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Sample records for abaqus thermomechanics code

  1. Enhancing the ABAQUS Thermomechanics Code to Simulate Steady and Transient Fuel Rod Behavior

    R. L. Williamson; D. A. Knoll

    2009-09-01

    A powerful multidimensional fuels performance capability, applicable to both steady and transient fuel behavior, is developed based on enhancements to the commercially available ABAQUS general-purpose thermomechanics code. Enhanced capabilities are described, including: UO2 temperature and burnup dependent thermal properties, solid and gaseous fission product swelling, fuel densification, fission gas release, cladding thermal and irradiation creep, cladding irradiation growth , gap heat transfer, and gap/plenum gas behavior during irradiation. The various modeling capabilities are demonstrated using a 2D axisymmetric analysis of the upper section of a simplified multi-pellet fuel rod, during both steady and transient operation. Computational results demonstrate the importance of a multidimensional fully-coupled thermomechanics treatment. Interestingly, many of the inherent deficiencies in existing fuel performance codes (e.g., 1D thermomechanics, loose thermo-mechanical coupling, separate steady and transient analysis, cumbersome pre- and post-processing) are, in fact, ABAQUS strengths.

  2. Enhancing the ABAQUS Thermomechanics Code to Simulate Multidimensional Steady and Transient Fuel Rod Behavior

    Williamson, R.L.; Knoll, D.A. [Idaho National Laboratory, PO Box 1625, Idaho Falls, ID 83415-3855 (United States)

    2009-06-15

    Important aspects of fuel rod behavior, for example pellet-clad interaction (PCI), fuel fracture, and non-axisymmetric cooling and oxide formation, are inherently 3-D. Current fuel rod simulation codes typically approximate such behavior using a quasi 2D (or 1.5D) approach and, often, separate codes must be used for steady and transient (or accident) conditions. Notable exceptions are the EPRI propriety code FALCON which is 2D and can be applied to steady or transient operation, and TOUTATIS which is 3D. Recent studies have indicated the need for multidimensional fuel rod simulation capability, particularly for accurate predictions of PCI. The Idaho National Laboratory (INL) is currently developing next-generation capability to model nuclear fuel performance. The goal is to develop a 2D/3D computer code (BISON) which solves the fully coupled thermomechanics equations, includes multi-physics constitutive behavior for both fuel and cladding materials, and is designed for efficient use on highly parallel computers. To provide guidance and a proto-typing environment for this effort, plus provide the INL with near-term fuel modeling capability, the commercially available ABAQUS thermomechanics software has been enhanced to include the fuel behavior phenomena necessary to afford a practical fuel performance simulation capability. This paper details the enhancements which have been implemented in ABAQUS to date, and provides results of a multi-pellet fuel problem which demonstrates the new capability. ABAQUS employs modern finite element methods to solve the nonlinear thermomechanics equations in 1, 2, or 3-D, using linear or quadratic elements. The temperature and displacement fields are solved in a fully-coupled fashion, using sophisticated iteration and time integration error control. The code includes robust contact algorithms, essential for computing multidimensional pellet-pellet or pellet-clad interaction. Extensive constitutive models are available, including

  3. Enhancing the ABAQUS Thermomechanics Code to Simulate Multidimensional Steady and Transient Fuel Rod Behavior

    Important aspects of fuel rod behavior, for example pellet-clad interaction (PCI), fuel fracture, and non-axisymmetric cooling and oxide formation, are inherently 3-D. Current fuel rod simulation codes typically approximate such behavior using a quasi 2D (or 1.5D) approach and, often, separate codes must be used for steady and transient (or accident) conditions. Notable exceptions are the EPRI propriety code FALCON which is 2D and can be applied to steady or transient operation, and TOUTATIS which is 3D. Recent studies have indicated the need for multidimensional fuel rod simulation capability, particularly for accurate predictions of PCI. The Idaho National Laboratory (INL) is currently developing next-generation capability to model nuclear fuel performance. The goal is to develop a 2D/3D computer code (BISON) which solves the fully coupled thermomechanics equations, includes multi-physics constitutive behavior for both fuel and cladding materials, and is designed for efficient use on highly parallel computers. To provide guidance and a proto-typing environment for this effort, plus provide the INL with near-term fuel modeling capability, the commercially available ABAQUS thermomechanics software has been enhanced to include the fuel behavior phenomena necessary to afford a practical fuel performance simulation capability. This paper details the enhancements which have been implemented in ABAQUS to date, and provides results of a multi-pellet fuel problem which demonstrates the new capability. ABAQUS employs modern finite element methods to solve the nonlinear thermomechanics equations in 1, 2, or 3-D, using linear or quadratic elements. The temperature and displacement fields are solved in a fully-coupled fashion, using sophisticated iteration and time integration error control. The code includes robust contact algorithms, essential for computing multidimensional pellet-pellet or pellet-clad interaction. Extensive constitutive models are available, including

  4. Description of modelling to be implemented in the fuel rod thermomechanics code Cyrano3

    CYRANO3 is the new EDF thermomechanical code developed to evaluate the overall fuel rod behavior under irradiation. In that context, this paper presents the phenomena to be simulated and the correlations adopted for modelling purposes. The empirical models presented are taken from the CYRANO2 code and a compilation of the relevant literature. The present revision corrects and supplements version B on the basis of its use during the software coding phase from January 1991 to May 1993. (authors). figs., tabs., 120 refs

  5. Thermomechanical DART code improvements for LEU VHD dispersion and monolithic fuel element analysis

    A collaboration agreement between ANL/US DOE and CNEA Argentina in the area of Low Enriched Uranium Advanced Fuels has been in place since October 16, 1997 under the Implementation Arrangement for Technical Exchange and Cooperation in the Area of Peaceful Uses of Nuclear Energy. An annex concerning DART code optimization has been operative since February 8, 1999. Previously, as a part of this annex a visual FASTDