). Inst. of Phys.; Chang, C.Y. [Academia Sinica, Taipei (Taiwan). Inst. of Phys.
1995-05-01
Proton induced X-ray emission (PIXE) is a well-known method for elemental analysis in many different specimens for various applied studies. In this paper, we report an application of PIXE analysis for a series of ancient Chinese coins from the Tang Dynasty to the Ming Dynasty (AD 618-1679). Ninety-six PIXE spectra were obtained from forty-eight samples of the ancient coins with the use of a Ge(Li) X-ray detector. On each sample two spots at different positions on the flat surface were irradiated per run by 3 MeV protons from a NEC 9SDH-2 pelletron tandem accelerator. The principal component elements (Cu, Pb, Sn and Zn) and others (Fe, Sb, Ni and As) were determined for the analyzed coins. Variations in composition with a time span of about one thousand years for the examined coins were observed. The results are presented and aspects of the evolution of Chinese metallurgy in casting coins are discussed. (orig.).
Piyada Suwanpinij
2017-07-01
Full Text Available The dissolution of the microalloying elements in high strength low alloy steels is a cause of longer slab reheating time before hot forming processes compared with those for carbon steels. This is to ensure that all the necessary microalloying elements are dissolved and available for the precipitation hardening during and after the hot forming processes. In order to decrease the enormous amount of the reheating energy, which is the only heat required in the hot forming process, this works selects a high strength low alloy steel containing vanadium and analyses the dissolution kinetics by means of X-ray absorption spectroscopy (XAS. The XAS scans for other elements, i.e., titanium and nitrogen have been carried out and discussed for the possibility of the technique to investigate precipitates in microalloyed steels.Vanadium shows rapid dissolution kinetics that as soon as a lower reheating temperature of 1200 °C is reached, most of it is dissolved into the solid solution. This is opposite to titanium whose most fraction is still in TiN after long reheating time at higher temperature in accordance with the application of TiN for the grain boundary pinning during reheating. X-rays absorption near edge structure (XANES analysis of nitrogen shows different form of spectra before and after the reheating process. This indicates that the change in the coordination around the central nitrogen atoms takes place during the reheating interval.
无
2001-01-01
This paper describes recent work applying a taser ablation system (LSX-200) hyphenated with POEMS Ⅲ inductively coupled plasma mass spectrometry (LA-ICP-MS) for the in situ analysis of 22 trace elements of solid geological materials. It demonstrates the potential of LA-ICP-MS for the determination of geochemically important trace and ultra-trace elements following XRF routine sample preparation. Signal drift, difference in transport efficiency and sampling yield are well corrected with NIST SRM 612 as external calibration standard and Ca as internal standard. The obtained results agree to the recommended values with relative error better than 15 % and RSD less than 15 % for most determined trace elemems. LOD ranges from 0.021 × 10-6 to 0. 23 × 10-6 and less than 0.10 × 10-6 for majority trace elements determined. In addition, home-made macro functions including filter and calculator compiled by VBA language under Excel software greatly enhanced off-line data reduction efficiency.``
Cui, Zhuang; Yu, Bin; Li, Xue; Xu, Changpeng; Song, Jinqi; Ouyang, Hanbin; Diao, Xicai; Chen, Liguang
2012-11-01
To assess the optimal configuration of double-screw fixation for subtalar arthrodesis using finite element analysis. Three-dimensional finite element double-screw models of subtalar arthrodesis were reconstructed using Mimics 13.0, Geomagic 10.0 and solid works software based on the 3-D images of the volunteer's right foot. The external and internal rotation torques of 4 N·m were applied, and the micromotion at the bone-to-bone interface were measured to evaluate the initial stability of subtalar arthrodesis. A neck screw plus an anterolateral dome screw was the most stable model. The peak micromotion at the fusion site of this fixation configuration were 41.67mnplus;0.49 and 42.64mnplus;0.75 µm in response to the respectively. A neck screw plus a posteromedial dome screw was the least stable model, with peak micromotion at the bone-to-bone interface of 61.76mnplus;1.00 and 62.32mnplus;0.90 µm, respectively. A neck screw plus an anterolateral dome screw is the best fixation configuration while a neck screw plus a posteromedial screw provides the least stability of subtalar arthrodesis. Three-dimensional finite element models allow effective preoperative planning of the screw number and placement.
Finite element stress analysis of a compression mold. Final report. [Using SASL and WILSON codes
Watterson, C.E.
1980-03-01
Thermally induced stresses occurring in a compression mold during production molding were evaluated using finite element analysis. A complementary experimental stress analysis, including strain gages and thermocouple arrays, verified the finite element model under typical loading conditions.
Finite-element modeling and analysis in nanomedicine and dentistry.
Choi, Andy H; Conway, Richard C; Ben-Nissan, Besim
2014-08-01
This article aims to provide a brief background to the current applications of finite-element analysis (FEA) in nanomedicine and dentistry. FEA was introduced in orthopedic biomechanics in the 1970s in order to assess the stresses and deformation in human bones during functional loadings and in the design and analysis of implants. Since then, it has been applied with great frequency in orthopedics and dentistry in order to analyze issues such as implant design, bone remodeling and fracture healing, the mechanical properties of biomedical coatings on implants and the interactions at the bone-implant interface. More recently, FEA has been used in nanomedicine to study the mechanics of a single cell and to gain fundamental insights into how the particulate nature of blood influences nanoparticle delivery.
Finite Element Analysis of the 2 m Telescope Assemble
ZHAO Fu; WANG Ping; ZHAO Yue-jin; ZHANG Li; XIN Hong-bing
2007-01-01
To improve the performance of the 2 m telescope,the optimum design is applied to the telescope assemble.Referring to the telescope assemble with the dimetric truss,a group of reasonable sizes of the telescope assemble are found by optimization methods and modal analysis,which will raise the resonant frequency by 4.21%.As a result,the telescope assemble is less likely to resonate.Besides,the dynamic response module in ANSYS is utilized to analyze the modal type,harmonic vibration response and random vibration response of the telescope assemble.By the calculation of ANSYS,finite element analysis (FEA) method proves that the performance of the telescope assemble is mildly enhanced by means of optimum design.
Stability analysis of cracks propagating in three dimensional solids
Larralde, H.; Al-Falou, A.A.; Ball, R.C. [Cavendish Lab., Cambridge (United Kingdom)
1996-12-01
The authors present a theory for the morphology of the fracture surface left behind by slowly propagating cracks in linear, isotropic and homogeneous three dimensional solids. The results are based on first order perturbation theory of the equations of elasticity for cracks whose shape is slightly perturbed from planar. For cracks propagating under pure type 1 loading they find that all perturbation modes are linearly stable, from which they can predict the roughness of the fracture surface induced by fluctuations in the material. The authors compare their results with the classical results for cracks propagating in two dimensional systems, and discuss the effects in the three dimensional analysis which result from taking into account contributions from non-singular terms of the stress field, as well as the effects arising from finite speeds of crack propagation.
Structural finite element analysis of ITER In-wall shield
Shaikh, Moinuddin S., E-mail: moins@iter-india.org [ITER-India, Institute for Plasma Research, A-29, GIDC Electronic Estate, Sector 25, Gandhinagar 382016 (India); Pathak, H.A. [ITER-India, Institute for Plasma Research, A-29, GIDC Electronic Estate, Sector 25, Gandhinagar 382016 (India); Oliver, Tailhardat [Assystem EOS, Zac Saint Martin, 23 Rue Benjamin Franklin, 84120 Pertuis (France); Wang, Xiaoyu [ITER Organization, Route de Vinon sur Verdon, 13115 Saint Paul Lez Durance (France)
2013-10-15
The In-wall shielding (IWS) located between two shells of the vacuum vessel is part of the vacuum vessel of ITER. The function of the IWS is to provide neutron shielding and to reduce toroidal field ripple. The IWS plates are fastened using M30 bolts to hold them securely and the IWS blocks are mounted to the support ribs using the brackets and M20 bolts. The paper presents a structural finite element analysis of one sample IWS block carried out using ANSYS* to establish the benchmark analysis procedure of the IWS blocks. Boundary conditions are set taking into account the assembly procedure of the IWS blocks. The analysis is carried out in three load steps (1). Pretension on M30 (2). Pretension on M30 and M20 and (3) pretension on M30 and M20 plus Electromagnetic forces, dynamic forces, Seismic forces, etc. The stresses and displacements of individual IWS components are evaluated against their allowable stress limits as per an ASME guideline. The ITER-India’s results of analysis are compared with the ITER-IO’s results for the worst category 3-load step 3 and they are found comparable. This establishes the analysis procedure to be used for all of the IWS blocks.
Finite Element Analysis and Design Optimization of Connecting Rod
Ashwini Mane
2016-07-01
Full Text Available The objective of this study is to improve the design of connecting rod of single cylinder four stroke Otto cycle engine by shape optimization. The main objective of this study is weight reduction of connecting rod and improving its performance without affecting its functionality. Finite element analysis is one of the most important tools of CAD/CAM CAE. For this study ANSYS analysis software is used for modeling, analysis and shape design optimization. Initially, according to design considerations maximum loads were calculated for various maximum operating loading conditions. Calculated loads used as a loading condition in various load steps of FEM analysis. Stresses generated across all the locations of connecting rod evaluated using ANSYS Workbench. For optimization ANSYS Shape optimization module is used and extracted the required shape of connecting rod. Final CAD model of optimized connecting rod is prepared in Design Modeler. Static structural analysis of modified design is performed and the results compared with baseline design. After result are validated with the help of Modified Goodman’s Diagram. From the shape optimization we could able to achieve 14.73% weight reduction in existing connecting rod. Since the optimized design is having sufficient life, the design is much improved as compared to the existing design
A correlation for calculating elemental composition from proximate analysis of biomass materials
Jigisha Parikh; S.A. Channiwala; G.K. Ghosal [Sarvajanik College of Engineering and Technology, Surat (India). Chemical Engineering Department
2007-08-15
Elemental composition of biomass is an important property, which defines the energy content and determines the clean and efficient use of the biomass materials. However, the ultimate analysis requires very expensive equipments and highly trained analysts. The proximate analysis on the other hand only requires standard laboratory equipments and can be run by any competent scientist or engineer. This work introduces a general correlation, based on proximate analysis of biomass materials, to calculate elemental composition, derived using 200 data points and validated further for additional 50 data points. The entire spectrum of solid lignocellulosic materials have been considered in the derivation of the present correlation, which is given as: C = 0.637FC + 0.455VM, H = 0.052FC + 0.062VM, O = 0.304FC + 0.476VM, where FC - 4.7-38.4% fixed carbon, VM - 57.2-90.6% volatile matter, C - 36.2-53.1% carbon, H - 4.36-8.3% hydrogen and O - 31.37-49.5% oxygen in wt% on a dry basis. The average absolute error of these correlations are 3.21%, 4.79%, 3.4% and bias error of 0.21%, -0.15% and 0.49% with respect to measured values C, H and O, respectively. The major advantage of these correlations is their capability to compute elemental components of biomass materials from the simple proximate analysis and thereby provides a useful tool for the modeling of combustion, gasification and pyrolysis processes. 32 refs., 6 figs., 2 tabs.
Genome-wide analysis of core promoter elements from conserved human and mouse orthologous pairs
Jin, Victor X.; Singer, Gregory AC; Agosto-Pérez, Francisco J; Liyanarachchi, Sandya; Davuluri, Ramana V.
2006-01-01
Background The canonical core promoter elements consist of the TATA box, initiator (Inr), downstream core promoter element (DPE), TFIIB recognition element (BRE) and the newly-discovered motif 10 element (MTE). The motifs for these core promoter elements are highly degenerate, which tends to lead to a high false discovery rate when attempting to detect them in promoter sequences. Results In this study, we have performed the first analysis of these core promoter elements in orthologous mouse a...
Finite element analysis for general elastic multi-structures
无
2006-01-01
A finite element method is introduced to solve the general elastic multi-structure problem, in which the displacements on bodies, the longitudinal displacements on plates and the longitudinal displacements on beams are discretized using conforming linear elements, the rotational angles on beams are discretized using conforming elements of second order, the transverse displacements on plates and beams are discretized by the Morley elements and the Hermite elements of third order, respectively. The generalized Korn's inequality is established on related nonconforming element spaces, which implies the unique solvability of the finite element method. Finally, the optimal error estimate in the energy norm is derived for the method.
梁松坚; 王维; 王志泳; 刘亚俊
2013-01-01
To establish a digital research platform based on SolidWorks Simulation, then model and analyze human being's ankle in conditions of valgus and varus. Mimics10.01 was used for geometric reconstruction of the ankle based on the CT data of the foot. The model was meshed and assigned with the material properties in SolidWorks software, then imported to simulation. And the distortion situation of the ankle was simulated and analyzed in conditions of valgus and varus. The three-dimensional finite element model of the ankle established had good geometric similarity and could do mechanics analysis and measurement. The simulating results were turned out to be feasible. The mechanics simulation analysis of the human ankle based on SolidWorks Simulation is a effective and reliable method. It can improve the understanding of the mechanics mechanism and provide theoretical support for the clinic diagnosis and treatment of related diseases.%建立一个基于SolidWorks Simulation的数字化研究平台，对正常人体足踝在外翻和内翻状况下进行有限元建模与分析。用CT扫描图像提取志愿者骨骼边缘轮廓数据，利用软件Mimics10.01进行图象三维重建，再将足踝各骨的点云文件导入到SolidWorks软件，利用网格处理向导及曲面生成向导建立三维实体模型，并在对模型进行内翻与外翻状态下，用SolidWorks中的插件Simulation对足踝部分发生形变的过程进行模拟分析。建立的足踝三维有限元模型具有较好的几何相似性，能够进行力学分析和测量，模拟分析结果经验证是可行的。基于SolidWorks Simulation的人体踝骨模拟力学分析是个有效可靠的方法，能提高对其力学机制的认识，并为临床相关疾患的诊治提供理论支持。
Shkurenko, V. M.
1993-06-01
This paper presents the production scheme for heat- and erosion-protective carbon plastic materials for heat shield elements of solid-propellant nozzles. Attention is also given the method of manufacturing adhesive joint assemblies, and the production scheme is included.
A Parallel Multigrid Method for the Finite Element Analysis of Mechanical Contact
Hales, J D; Parsons, I D
2002-03-21
A geometrical multigrid method for solving the linearized matrix equations arising from node-on-face three-dimensional finite element contact is described. The development of an efficient implementation of this combination that minimizes both the memory requirements and the computational cost requires careful construction and storage of the portion of the coarse mesh stiffness matrices that are associated with the contact stiffness on the fine mesh. The multigrid contact algorithm is parallelized in a manner suitable for distributed memory architectures: results are presented that demonstrates the scheme's scalability. The solution of a large contact problem derived from an analysis of the factory joints present in the Space Shuttle reusable solid rocket motor demonstrates the usefulness of the general approach.
Compositional analysis of multi-element magnetic nanoparticles with a combined NMR and TEM approach
Gellesch, Markus; Hammerath, Franziska; Süß, Vicky; Haft, Marcel; Hampel, Silke; Wurmehl, Sabine; Büchner, Bernd
2017-09-01
The increasing interest in nanoscale materials goes hand in hand with the challenge to reliably characterize the chemical compositions and structural features of nanosized objects in order to relate those to their physical properties. Despite efforts, the analysis of the chemical composition of individual multi-element nanoparticles remains challenging—from the technical point of view as well as from the point of view of measurement statistics. Here, we demonstrate that zero-field solid-state nuclear magnetic resonance (NMR) complements local, single particle transmission electron microscopy (TEM) studies with information on a large assembly of chemically complex nanoparticles. The combination of both experimental techniques gives information on the local composition and structure and provides an excellent measurement statistic through the corresponding NMR ensemble measurement. This analytical approach is applicable to many kinds of magnetic materials and therefore may prove very versatile in the future research of particulate magnetic nanomaterials.
Relaxation behaviour of gasketed joints during assembly using ﬁnite element analysis
Muhammad Abid; Saad Hussain
2010-02-01
Gasketed bolted ﬂange pipe joints are always prone to leakage during operating conditions. Therefore, performance of a gasketed ﬂange joint is very much dependent on the proper joint assembly with proper gasket, proper gasket seating stress and proper pre-loading in the bolts of a joint. For a gasketed ﬂange joint, the two main concerns are the joint strength and the sealing capability. To investigate these, a detailed three-dimensional nonlinear ﬁnite element analysis of a gasketed joint is carried out using gasket as a solid plate. Bolt scatter, bolt bending and bolt relaxation are concluded as the main factors affecting the joint’s performance. In addition, the importance of proper bolt tightening sequence, number of passes inﬂuence of elastic and elasto-plastic material modelling on joint performance are also presented. A dynamic mode in a gasketed joint is concluded, which is the main reason for its failure.
Influence of laser beam focusing on LIBS efficiency at the elemental analysis of metals
Zhuravleva, V. I.; Rozantsev, V. A.; Ershov-Pavlov, E. A.
2007-06-01
Efficiency of the Laser-Induced Breakdown Spectroscopy (LIBS) has been studied as applied to the development of a technique for elemental microanalysis of solid samples, when a rather low consumption of the sample material is demanded allowing the technique to be practically non-destructive and applicable, e.g., at art, archaeological, forensic and similar investigations of unique objects. Higher intensity of the laser-induced emission spectra at lower sample erosion result in the increased efficiency of the LIBS analysis. The efficiency depends on many factors and in particular on thermal properties of the sample material and on its excitation conditions. Here, an influence of the laser beam focusing has been studied for samples of Al and Pb alloys having different thermal properties.
Multifractal and mechanical analysis of amorphous solid dispersions.
Adler, Camille; Teleki, Alexandra; Kuentz, Martin
2017-03-09
The formulation of lipophilic and hydrophobic compounds is a challenge for the pharmaceutical industry and it requires the development of complex formulations. Our first aim was to investigate hot-melt extrudate microstructures by means of multifractal analysis using scanning electron microscopy imaging. Since the microstructure can affect solid dosage form performance such as mechanical properties, a second objective was to study the influence of the type of adsorbent and of the presence of an amorphous compound on extrudate hardness. β-Carotene (BC) was chosen as poorly water-soluble model compound. Formulations containing a polymer, a lipid and two different silica based inorganic carriers were produced by hot-melt extrusion. Based on scanning electron microscopy/energy dispersive X-ray spectroscopy, the obtained images were analyzed using multifractal formalism. The breaking force of the strands was assessed by a three point bending test. Multifractal analysis and three point bending results showed that the nature of interparticle interactions in the inorganic carrier as well as the presence of amorphous BC had an influence on the microstructure and thus on the mechanical performance. The use of multifractal analysis and the study of the mechanical properties were complementary to better characterize and understand complex formulations obtained by hot-melt extrusion.
Headspace solid-phase microextraction for wine volatile analysis.
Azzi-Achkouty, Samar; Estephan, Nathalie; Ouaini, Naïm; Rutledge, Douglas N
2017-07-03
The most commonly used technique to prepare samples for the analysis of wine volatile is the headspace solid-phase microextraction (HS-SPME). This method has gained popularity in last few years, as it is a unique solventless preparation technique. In this paper, a summary of recently published studies using HS-SPME for the analysis of wine aromas, with special emphasis on the method developed, has been compiled. Several papers are discussed in detail, mainly with respect to the SPME conditions used. A brief summary of the reviews related to HS-SPME analysis is given and discussed. Several parameters affecting the HS-SPME, such as the salt concentration and the agitation conditions, are used in the same way as used in several papers. The HS-SPME extraction proved to be sufficiently sensitive to satisfy legislative requirements related to low detection and quantification limits as well as method accuracy and precision requirements. However, in order to achieve the best performance and precision, the protocol needs to be optimized for each case. The effect of different parameters must be well characterized to ensure correct extraction and desorption to ensure the transfer of extracted compounds into the analytical system. The operating parameters, such as time, temperature, and agitation, must then be kept constant for all the samples.
Feasibility of probing solid state nuclear tracks by thermal analysis method
YANG TongSuo; ZHOU Bing; YANG XinXin; HE ShaoRong; HENG ShuYun; YUAN SunSheng
2007-01-01
The feasibility of probing solid state nuclear tracks by thermal analysis method is discussed both theoretically and experimentally. Comparison is made between the thermal analysis method and the optical microscope method, and it is demonstrated that this thermal analysis method is applicable to probing solid state nuclear tracks.
PIXE-quantified AXSIA : elemental mapping by multivariate spectral analysis.
Doyle, Barney Lee; Antolak, Arlyn J. (Sandia National Labs, Livermore, CA); Campbell, J. L. (University of Guelph, Guelph, ON, Canada); Ryan, C. G. (CSIRO Exploration and Mining Bayview Road, Clayton VIC, Australia); Provencio, Paula Polyak; Barrett, Keith E. (Primecore Systems, Albuquerque, NM,); Kotula, Paul Gabriel
2005-07-01
Automated, nonbiased, multivariate statistical analysis techniques are useful for converting very large amounts of data into a smaller, more manageable number of chemical components (spectra and images) that are needed to describe the measurement. We report the first use of the multivariate spectral analysis program AXSIA (Automated eXpert Spectral Image Analysis) developed at Sandia National Laboratories to quantitatively analyze micro-PIXE data maps. AXSIA implements a multivariate curve resolution technique that reduces the spectral image data sets into a limited number of physically realizable and easily interpretable components (including both spectra and images). We show that the principal component spectra can be further analyzed using conventional PIXE programs to convert the weighting images into quantitative concentration maps. A common elemental data set has been analyzed using three different PIXE analysis codes and the results compared to the cases when each of these codes is used to separately analyze the associated AXSIA principal component spectral data. We find that these comparisons are in good quantitative agreement with each other.
BEM Analysis of Wave Propagation in a Water-Filled Borehole in an Anisotropic Solid
无
2007-01-01
This paper describes a time-domain boundary element method developed to analyze the interactions of acoustic and elastic waves near the interfaces between water and an anisotropic elastic solid. Two models are analyzed with one being the interface between two half spaces of fluid and solid and the other being a fluid region sandwiched by half space domains of anisotropic elastic solids. Both monopole and dipole point sources are used to generate an initial pressure wave in the fluid. Some snapshots of the transient wave behavior near the fluid-solid interfaces are given. The effect of the anisotropy in the solid on the pressure waveforms in the fluid is discussed. The numerical results allow detailed arrival identification and interpretation of acoustic and elastic waves propagating along the fluid-solid interfaces.
Zhang Yaoju [Department of Physics, Wenzhou Normal College, Wenzhou 325027 (China); Xiao Huaceng [Department of Biology, Wenzhou Normal College, Wenzhou 325027 (China); Zheng Chongwei [Department of Physics, Wenzhou Normal College, Wenzhou 325027 (China)
2004-07-01
The intensity distribution in near-field optical data storage with a solid immersion lens (SIL) and a binary phase-only diffractive super-resolution element (DSE) is expressed in a single definite integral by using angular spectrum theory. The super-resolution of binary two-zone phase DSEs for SIL systems is numerically studied for low and high numerical aperture (NA) systems. The results for the low-NA systems show that optimizing the zone boundary and phase of binary two-zone phase DSEs can decrease the spot size. The Strehl ratio, sidelobe intensity and axial characteristic length are also discussed. In addition, a binary two-zone phase filter can change the position of focus that shifts from the SIL-air interface to air, but the spot size increases. For the high-NA systems, the y- and z-polarized components of the transmitted field increase as the boundary and depth of phase of the DSE increase. When the phase boundary is smaller and the depth of phase depth is close to {pi}, super-resolving effect of DSE is more obvious but the intensity of sidelobes is larger for the high-NA system. In this way, it may be possible to improve both the resolution and focal depth of the SIL with high-NA systems.
Mostafa, Mostafa E.
2009-04-01
The finite cube elements method (FCEM) is a numerical tool designed for modelling gravity anomalies and estimating structural index (SI) of solid and fractal bodies with defined boundaries, tilted or in normal position and with variable density contrast. In this work, we apply FCEM to modelling magnetic anomalies and estimating SI of bodies with non-uniform magnetization having variable magnitude and direction. In magnetics as in gravity, FCEM allows us to study the spatial distribution of SI of the modelled bodies on contour maps and profiles. We believe that this will impact the forward and inverse modelling of potential field data, especially Euler deconvolution. As far as the author knows, this is the first time that gravity and magnetic anomalies, as well as SI, of self similar fractal bodies such as Menger sponges and Sierpinsky triangles are calculated using FCEM. The SI patterns derived from different order sponges and triangles are perfectly overlapped. This is true for bodies having variable property distributions (susceptibility or density contrast) under different field conditions (in case of magnetics) regardless of their orientation and depth of burial. We therefore propose SI as a new universal fractal-order-invariant measure which can be used in addition to the fractal dimensions for formulating potential field theory of fractal objects.
Essential trace elements in edible mushrooms by Neutron Activation Analysis
Moura, Patricia L.C.; Maihara, Vera A.; Castro, Lilian P. de [Instituto de Pesquisa e Energetica e Nucleares (IPEN/CNEN-SP), Sao Paulo, SP (Brazil)]. E-mail: patricialandim@ig.com.br; vmaihara@ipen.br; lilian.Pavanelli@terra.com.br; Figueira, Rubens C.L. [Universidade Cruzeiro do Sul, Sao Paulo, SP (Brazil)]. E-mail: figueiraru@yahoo.com.br
2007-07-01
Mushrooms are excellent nutritional sources since they provide proteins, fibers and mineral, such as K, P, Fe. They have also been the focus of medical research. In Brazil mushrooms are not consumed in large quantities by the general population since people know little about the nutritional and medicinal benefits that mushrooms offer. Hence, this study intends to contribute to a better understanding of the essential element content in edible mushrooms, which are currently commercialized in Sao Paulo state. Br Fe, K, Na and Zn concentrations were determined by Instrumental Neutron Activation Analysis in the following mushroom species: Shitake (Lentinus edodes), Shimeji (Pleurotus ssp), Paris Champignon (Agaricus bisporus), Hiratake ( Pleurotus ssp) and Eringue (Pleurotus Eryngu. The mushroom samples were acquired from commercial establishments in the city of Sao Paulo and directly from the producers. Essential element contents in mushrooms varied between Br 0.03 to 4.1 mg/kg; Fe 20 to 267 mg/kg; K 1.2 to 5.3 g/kg, Na 10 to 582 mg/kg and Zn 60 to 120 mg/kg. The results confirm that mushrooms can be considered a good source of K, Fe and Zn. The low Na level is a good nutritional benefit for the consumer. (author)
Three-dimensional finite element analysis of platform switched implant
2017-01-01
PURPOSE The purpose of this study was to analyze the influence of the platform switching concept on an implant system and peri-implant bone using three-dimensional finite element analysis. MATERIALS AND METHODS Two three-dimensional finite element models for wide platform and platform switching were created. In the wide platform model, a wide platform abutment was connected to a wide platform implant. In the platform switching model, the wide platform abutment of the wide platform model was replaced by a regular platform abutment. A contact condition was set between the implant components. A vertical load of 300 N was applied to the crown. The maximum von Mises stress values and displacements of the two models were compared to analyze the biomechanical behavior of the models. RESULTS In the two models, the stress was mainly concentrated at the bottom of the abutment and the top surface of the implant in both models. However, the von Mises stress values were much higher in the platform switching model in most of the components, except for the bone. The highest von Mises values and stress distribution pattern of the bone were similar in the two models. The components of the platform switching model showed greater displacement than those of the wide platform model. CONCLUSION Due to the stress concentration generated in the implant and the prosthodontic components of the platform switched implant, the mechanical complications might occur when platform switching concept is used. PMID:28243389
Two-Dimensional Nonlinear Finite Element Analysis of CMC Microstructures
Mital, Subodh K.; Goldberg, Robert K.; Bonacuse, Peter J.
2012-01-01
A research program has been developed to quantify the effects of the microstructure of a woven ceramic matrix composite and its variability on the effective properties and response of the material. In order to characterize and quantify the variations in the microstructure of a five harness satin weave, chemical vapor infiltrated (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, from which two dimensional finite element models were generated which approximated the actual specimen section geometry. A simplified elastic-plastic model, wherein all stress above yield is redistributed to lower stress regions, is used to approximate the progressive damage behavior for each of the composite constituents. Finite element analyses under in-plane tensile loading were performed to examine how the variability in the local microstructure affected the macroscopic stress-strain response of the material as well as the local initiation and progression of damage. The macroscopic stress-strain response appeared to be minimally affected by the variation in local microstructure, but the locations where damage initiated and propagated appeared to be linked to specific aspects of the local microstructure.
First Stage Solid Propellant Multiply Debris Thermal Analysis
Toleman, Benjamin M.
2011-01-01
Destruction of a solid rocket stage of a launch vehicle can create a thermal radiation hazard for an aborting crew module. This hazard was assessed for the Constellation Program (Cx) crew and launch vehicle concept. For this concept, if an abort was initiated in first stage flight, the Crew Module (CM) will separate and be pulled away from the malfunctioning launch vehicle via a Launch Abort System (LAS). Having aborted the mission, the launch vehicle will likely be destroyed via a Flight Termination System (FTS) in order to prevent it from errantly traversing back over land and posing a risk to the public. The resulting launch vehicle debris field, composed primarily of first stage solid propellant, poses a threat to the CM. The harsh radiative thermal environment, caused by surrounding burning propellant debris, may lead to CM parachute failure. A methodology, detailed herein, has been developed to address this concern and to quantify the risk of first stage propellant debris leading to the thermal demise of the CM parachutes. Utilizing basic thermal radiation principles, a software program was developed to calculate parachute temperature as a function of time for a given abort trajectory and debris piece trajectory set. Two test cases, considered worst case aborts with regard to launch vehicle debris environments, were analyzed using the simulation: an abort declared at Mach 1 and an abort declared at maximum dynamic pressure (Max Q). For both cases, the resulting temperature profiles indicated that thermal limits for the parachutes were not exceeded. However, short duration close encounters by single debris pieces did have a significant effect on parachute temperature. Therefore while these two test cases did not indicate exceedance of thermal limits, in order to quantify the risk of parachute failure due to radiative effects from the abort environment, a more thorough probability-based analysis using the methodology demonstrated herein must be performed.
First Stage Solid Propellant Multi Debris Thermal Analysis
Toleman, Benjamin M.
2011-01-01
The crew launch vehicle considered for the Constellation (Cx) Program utilizes a first stage solid rocket motor. If an abort is initiated in first stage flight the Crew Module (CM) will separate and be pulled away from the launch vehicle via a Launch Abort System (LAS) in order to safely and quickly carry the crew away from the malfunction launch vehicle. Having aborted the mission, the launch vehicle will likely be destroyed via a Flight Termination System (FTS) in order to prevent it from errantly traversing back over land and posing a risk to the public. The resulting launch vehicle debris field, composed primarily of first stage solid propellant, poses a threat to the CM. The harsh radiative thermal environment induced by surrounding burning propellant debris may lead to CM parachute failure. A methodology, detailed herein, has been developed to address this concern and quantify the risk of first stage propellant debris leading to radiative thermal demise of the CM parachutes. Utilizing basic thermal radiation principles, a software program was developed to calculate parachute temperature as a function of time for a given abort trajectory and debris piece trajectory set. Two test cases, considered worst-case aborts with regard to launch vehicle debris environments, were analyzed using the simulation: an abort declared at Mach 1 and an abort declared at maximum dynamic pressure (Max Q). For both cases, the resulting temperature profiles indicated that thermal limits for the parachutes were not exceeded. However, short duration close encounters by single debris pieces did have a significant effect on parachute temperature, with magnitudes on the order of 10 s of degrees Fahrenheit. Therefore while these two test cases did not indicate exceedance of thermal limits, in order to quantify the risk of parachute failure due to radiative effects from the abort environment, a more thorough probability-based analysis using the methodology demonstrated herein must be
Elemental and nutritional analysis of Punica granatum from Turkey.
Dumlu, Melek Ulusoylu; Gürkan, Elçin
2007-06-01
Twenty different varieties of pomegranate (Punica granatum) from Turkey were analyzed for vitamin C level, lipid content, sterol determination, anthocyanin content, and elemental analysis (Ca, Mg, P, Fe, Na, and K studies). Vitamin C content range of 1,050-312 mg/100 g, oil content range of 2.41-3.73%, sterol content range of 5.78-8.43%, anthocyanin content range of 2,100-4,400 mg/L, potassium range of 250-1,200 ppm, calcium range of 35-326 ppm, magnesium range of 176-427 ppm, iron range of 21-46 ppm, sodium range of 35-76 ppm, and phosphorus range of 12-43 ppm were observed in these varieties.
Studying apple bruise using a finite element method analysis
Pascoal-Faria, P.; Alves, N.
2017-07-01
Apple bruise damage from harvesting, handling, transporting and sorting is considered to be the major source of reduced fruit quality, resulting in a loss of profits for the entire fruit industry. Bruising is defined as damage and discoloration of fruit flesh, usually with no breach of the skin. The three factors which can physically cause fruit bruising are vibration, compression load and impact. The last one is the main source of bruise damage. Therefore, prediction of the level of damage, stress distribution and deformation of the fruits under external force has become a very important task. To address these problems a finite element analysis has been developed for studying Portuguese Royal Gala apple bruise. The results obtained will be suitable to apple distributors and sellers and will allow a reduction of the impact caused by bruise damage in apple annual production.
Recent directions of electrospray mass spectrometry for elemental speciation analysis
Schaumloeffel, Dirk [Universite de Pau et des Pays de l' Adour/CNRS UMR 5254, Laboratoire de Chimie Analytique Bio-Inorganique et Environnement/IPREM, Pau (France); Tholey, Andreas [Christian-Albrechts-Universitaet, Institute for Experimental Medicine - Div. Systematic Proteome Research, Kiel (Germany)
2011-06-15
A brief survey is given of the last 2 years' literature on electrospray mass spectrometry (ESI-MS) for speciation analysis. As observed for many years, the main recent applications in this field concern arsenic and selenium species, especially in studies encompassing combined use of molecular and element mass spectrometry. A further application field is the stoichiometric characterization of metal complexes by ESI-MS, which in some studies was assisted by nuclear magnetic resonance spectroscopy. A few examples are presented to illustrate arsenic species involved in metabolic pathways, sulfur species in oils and bitumen, and aluminum complexes. On the basis of this review, we also give an outlook of expected future developments and trends in this research field. (orig.)
Model order reduction techniques with applications in finite element analysis
Qu, Zu-Qing
2004-01-01
Despite the continued rapid advance in computing speed and memory the increase in the complexity of models used by engineers persists in outpacing them. Even where there is access to the latest hardware, simulations are often extremely computationally intensive and time-consuming when full-blown models are under consideration. The need to reduce the computational cost involved when dealing with high-order/many-degree-of-freedom models can be offset by adroit computation. In this light, model-reduction methods have become a major goal of simulation and modeling research. Model reduction can also ameliorate problems in the correlation of widely used finite-element analyses and test analysis models produced by excessive system complexity. Model Order Reduction Techniques explains and compares such methods focusing mainly on recent work in dynamic condensation techniques: - Compares the effectiveness of static, exact, dynamic, SEREP and iterative-dynamic condensation techniques in producing valid reduced-order mo...
Obtaining local reciprocal lattice vectors from finite-element analysis.
Sutter, John P; Connolley, Thomas; Hill, Tim P; Huang, Houcheng; Sharp, Doug W; Drakopoulos, Michael
2008-11-01
Finite-element analysis is frequently used by engineers at synchrotron beamlines to calculate the elastic deformation of a single crystal undergoing mechanical bending or thermal load. ANSYS Workbench software is widely used for such simulations. However, although ANSYS Workbench software provides useful information on the displacements, strains and stresses within the crystal, it does not yield the local reciprocal lattice vectors that would be required for X-ray diffraction calculations. To bridge this gap, a method based on the shape functions and interpolation procedures of the software itself has been developed. An application to the double-crystal bent Laue monochromator being designed for the I12 (JEEP) wiggler beamline at the Diamond Light Source is presented.
Ordinary chondrites - Multivariate statistical analysis of trace element contents
Lipschutz, Michael E.; Samuels, Stephen M.
1991-01-01
The contents of mobile trace elements (Co, Au, Sb, Ga, Se, Rb, Cs, Te, Bi, Ag, In, Tl, Zn, and Cd) in Antarctic and non-Antarctic populations of H4-6 and L4-6 chondrites, were compared using standard multivariate discriminant functions borrowed from linear discriminant analysis and logistic regression. A nonstandard randomization-simulation method was developed, making it possible to carry out probability assignments on a distribution-free basis. Compositional differences were found both between the Antarctic and non-Antarctic H4-6 chondrite populations and between two L4-6 chondrite populations. It is shown that, for various types of meteorites (in particular, for the H4-6 chondrites), the Antarctic/non-Antarctic compositional difference is due to preterrestrial differences in the genesis of their parent materials.
Finite Element Analysis of 6300 Deep Groove Ball Bearing
DENG Chi; YANG Guang-hui
2013-01-01
Rolling bearing is widely used in mechanical support, its general components are the inner ring, outer ring, the ball, retainer etc.. Now many companies in developed countries and university in the rolling bearing as the research object, and has made great progress in design theory, the experiment method and production technology etc. We will use the finite element ANSYS to establish the model of deep groove ball bearing. Through the contact analysis, we can get the contact stress between the rings and balls, strain, contact state, penetration, sliding distance and the friction stress distribution. These values are compared to the theoretical values with Hertz theory, and they have better consistency, provide the good theoretical basis for the optimization design of rolling bearings.
Finite element stress analysis of some ankle joint prostheses.
Falsig, J; Hvid, I; Jensen, N C
1986-05-01
A three-dimensional finite element stress analysis was employed to calculate stresses in a distal tibia modelled with three simple total ankle joint replacement tibial components. The bone was modelled as a composite structure consisting of cortical and trabecular bone in which the trabecular bone was either homogeneous with a constant modulus of elasticity or heterogenous with experimentally determined heterogeneity. The results were sensitive to variations in trabecular bone material property distributions, with lower stresses being calculated in the heterogeneous model. An anterolateral application of load, which proved the least favourable, was used in comparing the prosthetic variants. Normal and shear stresses at the trabecular bone-cement interface and supporting trabecular bone were slightly reduced by addition of metal backing to the polyethylene articular surface, and a further reduction to very low values was obtained by addition of a long intramedullary peg bypassing stresses to the cortical bone.
Finite element analysis on badminton racket design parameters
Nasruddin, Fakhrizal Azmy; Syahrom, Ardiyansyah; Abdul Kadir, Mohammed Rafiq; Omar, Abdul Hafidz; Öchsner, Andreas
2016-01-01
This work identifies the characteristics of racket design parameters that influence racket performance. It presents the finite element analysis of several designs of badminton rackets and compares them to experimental results for validation. Designing a racket requires a comprehensive understanding of racket performance characteristics. Essentially, racket performance is related to the sweet spot, which is the spot on the racket head that produces the most power and control when it strikes a shuttlecock. Determining a coefficient of restitution can help to identify the sweet spot on a racket. By analyzing several head shape designs, it becomes apparent that isometric head shape rackets produce better coefficients of restitution compared to oval and round ones. It is recommended that the racket design consist of low string tension, stiffer racket shafts and bigger head size in order to produce higher shuttlecock speed.
SOLIDS PRECIPITATION EVENT IN MCU CAUSAL ANALYSIS AND RECOMMENDATIONS FROM SOLIDS RECOVERY TEAM
Garrison, A.; Aponte, C.
2014-08-15
A process upset occurred in the Modular Caustic-Side Solvent Extraction Unit (MCU) facility on April 6th, 2014. During recovery efforts, a significant amount of solids were found in the Salt Solution Feed Tank (SSFT), Salt Solution Receipt Tanks (SSRTs), two extraction contactors, and scrub contactors. The solids were identified by Savannah River National Laboratory (SRNL) as primarily sodium oxalate and sodium alumina silicate (NAS) with the presence of some aluminum hydroxide. NAS solids have been present in the SSFT since simulant runs during cold chemical startup of MCU in 2007, and have not hindered operations since that time. During the process upset in April 2014, the oxalate solids partially blocked the aqueous outlet of the extraction contactors, causing salt solution to exit through the contactor organic outlet to the scrub contactors with the organic phase. This salt solution overwhelmed the scrub contactors and passed with the organic phase to the strip section of MCU. The partially reversed flow of salt solution resulted in a Strip Effluent (SE) stream that was high in Isopar™ L, pH and sodium. The primary cause of the excessive solids accumulation in the SSRTs and SSFT at MCU is attributed to an increase in the frequency of oxalic acid cleaning of the 512-S primary filter. Agitation in the SSRTs at MCU in response to cold weather likely provided the primary mechanism to transfer the solids to the contactors. Sources of the sodium oxalate solids are attributed to the oxalic acid cleaning solution used to clean the primary filter at the Actinide Removal Process (ARP) filtration at 512-S, as well as precipitation from the salt batch feed, which is at or near oxalate saturation. The Solids Recovery Team was formed to determine the cause of the solids formation and develop recommendations to prevent or mitigate this event in the future. A total of 53 recommendations were generated. These recommendations were organized into 4 focus areas: • Improve
Data analysis methods for solid-state nanopores
Plesa, Calin; Dekker, Cees
2015-02-01
We describe a number of techniques for the analysis of solid-state nanopore ionic current traces and introduce a new package of Matlab analysis scripts with GUI front ends. We discuss methods for the detection of the local baseline and propose a new detection algorithm that bypasses some of the classical weaknesses of moving-average detection. Our new approach removes detected events and re-creates an ideal event-free baseline subsequently used to recalculate the local baseline. Iterative operation of this algorithm causes both the moving average of the baseline current and its standard deviation to converge to their correct values. We explain different approaches to selecting events and building event populations, and we show the value of keeping track of the changes in parameters, such as the event rate and the pore resistance, throughout the course of the experiment. Finally, we introduce a new technique for separating unfolded events and detecting current spikes present within translocation events. This open source software package is available online at: http://ceesdekkerlab.tudelft.nl/downloads/
Composite analysis for solid waste storage area 6
Lee, D.W.
1997-09-01
The composite analysis (CA) provides an estimate of the potential cumulative impacts to a hypothetical future member of the public from the Solid Waste Storage Area 6 (SWSA 6) disposal operations and all of the other sources of radioactive material in the ground on the ORR that may interact with contamination originating in SWSA 6.The projected annual dose to hypothetical future member of the public from all contributing sources is compared to the primary dose limit of 100 mrem per year and a dose constraint of 30 mrem per year. Consistent with the CA guidance, dose estimates for the first 1000 years after disposal are emphasized for comparison with the primary dose limit and dose constraint.The current land use plan for the ORR is being revised, and may include a reduction in the land currently controlled by DOE on the ORR. The possibility of changes in the land use boundary is considered in the CA as part of the sensitivity and uncertainty analysis of the results, the interpretation of results, and the conclusions.
Thermodynamic Analysis of the Gasification of Municipal Solid Waste
Pengcheng Xu
2017-06-01
Full Text Available This work aims to understand the gasification performance of municipal solid waste (MSW by means of thermodynamic analysis. Thermodynamic analysis is based on the assumption that the gasification reactions take place at the thermodynamic equilibrium condition, without regard to the reactor and process characteristics. First, model components of MSW including food, green wastes, paper, textiles, rubber, chlorine-free plastic, and polyvinyl chloride were chosen as the feedstock of a steam gasification process, with the steam temperature ranging from 973 K to 2273 K and the steam-to-MSW ratio (STMR ranging from 1 to 5. It was found that the effect of the STMR on the gasification performance was almost the same as that of the steam temperature. All the differences among the seven types of MSW were caused by the variation of their compositions. Next, the gasification of actual MSW was analyzed using this thermodynamic equilibrium model. It was possible to count the inorganic components of actual MSW as silicon dioxide or aluminum oxide for the purpose of simplification, due to the fact that the inorganic components mainly affected the reactor temperature. A detailed comparison was made of the composition of the gaseous products obtained using steam, hydrogen, and air gasifying agents to provide basic knowledge regarding the appropriate choice of gasifying agent in MSW treatment upon demand.
Finite Element Analysis of Wrinkled Membrane Structures for Sunshield Applications
Johnston, John D.; Brodeur, Stephen J. (Technical Monitor)
2002-01-01
The deployable sunshield is an example of a gossamer structure envisioned for use on future space telescopes. The basic structure consists of multiple layers of pretensioned, thin-film membranes supported by deployable booms. The prediction and verification of sunshield dynamics has been identified as an area in need of technology development due to the difficulties inherent in predicting nonlinear structural behavior of the membranes and because of the challenges involved. in ground testing of the full-scale structure. This paper describes a finite element analysis of a subscale sunshield that has been subjected to ground testing in support of the Next Generation Space Telescope (NGST) program. The analysis utilizes a nonlinear material model that accounts for wrinkling of the membranes. Results are presented from a nonlinear static preloading analysis and subsequent dynamics analyses to illustrate baseline sunshield structural characteristics. Studies are then described which provide further insight into the effect of membrane. preload on sunshield dynamics and the performance of different membrane modeling techniques. Lastly, a comparison of analytical predictions and ground test results is presented.
Finite element analysis for radiative heat transfer in multidimensional participating media
无
2007-01-01
A finite element model is developed to simulate the radiative transfer in 2D and 3D complex-geometric enclosure filled with absorbing and scattering media. This model is based on the discrete ordinates method and finite element theory. The finite element formulations and detailed steps of numerical calculation are given.The discrepancy of the results produced by different space and solid angle discretization is also investigated and compared. The effect of the six-node quadric element on the accuracy is analyzed by a 2D rectangular enclosure. These results indicate that the present model can simulate radiative transfer in multidimensional complexgeometric enclosure with participating media effectively and accurately.
A Finite Element Analysis of Optimal Variable Thickness Sheets
Petersson, Joakim S
1996-01-01
A quasimixed Finite Element (FE) method for maximum stiffness of variablethickness sheets is analysed. The displacement is approximated with ninenode Lagrange quadrilateral elements and the thickness is approximated aselementwise constant. One is guaranteed that the FE displacement solutionswill...
Finite Element Analysis of Deformed Legs of Offshore Platform Structures
柳春图; 秦太验; 段梦兰
2002-01-01
The element stiffness matrix of the equivalent beam or pipe element of the deformed leg of the platform is derived bythe finite element method. The stresses and displacements of some damaged components are calculated, and the numeri-cal solutions agree well with those obtained by the fine mesh finite element method. Finally, as an application of thismethod, the stresses of some platform structures are calculated and analyzed.
Wang, Zhi-gang; Yu, Hong-mei
2012-01-01
The content of the elements C, H, O and N in Jinhua bergamot was analysed by using Vario III elemental analyser, the bergamot sample was scanned by using X-ray fluorescence spectrometer with PW2400 wavelength dispersion, and the content of the elements Mg, Al, P, S, Cl, K, Ca, Mn, Fe and Sr was analysed by using IQ+ analytical method. It turned out that the result is more ideal if the content of the elements C, H, O and N is processed as fix phase, and the analytical result is more ideal if, to prevent the sample skin from coming off, the sample is wrapped with mylar film with the film coefficient adjusted.
Elemental analysis of some Egyptian ores and industrial iron samples by neutron activation analysis
无
2001-01-01
Elemental analysis of iron ore samples and first industrial iron production prepared by the Egyptian Iron and Steel Company of Helwan near Cairo were determined by instrumental neutron activation analysis technique. Five samples from each kind were irradiated for a 48 hours at a thermal neutron flux of 4x1012 n/(cm2.s) in the first Egyptian research reactor ET-PP-1. Also the pneumatic irradiation rabbit system (PIRS) attached to the reactor in Inshass, was used to measure the elements of short-life time.The gamma-ray spectra were recorded by means of the hyper pure germanium detection system. The concentration percentage values of major, minor and trace elements are presented. The long and short lived isotopes were considered. A comparative study and a discussion on the elemental concentration values are given.
Sroo, A; Abdel-Basset, N; Abdel-Haleem, A S; Hassan, A M
2001-03-01
Elemental analysis of two iron ores and initial industrial iron production prepared by the Egyptian Iron and Steel Company of Helwan near Cairo were performed by the instrumental neutron activation analysis technique. Five samples of each type were irradiated for 48 h in a thermal neutron flux of 4 x 10(12) n/cm2 s in the first Egyptian research reactor ET-RR-1. Also, the Pneumatic Irradiation Rabbit System (PIRS), attached to the reactor ET-RR-1 in Inshass, was used to measure short-life elements. The gamma-ray spectra were obtained with a hyper pure germanium detection system. The concentration percentage values of major, minor and trace elements are presented. Implications of the elemental concentration values obtained are presented.
Sroor, A.; Abdel-Basset, N.; Abdel-Haleem, A.S.; Hassan, A.M
2001-03-01
Elemental analysis of two iron ores and initial industrial iron production prepared by the Egyptian Iron and Steel Company of Helwan near Cairo were performed by the instrumental neutron activation analysis technique. Five samples of each type were irradiated for 48 h in a thermal neutron flux of 4x10{sup 12} n/cm{sup 2} s in the first Egyptian research reactor ET-RR-1. Also, the Pneumatic Irradiation Rabbit System (PIRS), attached to the reactor ET-RR-1 in Inshass, was used to measure short-life elements. The {gamma}-ray spectra were obtained with a hyper pure germanium detection system. The concentration percentage values of major, minor and trace elements are presented. Implications of the elemental concentration values obtained are presented.
Elemental analysis of some Egyptian ores and industrial iron samples by neutron activation analysis.
Srror, A; Abdel-Basset, N; Abdel-Haleem, A S; Hassan, A M
2001-01-01
Elemental analysis of iron ore samples and first industrial iron production prepared by the Egyptian Iron and Steel Company of Helwan near Cairo were determined by instrumental neutron activation analysis technique. Five samples from each kind were irradiated for a 48 hours at a thermal neutron flux of 4 x 10(12) n/(cm2.s) in the first Egyptian research reactor ET-RR-1. Also the Pneumatic irradiation Rabbit system (PIRS) attached to the reactor in Inshass, was used to measure the elements of short-life time. The gamma-ray spectra were recorded by means of the hyper pure germanium detection system. The concentration percentage values of major, minor and trace elements are presented. The long and short lived isotopes were considered. A comparative study and a discussion on the elemental concentration values are given.
Elemental analysis of rain- and fresh water by neutron activation analysis
无
2001-01-01
Analysis of rain-and fresh water for trace constituents is a manda tory part of environmental monitoring. This text gives a survey of neutron activation analysis (NAA) within the framework of current environmental water research pro grammes, based on the practice developed in co-operation with the Dutch Energy Research Centre at Petten (ECN). While the procedures reported in literature cover about thirty five elements, our routine procedures of instrumental neutron activation analysis (INAA) is limited to ten to fifteen elements. The use of some dedicated ra diochemical separations (RNAA) adds another six, some of which are speciated as well. Current contributions of NAA to water analysis center on determination and speciation of anionic trace elements, notably Br, I, As. and Se, on the assay of some ultra traces like Ag, Au and Hg and on validation.
Multiscale Modeling of the Impact of Textile Fabrics Based on Hybrid Element Analysis
2010-05-19
Leighton RB, Sands M. The Feynman lectures on physics , definitive edition, vol. 1. Addison-Wesley Publishing Company; 2006. ISBN 0- 8053-9046-4. [21...model with distance away from the impact zone based on the multiscale nature of the fabric architecture and the physics of the impact event. Solid...nature of the fabric architecture and the physics of the impact event. Solid elements are used to discretize the yarns around the impact region
Elemental analysis of soil and hair sample by instrumental neutron activation analysis
Chung, Yong Sam; Quraishi, Shamshad Begum; Moon, Jong Hwa; Kim, Sun Ha; Baek, Sung Yeoil; Kang, Sang Hoon; Lim, Jong Myoung; Cho, Hyun Je; Kim, Young Jin
2004-03-01
Myanmar soil sample was analyzed by using the instrumental neutron activation analysis. The elemental concentrations in the sample, altogether 34 elements, Al As, Ba, Ce, Co, Cr, Cs, Eu, Fe, Ga, Gd, Hf, Ir, K, La, Lu, Mn, Na, Nd, Rb, Sb, Sc, Se, Sm, Th, Ti, V, Yb, Zn and Zr were determined. The concentration of 17 elements (Al, Au, Br, Ca, Cl, Cr, Cu, Co, Fe, Hg, K, Na, Mn, Mg, Sb, Se, Zn) in human hair samples were determined by INAA For quality control of analytical method, certified reference material was used.
Puso, M; Maker, B N; Ferencz, R M; Hallquist, J O
2000-03-24
This report provides the NIKE3D user's manual update summary for changes made from version 3.0.0 April 24, 1995 to version 3.3.6 March 24,2000. The updates are excerpted directly from the code printed output file (hence the Courier font and formatting), are presented in chronological order and delineated by NIKE3D version number. NIKE3D is a fully implicit three-dimensional finite element code for analyzing the finite strain static and dynamic response of inelastic solids, shells, and beams. Spatial discretization is achieved by the use of 8-node solid elements, 2-node truss and beam elements, and 4-node membrane and shell elements. Thirty constitutive models are available for representing a wide range of elastic, plastic, viscous, and thermally dependent material behavior. Contact-impact algorithms permit gaps, frictional sliding, and mesh discontinuities along material interfaces. Several nonlinear solution strategies are available, including Full-, Modified-, and Quasi-Newton methods. The resulting system of simultaneous linear equations is either solved iteratively by an element-by-element method, or directly by a direct factorization method.
ACCURACY ANALYSIS OF 12-PARAMETERRECTANGULAR PLATE ELEMENTS WITH GEOMETRIC SYMMETRY
SHI Dongyang; CHEN Shaochun
2000-01-01
In this paper, it is proved that the double set parameter rectangular plate elements with geometric symmetry possess a very special convergence property, i.e., the consistency error due to nonconformity is of order O(h2) which is one order higher than that of ACM element and rectangular generalized conforming element proposed by Y. Q.Long, although all these elements have the same asympotical rate of convergence O(h)in the energy norm. This particular property seems to be never seen before for other nonconforming rectangular plate elements.
A mixed finite element for the analysis of laminated plates
Putcha, N. S.; Reddy, J. N.
1983-01-01
A new mixed shear-flexible finite element based on the Hellinger-Reissner's variational principle is developed. The element is constructed using a mixed formulation of the shear deformation theory of laminated composite plates, and consists of three displacements, two shear rotations, and three moments as the independent degrees of freedom. The numerical convergence and accuracy characteristics of the element are investigated for bending of laminated anisotropic composite plates. The element is relatively simple to construct and has better accuracy and convergence features when compared to other conventional finite elements.
Barazzetti, L.; Banfi, F.; Brumana, R.; Gusmeroli, G.; Oreni, D.; Previtali, M.; Roncoroni, F.; Schiantarelli, G.
2015-02-01
This paper describes the use of BIM models derived from point clouds for structural simulation based on Finite Element Analysis (FEA). Although BIM interoperability has reached a significant level of maturity, the density of laser point clouds provides very detailed BIM models that cannot directly be used in FEA software. The rationalization of the BIM towards a new finite element model is not a simple reduction of the number of nodes. The interconnections between the different elements and their materials require a particular attention: BIM technology includes geometrical aspects and structural considerations that allow one to understand and replicate the constructive elements and their mutual interaction. The information must be accurately investigated to obtain a finite element model suitable for a complete and detailed structural analysis. The aim of this paper is to prove that a drastic reduction of the quality of the BIM model is not necessary. Geometric data encapsulated into dense point clouds can be taken into consideration also for finite element analysis.
Further finite element structural analysis of FAST Load Assembly
Frosi, Paolo, E-mail: paolo.frosi@enea.it [Associazione Euratom ENEA sulla Fusione, C.R. Frascati, Via E. Fermi 45, 00044 Frascati, Rome (Italy); Crescenzi, F.; Cucchiaro, A.; Roccella, S. [Associazione Euratom ENEA sulla Fusione, C.R. Frascati, Via E. Fermi 45, 00044 Frascati, Rome (Italy)
2013-10-15
The FAST (Fusion Advanced Study Torus) machine is a compact high magnetic field tokamak, that will allow to study in an integrated way the main operational issues relating to plasma-wall interaction, plasma operation and burning plasma physics in conditions relevant for ITER and DEMO. The present work deals with the structural analysis of the machine Load Assembly for a proposed new plasma scenario (10 MA – 8.5 T), aimed to increase the operational limits of the machine. A previous paper has dealt with an integrated set of finite element models (regarding a former reference scenario: 6.5 MA – 7.5 T) of the load assembly, including the Toroidal and Poloidal Field Coils and the supporting structure. This set of models has regarded the evaluation of magnetic field values, the evaluation of the electromagnetic forces and the temperatures in all the current-carrying conductors: these analysis have been a preparatory step for the evaluation of the stresses of the main structural components. The previous models have been analyzed further on and improved in some details, including the computation of the out-of-plane electromagnetic forces coming from the interaction between the poloidal magnetic field and the current flowing in the toroidal magnets. After this updating, the structural analysis has been executed, where all forces and temperatures, coming from the formerly mentioned most demanding scenario (10 MA – 8.5 T) and acting on the tokamak's main components, have been considered. The two sets of analysis regarding the reference scenario and the extreme one have been executed and a useful comparison has been carried on. The analyses were carried out by using the FEM code Ansys rel. 13.
Metal speciation of phosphorus derived from solid state spectroscopic analysis
Significant improvements have been made in the last decade towards understanding metal species associated with manure P using XANES and solid-state 31P NMR techniques. Both solid-state techniques are particularly sensitive to inorganic forms of P associated with metals in manure samples. In unamen...
Analysis of Dynamic Modeling Method Based on Boundary Element
Xu-Sheng Gan
2013-07-01
Full Text Available The aim of this study was to study an improved dynamic modeling method based on a Boundary Element Method (BEM. The dynamic model was composed of the elements such as the beam element, plate element, joint element, lumped mass and spring element by the BEM. An improved dynamic model of a machine structure was established based on plate-beam element system mainly. As a result, the dynamic characteristics of a machine structure were analyzed and the comparison of computational results and experimental’s showed the modeling method was effective. The analyses indicate that the introduced method inaugurates a good way for analyzing dynamic characteristics of a machine structure efficiently.
Wang, Ji; Sun, Qiang; Wu, Rongxing; Huang, Bin; Du, Jianke; Xiang, Wei
2015-01-01
The finite element analysis of high frequency vibrations of quartz crystal plates is a necessary process required in the design of quartz crystal resonators of precision types for applications in filters and sensors. The anisotropic materials and extremely high frequency in radiofrequency range of resonators determine that vibration frequency spectra are complicated with strong couplings of large number of different vibration modes representing deformations which do not appear in usual structural problems. For instance, the higher-order thickness-shear vibrations usually representing the sharp deformation of thin plates in the thickness direction, expecting the analysis is to be done with refined meshing schemes along the relatively small thickness and consequently the large plane area. To be able to represent the precise vibration mode shapes, a very large number of elements are needed in the finite element analysis with either the three-dimensional theory or the higher-order plate theory, although considera...
Finite element analysis of constrained total Condylar Knee Prosthesis
NONE
1998-07-13
Exactech, Inc., is a prosthetic joint manufacturer based in Gainesville, FL. The company set the goal of developing a highly effective prosthetic articulation, based on scientific principles, not trial and error. They developed an evolutionary design for a total knee arthroplasty system that promised improved performance. They performed static load tests in the laboratory with similar previous designs, but dynamic laboratory testing was both difficult to perform and prohibitively expensive for a small business to undertake. Laboratory testing also cannot measure stress levels in the interior of the prosthesis where failures are known to initiate. To fully optimize their designs for knee arthroplasty revisions, they needed range-of-motion stress/strain data at interior as well as exterior locations within the prosthesis. LLNL developed computer software (especially NIKE3D) specifically designed to perform stress/strain computations (finite element analysis) for complex geometries in large displacement/large deformation conditions. Additionally, LLNL had developed a high fidelity knee model for other analytical purposes. The analysis desired by Exactech could readily be performed using NIKE3D and a modified version of the high fidelity knee that contained the geometry of the condylar knee components. The LLNL high fidelity knee model was a finite element computer model which would not be transferred to Exactech during the course of this CRADA effort. The previously performed laboratory studies by Exactech were beneficial to LLNL in verifying the analytical capabilities of NIKE3D for human anatomical modeling. This, in turn, gave LLNL further entree to perform work-for-others in the prosthetics field. There were two purposes to the CRADA (1) To modify the LLNL High Fidelity Knee Model to accept the geometry of the Exactech Total Knee; and (2) To perform parametric studies of the possible design options in appropriate ranges of motion so that an optimum design could be
Comparative analysis of aerosols elemental distribution in some Romanian regions
Amemiya, Susumu; Masuda, Toshio; Popa-Simil, Liviu; Mateescu, Liviu
1996-04-01
The study's main aim is obtaining aerosols particulate elemental distribution and mapping it for some Romanian regions, in order to obtain preliminary information regarding the concentrations of aerosol particles and networking strategy versus local conditions. For this we used the mobile sampling strategy, but taking care on all local specific conditions and weather. In the summer of 1993, in July we took about 8 samples on a rather large territory of SE Romania which were analysed and mapped. The regions which showed an interesting behaviour or doubts such as Bucharest and Dobrogea were zoomed in near the same period of 1994, for comparing the new details with the global aspect previously obtained. An attempt was made to infer the minimum necessary number of stations in a future monitoring network. A mobile sampler was used, having tow polycarbonate filter posts of 8 and 0.4 μm. PIXE elemental analysis was performed on a 2.5 MV Van de Graaff accelerator, by using a proton beam. More than 15 elements were measured. Suggestive 2D and 3D representations were drawn, as well as histogram charts for the concentrations' distribution in the specific regions at the specified times. In spite of the poor samples from the qualitative point of view the experiment surprised us by the good coincidence (good agreement) with realities in terrain known by other means long time ago, and highlighted the power of PIXE methods in terms of money and time. Conclusions over the link between industry, traffic, vegetation, wether, surface waters, soil composition, power plant exhaust and so on, on the one hand, and surface concentration distribution, on the other, were drawn. But the method's weak points were also highlighted; these are weather dependencies (especially air masses movement and precipitation), local relief, microclimate and vegetation, and of course localisation of the sampling point versus the pollution sources and their regime. The paper contains a synthesis of the whole
Biomechanical study of tarsometatarsal joint fusion using finite element analysis.
Wang, Yan; Li, Zengyong; Zhang, Ming
2014-11-01
Complications of surgeries in foot and ankle bring patients with severe sufferings. Sufficient understanding of the internal biomechanical information such as stress distribution, contact pressure, and deformation is critical to estimate the effectiveness of surgical treatments and avoid complications. Foot and ankle is an intricate and synergetic system, and localized intervention may alter the functions to the adjacent components. The aim of this study was to estimate biomechanical effects of the TMT joint fusion using comprehensive finite element (FE) analysis. A foot and ankle model consists of 28 bones, 72 ligaments, and plantar fascia with soft tissues embracing all the segments. Kinematic information and ground reaction force during gait were obtained from motion analysis. Three gait instants namely the first peak, second peak and mid-stance were simulated in a normal foot and a foot with TMT joint fusion. It was found that contact pressure on plantar foot increased by 0.42%, 19% and 37%, respectively after TMT fusion compared with normal foot walking. Navico-cuneiform and fifth meta-cuboid joints sustained 27% and 40% increase in contact pressure at second peak, implying potential risk of joint problems such as arthritis. Von Mises stress in the second metatarsal bone increased by 22% at midstance, making it susceptible to stress fracture. This study provides biomechanical information for understanding the possible consequences of TMT joint fusion.
Neck incision planning for total laryngectomy: A finite element analysis.
Feng, Allen L; Clark, James H; Agrawal, Nishant; Moussa, Walied; Richmon, Jeremy D
2015-11-26
Post-operative complications can be attributed to technical aspects of surgery, yet no studies have investigated the mechanics behind commonly used incisions for total laryngopharyngectomies (TLP). This procedure, seen in head and neck cancer patients, necessitates free tissue transfer to construct a neo-pharynx, creating an inherently greater risk of complications. We sought to investigate the impact of neck incision location on these post-operative complications for TLP using finite element analysis (FEA). A nonlinear hyperelastic 2-D finite element model was used to evaluate the stress and strain along the incision line of two separate neck incision models commonly used for TLP: low-neck apron (LNA) incisions that incorporate the patient׳s tracheostoma and mid-neck apron (MNA) incisions that do not communicate with the tracheostoma. A constant displacement was applied to the incision to simulate normal neck extension experienced during the post-operative phase. Each neck incision was also modeled at varying strain energy densities to simulate various stages of wound healing. For a constant displacement of 40mm, the principal von Mises stress of the LNA incision varied between 5.87 and 6.41MPa, depending on the hyperelastic properties of the healing incision. This stress was concentrated at the junction of the incision and the fixed tracheostomal edge. The MNA model demonstrated a principal von Mises stress that varied between 0.558 and 0.711MPa and was concentrated along the midline of the neck incision. MNA incisions for TL patients result in principal von Mises stresses which are up to 11 times lower than those seen in LNA incisions. These results coincided with clinical observations from a concurrent study that showed a decrease in rate of wound dehiscence for patients undergoing TLP with an MNA incision.
Finite Element Analysis of Patella Alta: A Patellofemoral Instability Model
Duchman, Kyle R.; Grosland, Nicole M.; Bollier, Matthew J.
2017-01-01
Abstract Background: This study aims to provide biomechanical data on the effect of patella height in the setting of medial patellofemoral ligament (MPFL) reconstruction using finite element analysis. The study will also examine patellofemoral joint biomechanics using variable femoral insertion sites for MPFL reconstruction. Methods: A previously validated finite element knee model was modified to study patella alta and baja by translating the patella a given distance to achieve each patella height ratio. Additionally, the models were modified to study various femoral insertion sites of the MPFL (anatomic, anterior, proximal, and distal) for each patella height model, resulting in 32 unique scenarios available for investigation. Results: In the setting of patella alta, the patellofemoral contact area decreased, resulting in a subsequent increase in maximum patellofemoral contact pressures as compared to the scenarios with normal patellar height. Additionally, patella alta resulted in decreased lateral restraining forces in the native knee scenario as well as following MPFL reconstruction. Changing femoral insertion sites had a variable effect on patellofemoral contact pressures; however, distal and anterior femoral tunnel malpositioning in the setting of patella alta resulted in grossly elevated maximum patellofemoral contact pressures as compared to other scenarios. Conclusions: Patella alta after MPFL reconstruction results in decreased lateral restraining forces and patellofemoral contact area and increased maximum patellofemoral contact pressures. When the femoral MPFL tunnel is malpositioned anteriorly or distally on the femur, the maximum patellofemoral contact pressures increase with severity of patella alta. Clinical Relevance: When evaluating patients with patellofemoral instability, it is important to recognize patella alta as a potential aggravating factor. Failure to address patella alta in the setting of MPFL femoral tunnel malposition may result in
Bhardwaj, Rajneesh; Longtin, Jon P.; Attinger, Daniel
2010-01-01
The objective of this work is to investigate the coupling of fluid dynamics, heat transfer and mass transfer during the impact and evaporation of droplets on a heated solid substrate. A laser-based thermoreflectance method is used to measure the temperature at the solid-liquid interface, with a time and space resolution of 100 {\\mu}s and 20 {\\mu}m, respectively. Isopropanol droplets with micro- and nanoliter volumes are considered. A finite-element model is used to simulate the transient flui...
Dynamic Analysis of a Centrifugal Compressor by Finite Element Method%用有限元法分析离心压缩机的动力学特性
余光伟; 朱勤; 徐礼胜
2000-01-01
This paper mainly deals with dynamic analysis of rotor-bearing system in a centrifugal compressor. A finite element model of the rotor-bearing system has been developed. The considered factors of the model include the rotary inertia of solid elements, stiffness and damping of hydrodynamic bearing. In the calculating, ANSYS software was used. Both calculated and measured results are in good agreement.
Hosseini, Seyed Abolfaz [Dept. of Energy Engineering, Sharif University of Technology, Tehran (Iran, Islamic Republic of)
2017-02-15
The purpose of the present study is the presentation of the appropriate element and shape function in the solution of the neutron diffusion equation in two-dimensional (2D) geometries. To this end, the multigroup neutron diffusion equation is solved using the Galerkin finite element method in both rectangular and hexagonal reactor cores. The spatial discretization of the equation is performed using unstructured triangular and quadrilateral finite elements. Calculations are performed using both linear and quadratic approximations of shape function in the Galerkin finite element method, based on which results are compared. Using the power iteration method, the neutron flux distributions with the corresponding eigenvalue are obtained. The results are then validated against the valid results for IAEA-2D and BIBLIS-2D benchmark problems. To investigate the dependency of the results to the type and number of the elements, and shape function order, a sensitivity analysis of the calculations to the mentioned parameters is performed. It is shown that the triangular elements and second order of the shape function in each element give the best results in comparison to the other states.
Test and Analysis of Solid Rocket Motor Nozzle Ablative Materials
Clayton, J. Louie
2017-01-01
Asbestos free solid motor internal insulation samples were tested at the MSFC Hyperthermal Facility. Objectives of the test were to gather data for analog characterization of ablative and in-depth thermal performance of rubber materials subject to high enthalpy/pressure flow conditions. Tests were conducted over a range of convective heat fluxes for both inert and chemically reactive sub-sonic free stream gas flow. Instrumentation included use of total calorimeters, thermocouples, and a surface pyrometer for surface temperature measurement. Post-test sample forensics involved measurement of eroded depth, charred depth, total sample weight loss, and documentation of the general condition of the eroded profile. A complete Charring Material Ablator (CMA) style aero-thermal analysis was conducted for the test matrix and results compared to the measured data. In general, comparisons were possible for a number of the cases and the results show a limited predictive ability to model accurately both the ablative response and the in-depth temperature profiles. Lessons learned and modeling recommendations are made regarding future testing and modeling improvements that will increase understanding of the basic chemistry/physics associated with the complicated material ablation process of rubber materials.
Latif, Sk A; Oura, Y; Ebihara, M; Nakahara, H
2013-11-01
Prompt gamma-ray neutron activation analysis (PGNAA) using the internal mono-standard method was tested for its applicability to analyzing large solid samples including irregularly shaped meteorite samples. For evaluating the accuracy and precision of the method, large quantities of the Geological Survey of Japan standardized rock powders (JB-1a, JG-1a, and JP-1) were analyzed and 12 elements (B, Na, Mg, Al, Cl, K, Ca, Ti, Mn, Fe, Sm, and Gd) were determined by using Si as an internal standard element. Analytical results were mostly in agreement with literature values within 10 %. The precision of the method was also shown to be within 10 % (1σ) for most of these elements. The analytical procedure was then applied to four stony meteorites (Allende, Kimble County, Leedey, Lake Labyrinth) and four iron meteorites (Canyon Diablo, Toluca (Mexico), Toluca (Xiquipilco), Squaw Creek) consisting of large chunks or single slabs. For stony meteorites, major elements (Mg, Al, Si, S, Ca, and Ni), minor elements (Na and Mn) and trace element (B, Cl, K, Ti, Co, and Sm) were determined with adequate accuracy. For iron meteorites, results for the Co and Ni mass fractions determined are all consistent with corresponding literature values. After the analysis, it was confirmed that the residual radioactivity remaining in the sample after PGNAA was very low and decreased down to the background level. This study shows that PGNAA with the internal mono-standard method is highly practical for determining the elemental composition of large, irregularly shaped solid samples including meteorites.
Modeling and validation of a 3D premolar for finite element analysis
Letícia Brandão DURAND
Full Text Available Abstract Introduction The development and validation of mathematical models is an important step of the methodology of finite element studies. Objective This study aims to describe the development and validation of a three-dimensional numerical model of a maxillary premolar for finite element analysis. Material and method The 3D model was based on standardized photographs of sequential slices of an intact premolar and generated with the use of SolidWorks Software (Dassault, France. In order to validate the model, compression and numerical tests were performed. The load versus displacement graphs of both tests were visually compared, the percentage of error calculated and homogeneity of regression coefficients tested. Result An accurate 3D model was developed and validated since the graphs were visually similar, the percentage error was within acceptable limits, and the straight lines were considered parallel. Conclusion The modeling procedures and validation described allows the development of accurate 3D dental models with biomechanical behavior similar to natural teeth. The methods may be applied in development and validation of new models and computer-aided simulations using FEM.
MA Linwei; MO Jianhua
2008-01-01
Single-point incremental forming (SPIF) is an innovational sheet metal forming method without dedicated dies, which belongs to rapid prototyping technology. In generalizing the SPIF of sheet metal, the deformation analysis on forming process becomes an important and useful method for the planning of shell products, the choice of material, the design of the forming process and the planning of the forming tool. Using solid brick elements, the finite element method(FEM) model of truncated pyramid was established. Based on the theory of anisotropy and assumed strain formulation, the SPIF processes with different parameters were simulated. The resulted comparison between the simulations and the experiments shows that the FEM model is feasible and effective. Then, according to the simulated forming process, the deformation pattern of SPIF can be summarized as the combination of plane-stretching deformation and bending deformation. And the study about the process parameters' impact on deformation shows that the process parameter of interlayer spacing is a dominant factor on the deformation. Decreasing interlayer spacing, the strain of one step decreases and the formability of blank will be improved. With bigger interlayer spacing, the plastic deformation zone increases and the forming force will be bigger.
He Ping
2004-01-01
For electrothermal-film heating elements for ceramics, the quantitative expression of the relation between the contents of multicomponent semiconductor dope and rare-earth element additive through the multivariate statistical regression analysis was presented, and the optimum control index of the multicomponent semiconductor dope and the rareearth element for the maximum life was also determined. The research shows that the life value ranging from 15 to 20 thousand hours can be ensured only if the evaluation grade of metal oxide dope in the compounding formula is controlled between grades 0.5 to 1.2. The relation of the content of multicomponent rare-earth element dope and the life index of electrothermal-film heating material for ceramics was determined theoretically.
Analysis of 3-D Frictional Contact Mechanics Problems by a Boundary Element Method
KEUM Bangyong; LIU Yijun
2005-01-01
The development of two boundary element algorithms for solving 3-D, frictional, and linear elastostatic contact problems is reported in this paper. The algorithms employ nonconforming discretizations for solving 3-D boundary element models, which provide much needed flexibility in the boundary element modeling for 3-D contact problems. These algorithms are implemented in a new 3-D boundary element code and verified using several examples. For the numerical examples studied, the results using the new boundary element algorithms match very well with the results using a commercial finite element code, and clearly demonstrate the feasibility of the new boundary element approach for 3-D contact analysis.
Ramon Alvarez-Rodriguez; Carmen Clemente-Jul; Juan A. Martin-Rubi [Technical University of Madrid (UPM), Madrid (Spain). Mining School
2007-09-15
In this research on the solid products of the Elcogas IGCC plant (Puertollano, Spain) the influence of the two fuels, coal and pet coke, on the composition of the fly ashes and slag is demonstrated and how the majority of the elements are provided by the coal and only some as V, Ni and Mo are provided by the pet coke. The different nature of slag and fly ashes is highlighted and how the different elements are distributed between them that in general follow the indications of the mathematical models. The passage of the elements into gaseous phase is calculated. The fly ashes are some products of very fine granulometry that present problems of solubilization of a series of elements and therefore of deposition. Their inertization has been investigated by calcination at 1000{sup o}C and with additives. Some good results have been obtained. 20 refs., 14 figs., 4 tabs.
Benner, R.; Hatcher, P.G.; Hedges, J.I.
1990-01-01
Changes in the chemical composition of mangrove (Rhizophora mangle) leaves during decomposition in tropical estuarine waters were characterized using solid-state 13C nuclear magnetic resonance (NMR) and elemental (CHNO) analysis. Carbohydrates were the most abundant components of the leaves accounting for about 50 wt% of senescent tissues. Tannins were estimated to account for about 20 wt% of leaf tissues, and lipid components, cutin, and possibly other aliphatic biopolymers in leaf cuticles accounted for about 15 wt%. Carbohydrates were generally less resistant to decomposition than the other constituents and decreased in relative concentration during decomposition. Tannins were of intermediate resistance to decomposition and remained in fairly constant proportion during decomposition. Paraffinic components were very resistant to decomposition and increased in relative concentration as decomposition progressed. Lignin was a minor component of all leaf tissues. Standard methods for the colorimetric determination of tannins (Folin-Dennis reagent) and the gravimetric determination of lignin (Klason lignin) were highly inaccurate when applied to mangrove leaves. The N content of the leaves was particularly dynamic with values ranging from 1.27 wt% in green leaves to 0.65 wt% in senescent yellow leaves attached to trees. During decomposition in the water the N content initially decreased to 0.51 wt% due to leaching, but values steadily increased thereafter to 1.07 wt% in the most degraded leaf samples. The absolute mass of N in the leaves increased during decomposition indicating that N immobilization was occurring as decomposition progressed. ?? 1990.
Finite element method for thermal analysis of concentrating solar receivers
Shtrakov, Stanko; Stoilov, Anton
2006-01-01
Application of finite element method and heat conductivity transfer model for calculation of temperature distribution in receiver for dish-Stirling concentrating solar system is described. The method yields discretized equations that are entirely local to the elements and provides complete geometric flexibility. A computer program solving the finite element method problem is created and great number of numerical experiments is carried out. Illustrative numerical results are given for an array...
Elemental analysis using a handheld X-Ray fluorescence spectrometer
Groover, Krishangi D.; Izbicki, John
2016-06-24
The U.S. Geological Survey is collecting geologic samples from local stream channels, aquifer materials, and rock outcrops for studies of trace elements in the Mojave Desert, southern California. These samples are collected because geologic materials can release a variety of elements to the environment when exposed to water. The samples are to be analyzed with a handheld X-ray fluorescence (XRF) spectrometer to determine the concentrations of up to 27 elements, including chromium.
Bulut, Volkan Numan [Department of Chemistry, Giresun Faculty of Arts and Sciences, Karadeniz Technical University, 28049 Giresun (Turkey); Gundogdu, Ali [Department of Chemistry, Faculty of Arts and Sciences, Karadeniz Technical University, 61080 Trabzon (Turkey); Duran, Celal [Department of Chemistry, Faculty of Arts and Sciences, Karadeniz Technical University, 61080 Trabzon (Turkey); Senturk, Hasan Basri [Department of Chemistry, Faculty of Arts and Sciences, Karadeniz Technical University, 61080 Trabzon (Turkey); Soylak, Mustafa [Department of Chemistry, Faculty of Arts and Sciences, Erciyes University, 38039 Kayseri (Turkey)]. E-mail: msoylak@gmail.com; Elci, Latif [Department of Chemistry, Faculty of Arts and Sciences, Pamukkale University, 20020 Denizli (Turkey); Tufekci, Mehmet [Department of Chemistry, Faculty of Arts and Sciences, Karadeniz Technical University, 61080 Trabzon (Turkey)
2007-07-19
A method for the preconcentration of some transition elements at trace level was proposed using a column filled with Amberlite XAD-2000 resin. Metal ions were adsorbed on XAD-2000 as their diethyldithiocarbamate chelates, then analytes retained on the resin were eluted by 1 mol L{sup -1} nitric acid in acetone and determined by flame atomic absorption spectrometry (FAAS). The influences of some analytical parameters including pH of sample solution, ligand amount, the type, concentration and volume of elution solution, flow rates of the sample and eluent solutions, adsorption capacity of the resin and sample volume on the preconcentration efficiency have been investigated. The influences of some matrix elements were also examined. The detection limit (N = 20, 3 sigma) for Mn(II), Fe(II), Co(II), Cu(II), Cd(II), Zn(II), Pb(II) and Ni(II) were found as 0.20, 0.35, 0.25, 0.20, 0.20, 0.15, 0.45 and 0.25 {mu}g L{sup -1}, respectively. The validation of the procedure was carried out by analysis of certified reference materials. The proposed method was applied to natural waters and kale vegetable (Brassica oleracea var. acephala)
Bulut, Volkan Numan; Gundogdu, Ali; Duran, Celal; Senturk, Hasan Basri; Soylak, Mustafa; Elci, Latif; Tufekci, Mehmet
2007-07-19
A method for the preconcentration of some transition elements at trace level was proposed using a column filled with Amberlite XAD-2000 resin. Metal ions were adsorbed on XAD-2000 as their diethyldithiocarbamate chelates, then analytes retained on the resin were eluted by 1 mol L(-1) nitric acid in acetone and determined by flame atomic absorption spectrometry (FAAS). The influences of some analytical parameters including pH of sample solution, ligand amount, the type, concentration and volume of elution solution, flow rates of the sample and eluent solutions, adsorption capacity of the resin and sample volume on the preconcentration efficiency have been investigated. The influences of some matrix elements were also examined. The detection limit (N=20, 3 sigma) for Mn(II), Fe(II), Co(II), Cu(II), Cd(II), Zn(II), Pb(II) and Ni(II) were found as 0.20, 0.35, 0.25, 0.20, 0.20, 0.15, 0.45 and 0.25 microg L(-1), respectively. The validation of the procedure was carried out by analysis of certified reference materials. The proposed method was applied to natural waters and kale vegetable (Brassica oleracea var. acephala).
Finite element approach for transient analysis of multibody systems
Wu, Shih-Chin; Chang, Che-Wei; Housner, Jerrold M.
1992-01-01
A three-dimensional, finite element based formulation for the transient dynamics of constrained multibody systems with trusslike configurations is presented. A convected coordinate system is used to define the rigid-body motion of individual elements in the system. Deformation of each element is defined relative to its convected coordinate system. The formulation is oriented toward joint-dominated structures. Through a series of sequential transformations, the joint degree of freedom is built into the equations of motion of the element to reduce geometric constraints. Based on the derivation, a general-purpose code has been developed. Two examples are presented to illustrate the application of the code.
Ablative Thermal Response Analysis Using the Finite Element Method
Dec John A.; Braun, Robert D.
2009-01-01
A review of the classic techniques used to solve ablative thermal response problems is presented. The advantages and disadvantages of both the finite element and finite difference methods are described. As a first step in developing a three dimensional finite element based ablative thermal response capability, a one dimensional computer tool has been developed. The finite element method is used to discretize the governing differential equations and Galerkin's method of weighted residuals is used to derive the element equations. A code to code comparison between the current 1-D tool and the 1-D Fully Implicit Ablation and Thermal Response Program (FIAT) has been performed.
Stress and Deformation Analysis in Base Isolation Elements Using the Finite Element Method
Claudiu Iavornic
2011-01-01
Full Text Available In Modern tools as Finite Element Method can be used to study the behavior of elastomeric isolation systems. The simulation results obtained in this way provide a large series of data about the behavior of elastomeric isolation bearings under different types of loads and help in taking right decisions regarding geometrical optimizations needed for improve such kind of devices.
Elemental analysis of samples of rare earths; Analisis elemental de muestras de tierras raras
Lopez M, J.; Ramirez T, J.J.; Sandoval J, R.A.; Aspiazu F, J.; Villasenor S, P. [ININ, 52045 Ocoyoacac, Estado de Mexico (Mexico); Lugo L, M.F. [IFUNAM, 04500 Mexico D.F. (Mexico)
2003-07-01
Applying the PIXE technique (Particle Induced X-Ray Emission) it was analyzed the purity of the samples that will be used to measure the production section of X rays with Li and B beams. It is not necessary to determine the concentrations of the pollutant elements. (Author)
Sandis irradiator for dried sewage solids. Final safety analysis report
Morris, M.
1980-07-01
Analyses of the hazards associated with the operation of the Sandia irradiator for dried sewage solids, as well as methods and design considerations to minimize these hazards, are presented in accordance with DOE directives.
Testing and analysis of a modernized freight wagon's elements flammability
Płaczek, M.; Wróbel, A.; Baier, A.
2016-08-01
Paper concerns an issue of freight wagon modernization using composite materials. The goal of the project is to elongate the period between repairs (by better corrosion protection) and improve conditions of exploitation of modernized freight wagons (for example easier unloading during winter conditions - no freezes of the charge to the freight wagon body shell). Application of the composite panels to the freight wagon's body shell was proposed as the solution that can solve mentioned problems. The composite panels composed of fiberglass and epoxy resin were proposed. They will be mounted on the body shell using rivet nuts. What is more the body shell of the modernized freight wagon will be painted using an anti-corrosion agent. In this paper the analysis of a flammability of the proposed composition (the composite plate made of fiberglass and epoxy resin mounted to the steel sheet with additional anticorrosion agent) is presented. In the paper results of laboratory tests conducted according to international standards are presented. A series of samples of elements of modernized freight wagons was tested using the created laboratory stand. Obtained results were averaged and the proposed material was assigned to the one of the class of materials for their combustibility.
Finite Element Modeling of scattered electromagnetic waves for stroke analysis.
Priyadarshini, N; Rajkumar, E R
2013-01-01
Stroke has become one of the leading causes of mortality worldwide and about 800 in every 100,000 people suffer from stroke each year. The occurrence of stroke is ranked third among the causes of acute death and first among the causes for neurological dysfunction. Currently, Neurological examinations followed by medical imaging with CT, MRI or Angiography are used to provide better identification of the location and the type of the stroke, however they are neither fast, cost-effective nor portable. Microwave technology has emerged to complement these modalities to diagnose stroke as it is sensitive to the differences between the distinct dielectric properties of the brain tissues and blood. This paper investigates the possibility of diagnosing the type of stroke using Finite Element Analysis (FEA). The object of interest is a simulated head phantom with stroke, created with its specifying material characteristics like electrical conductivity and relative permittivity. The phantom is then placed in an electromagnetic field generated by a dipole antenna radiating at 1 GHz. The FEM forward model solver computes the scattered electromagnetic field by finding the solution for the Maxwell's wave equation in the head volume. Subsequently the inverse scattering problem is solved using the Contrast Source Inversion (CSI) method to reconstruct the dielectric profile of the head phantom.
Solar Electric Generating System II finite element analysis
Dohner, J.L.; Anderson, J.R.
1994-04-01
On June 2, 1992, Landers` earthquake struck the Solar Electric Generating System II, located in Daggett, California. The 30 megawatt power station, operated by the Daggett Leasing Corporation (DLC), suffered substantial damage due to structural failures in the solar farm. These failures consisted of the separation of sliding joints supporting a distribution of parabolic glass mirrors. At separation, the mirrors fell to the ground and broke. It was the desire of the DLC and the Solar Thermal Design Assistance Center (STDAC) of Sandia National Laboratories (SNL) and to redesign these joints so that, in the event of future quakes, costly breakage will be avoided. To accomplish this task, drawings of collector components were developed by the STDAC, from which a detailed finite element computer model of a solar collector was produced. This nonlinear dynamic model, which consisted of over 8,560 degrees of freedom, underwent model reduction to form a low order nonlinear dynamic model containing only 40 degrees of freedom. This model was then used as a design tool to estimate joint dynamics. Using this design tool, joint configurations were modified, and an acceptable joint redesign determined. The results of this analysis showed that the implementation of metal stops welded to support shafts for the purpose of preventing joint separation is a suitable joint redesign. Moreover, it was found that, for quakes of Landers` magnitude, mirror breakage due to enhanced vibration in the trough assembly is unlikely.
Endovascular nonthermal irreversible electroporation: a finite element analysis.
Maor, Elad; Rubinsky, Boris
2010-03-01
Tissue ablation finds an increasing use in modern medicine. Nonthermal irreversible electroporation (NTIRE) is a biophysical phenomenon and an emerging novel tissue ablation modality, in which electric fields are applied in a pulsed mode to produce nanoscale defects to the cell membrane phospholipid bilayer, in such a way that Joule heating is minimized and thermal damage to other molecules in the treated volume is reduced while the cells die. Here we present a two-dimensional transient finite element model to simulate the electric field and thermal damage to the arterial wall due to an endovascular NTIRE novel device. The electric field was used to calculate the Joule heating effect, and a transient solution of the temperature is presented using the Pennes bioheat equation. This is followed by a kinetic model of the thermal damage based on the Arrhenius formulation and calculation of the Henriques and Moritz thermal damage integral. The analysis shows that the endovascular application of 90, 100 mus pulses with a potential difference of 600 V can induce electric fields of 1000 V/cm and above across the entire arterial wall, which are sufficient for irreversible electroporation. The temperature in the arterial wall reached a maximum of 66.7 degrees C with a pulse frequency of 4 Hz. Thermal damage integral showed that this protocol will thermally damage less than 2% of the molecules around the electrodes. In conclusion, endovascular NTIRE is possible. Our study sets the theoretical basis for further preclinical and clinical trials with endovascular NTIRE.
Utilizing video animation to present FEA (Finite Element Analysis) results
Hayer, L.K.; Vossler, J.J. III.
1990-01-01
Finite element Analysis (FEA) technique are used to analyze forming, rolling, extrusion, and other continuous manufacturing processes to produce solutions at discrete points in time. These solutions are then displayed using a graphical post-processor. The post-processor displays one plot at a time making it difficult to follow events over the entire process. A means of linking these images that occur at discrete points in time and displaying them in a continuous fashion would aid in comprehending the significance of dynamic or time dependent events that evolve during the processes. Video recording of the graphics provides a means to link the graphical ouput at each discrete point in time and project the results in a continuous fashion upon playback. This presentation outlines the video hardware, the modifications to the pre- and post-processing software, and the process used to make video animation recording of FEA results. Several examples will be shown: Hydroforming of a Spherical Aluminum Shell'' and Three-Stage Forging.'' 5 refs., 7 figs.
FINITE ELEMENT ANALYSIS FOR OPTIMIZING ANTENNA FOR MICROWAVE COAGULATION THERAPY
MARWAHA S.
2012-08-01
Full Text Available Microwave coagulation therapy (MCT is emerging as an attractive modality for thermal therapy of soft tissues targeted in short periods of time, making it particularly suitable for ablation of hepatic and other tumors. In this field of microwave coagulation therapy, the use of minimally invasive antenna is recognized as a very promising technique for the treatment of small tumors because a very thin antenna can be easily inserted inside the body and precisely localized using the advanced 3D imaging techniques and surgical robots. The authors investigated the microwave coaxial antenna operating at 2.45 GHz by varying the slots size for the removal of liver tumor. The analysis was done using 2D finite element modeling. By several optimization steps the antenna is simulated and optimized by comparing the values of specific absorption rate (SAR, mesh statistics and temperature distributions in tissue generated by the antenna with the variations of dimensions of slot from 1 mm to 1.7 mm.
Finite element analysis of heel pad with insoles.
Luo, Gangming; Houston, Vern L; Garbarini, Mary Anne; Beattie, Aaron C; Thongpop, Chaiya
2011-05-17
To design optimal insoles for reduction of pedal tissue trauma, experimental measurements and computational analyses were performed. To characterize the mechanical properties of the tissues, indentation tests were performed. Pedal tissue geometry and morphology were obtained from magnetic resonance scan of the subject's foot. Axisymmetrical finite element models of the heel of the foot were created with 1/4 of body weight load applied. The stress, strain and strain energy density (SED) fields produced in the pedal tissues were computed. The effects of various insole designs and materials on the resulting stress, strain, and SED in the soft pedal tissues were analyzed. The results showed: (a) Flat insoles made of soft material provide some reductions in the maximum stress, strain and SED produced in the pedal tissues. These maximum values were computed near the calcaneus. (b) Flat insoles, with conical/cylindrical reliefs, provided more reductions in these maximum values than without reliefs. (c) Custom insoles, contoured to match the pedal geometry provide most reductions in the maximum stress, strain and SED. Also note, the maximum stress, strain and SED computed near the calcaneus were found to be about 10 times the corresponding peak values computed on the skin surface. Based on the FEA analysis, it can be concluded that changing insole design and using different material can significantly redistribute the stress/strain inside the heel pad as well as on the skin surface.
[Application of finite element analysis in Chinese cervical manipulation biomechanics].
Wang, Huihao; Chen, Bo; Zhan, Hongsheng; Wang, Huihao; Chen, Bo; Zhan, Hongsheng
2013-10-01
Clinical advantages of Chinese spinal manipulation therapy (CSMT) were recognized for spinal chronic lesions of soft tissues and bones, such as cervical spondylosis, etc. However, the security of CSMT and the hypotheses of practice mechanisms were questioned for lacking of the relevant basic researches. Researches have proved that these methods could be used to observe the dynamic effects of spine with application of finite element analysis (FEA) computer technology. Combining with other biomechanical experimental methods and applying advanced FEA technology for mechanical problems of CSMT, we may not only find the mechanisms of action and provide theoretical supports for the traditional Chinese therapy, but also standardize the key techniques and optimize the treatment options improving clinical outcomes, and even promote spreading of CSMT. Computer models are ideally suited for studying phenomena that cannot be satisfactorily investigated with other models. However, computer models of CSMT practice remain to be further refined. The results which had been acquired so far not only verified some of the traditional points of view, but also revised and specified some perspectives of the past. This paper intends to review FEA studies with Chinese cervical manipulation therapy (CCMT) for cervical spinal chronic lesions of soft tissues and bones, involving different effects for cervical spine joints (pulling/traction and thrusting) with practice techniques and cervical spine soft tissues (including vessels and its hemodynamics, muscles and fasciae, etc).
Parallel Finite Element Domain Decomposition for Structural/Acoustic Analysis
Nguyen, Duc T.; Tungkahotara, Siroj; Watson, Willie R.; Rajan, Subramaniam D.
2005-01-01
A domain decomposition (DD) formulation for solving sparse linear systems of equations resulting from finite element analysis is presented. The formulation incorporates mixed direct and iterative equation solving strategics and other novel algorithmic ideas that are optimized to take advantage of sparsity and exploit modern computer architecture, such as memory and parallel computing. The most time consuming part of the formulation is identified and the critical roles of direct sparse and iterative solvers within the framework of the formulation are discussed. Experiments on several computer platforms using several complex test matrices are conducted using software based on the formulation. Small-scale structural examples are used to validate thc steps in the formulation and large-scale (l,000,000+ unknowns) duct acoustic examples are used to evaluate the ORIGIN 2000 processors, and a duster of 6 PCs (running under the Windows environment). Statistics show that the formulation is efficient in both sequential and parallel computing environmental and that the formulation is significantly faster and consumes less memory than that based on one of the best available commercialized parallel sparse solvers.
Rapid Prototyping Integrated With Nondestructive Evaluation and Finite Element Analysis
Abdul-Aziz, Ali; Baaklini, George Y.
2001-01-01
Most reverse engineering approaches involve imaging or digitizing an object then creating a computerized reconstruction that can be integrated, in three dimensions, into a particular design environment. Rapid prototyping (RP) refers to the practical ability to build high-quality physical prototypes directly from computer aided design (CAD) files. Using rapid prototyping, full-scale models or patterns can be built using a variety of materials in a fraction of the time required by more traditional prototyping techniques (refs. 1 and 2). Many software packages have been developed and are being designed to tackle the reverse engineering and rapid prototyping issues just mentioned. For example, image processing and three-dimensional reconstruction visualization software such as Velocity2 (ref. 3) are being used to carry out the construction process of three-dimensional volume models and the subsequent generation of a stereolithography file that is suitable for CAD applications. Producing three-dimensional models of objects from computed tomography (CT) scans is becoming a valuable nondestructive evaluation methodology (ref. 4). Real components can be rendered and subjected to temperature and stress tests using structural engineering software codes. For this to be achieved, accurate high-resolution images have to be obtained via CT scans and then processed, converted into a traditional file format, and translated into finite element models. Prototyping a three-dimensional volume of a composite structure by reading in a series of two-dimensional images generated via CT and by using and integrating commercial software (e.g. Velocity2, MSC/PATRAN (ref. 5), and Hypermesh (ref. 6)) is being applied successfully at the NASA Glenn Research Center. The building process from structural modeling to the analysis level is outlined in reference 7. Subsequently, a stress analysis of a composite cooling panel under combined thermomechanical loading conditions was performed to validate
Mirjankar, Nikhil S; Fraga, Carlos G; Carman, April J; Moran, James J
2016-02-02
Chemical attribution signatures (CAS) for chemical threat agents (CTAs), such as cyanides, are being investigated to provide an evidentiary link between CTAs and specific sources to support criminal investigations and prosecutions. Herein, stocks of KCN and NaCN were analyzed for trace anions by high performance ion chromatography (HPIC), carbon stable isotope ratio (δ(13)C) by isotope ratio mass spectrometry (IRMS), and trace elements by inductively coupled plasma optical emission spectroscopy (ICP-OES). The collected analytical data were evaluated using hierarchical cluster analysis (HCA), Fisher-ratio (F-ratio), interval partial least-squares (iPLS), genetic algorithm-based partial least-squares (GAPLS), partial least-squares discriminant analysis (PLSDA), K nearest neighbors (KNN), and support vector machines discriminant analysis (SVMDA). HCA of anion impurity profiles from multiple cyanide stocks from six reported countries of origin resulted in cyanide samples clustering into three groups, independent of the associated alkali metal (K or Na). The three groups were independently corroborated by HCA of cyanide elemental profiles and corresponded to countries each having one known solid cyanide factory: Czech Republic, Germany, and United States. Carbon stable isotope measurements resulted in two clusters: Germany and United States (the single Czech stock grouped with United States stocks). Classification errors for two validation studies using anion impurity profiles collected over five years on different instruments were as low as zero for KNN and SVMDA, demonstrating the excellent reliability associated with using anion impurities for matching a cyanide sample to its factory using our current cyanide stocks. Variable selection methods reduced errors for those classification methods having errors greater than zero; iPLS-forward selection and F-ratio typically provided the lowest errors. Finally, using anion profiles to classify cyanides to a specific stock
THE PRACTICAL ANALYSIS OF FINITE ELEMENTS METHOD ERRORS
Natalia Bakhova
2011-03-01
Full Text Available Abstract. The most important in the practical plan questions of reliable estimations of finite elementsmethod errors are considered. Definition rules of necessary calculations accuracy are developed. Methodsand ways of the calculations allowing receiving at economical expenditures of computing work the best finalresults are offered.Keywords: error, given the accuracy, finite element method, lagrangian and hermitian elements.
Axisymmetric nonconforming element method and its convergence analysis
陈万吉; 高岩
1997-01-01
By virtue of the weighted Sobolev space theory, three convergence tests of the axisymmetric non-conforming element method are established. They consist of the generalized patch test, the F-E-M test and a test which could be used conveniently, called the strong patch test (SPT). In the light of SPT, a class of axisymmetric nonconforming elements is established.
Trace element analysis in silicon by accelerator SIMS
Ender, R.M.; Suter, M. [Eidgenoessische Technische Hochschule, Zurich (Switzerland); Doebeli, M.; Synal, H.A. [Paul Scherrer Inst. (PSI), Villigen (Switzerland)
1997-09-01
The accelerator SIMS technique has been applied to Si samples implanted with different elements. It has been shown that concentrations of several trace elements can be analysed down to about 1 ppb in depth profiling mode. (author) 2 figs., 1 ref.
Efficient Finite Element Methods for Transient Analysis of Shells.
1985-04-01
Triangular Shell Element with Improved Membrane Interpolation," Communications in Applied Numerical Methods , in press 1985. Results of this work were...in Applied Numerical Methods , to appear. G.R. Cowper, G.M. Lindberg and M.D. Olson (1970), "A Shallow Shell Finite Element of Triangular Shape," Int. J
Optimal fixation of acute scaphoid fractures: finite element analysis.
Luria, Shai; Hoch, Sarah; Liebergall, Meir; Mosheiff, Ram; Peleg, Eran
2010-08-01
The hypothesis of this study was that more stable fixation of acute scaphoid fractures may be achieved by a screw placed perpendicular to the fracture plane than along the long axis of the scaphoid, as previously suggested. We examined this assumption on different fracture patterns using a finite element analysis model. A computed tomography scan of an intact scaphoid of a young man provided the data set for all fracture models. We used semiautomatic segmentation to create 3-dimensional computer models of the 3 simple fracture configurations: oblique, transverse waist, and proximal fractures, according to the Herbert classification. Each fracture type was analyzed, using finite elements, for its biomechanical response to 2 types of virtual fixation: a screw placed either perpendicular to the fracture plane or centrally along the long axis of the scaphoid. We measured motion at the fracture plane (in millimeters) and strain in the screw threads (in millipascals). Considerably less motion was measured at the fracture plane with the perpendicular screw compared with the long axis screw, especially in the oblique-type fractures: (1) Herbert-type B1 oblique fracture mean motion of 0.05 mm (+/-0.03) for the perpendicular screw versus 0.28 mm (+/-0.05) for the long axis screw; (2) B2 transverse waist fracture mean motion of 0.06 mm (+/-0.03) for the perpendicular screw versus 0.18 mm (+/-0.06) for the long axis screw; and (3) B3 proximal fracture mean motion of 0.07 mm (+/-0.01) for the perpendicular screw versus 0.28 mm (+/-0.011) for the long axis screw. Higher strains were measured on the screw placed perpendicular to the fracture. According to this model, higher fixation stability is achieved when the scaphoid is fixated perpendicular to the fracture. In transverse waist fractures, a centrally placed screw will also be perpendicular to the fracture, which explains the results of previous models. Copyright 2010. Published by Elsevier Inc.
Analysis of Content of Selected Critical Elements in Fly Ash
Makowska Dorota
2016-03-01
Full Text Available Pursuant to the new mineral policy of the European Union, searching for new sources of raw materials is required. Coal fly ash has long been considered as a potential source of a number of critical elements. Therefore, it is important to monitor the contents of the critical elements in fly ash from coal combustion. The paper presents the results of examinations of the contents of selected elements, i.e. beryllium, cobalt, chromium and germanium in fly ash from Polish power plants. The results of the conducted investigations indicate that the examined ash samples from bituminous coal combustion cannot be treated as a potential source of the analysed critical elements. The content of these elements in ash, though slightly higher than their average content in the sedimentary rocks, is, however, not high enough to make their recovery technologically and economically justified at this moment.
Comparative Analysis of Households Solid Waste Management in Rural and Urban Ghana
Boateng, Simon; Amoako, Prince; Appiah, Divine Odame; Poku, Adjoa Afriyie; Garsonu, Emmanuel Kofi
2016-01-01
The comparative analysis of solid waste management between rural and urban Ghana is largely lacking. This study investigated the solid waste situation and the organisation of solid waste management in both urban and rural settings from the perspective of households. The study employed cross-sectional survey covering both rural and urban districts in the Ashanti and Greater Accra Regions of Ghana. The study systematically sampled houses from which 400 households and respondents were randomly s...
Comparative Analysis of Households Solid Waste Management in Rural and Urban Ghana
Simon Boateng; Prince Amoako; Divine Odame Appiah; Adjoa Afriyie Poku; Emmanuel Kofi Garsonu
2016-01-01
The comparative analysis of solid waste management between rural and urban Ghana is largely lacking. This study investigated the solid waste situation and the organisation of solid waste management in both urban and rural settings from the perspective of households. The study employed cross-sectional survey covering both rural and urban districts in the Ashanti and Greater Accra Regions of Ghana. The study systematically sampled houses from which 400 households and respondents were randomly s...
PHYSICAL MODEL FOR THE ENGINEERING ANALYSIS OF THE THERMOELASTICLTY OF SOLID BODIES
无
2000-01-01
The thermal behaviour of the solids under elastic deformations is analysed in order to obtain a model which combines the molecular dynamics results with the global thermal behaviour of the solids under elastic t ransformations.The result obtained consists of the introduction of the thermal behaviour in the ParrinelloRahman model,obtaining the thermal molecular dynamic model useful in the analysis of the thermoelastic behaviour of solids.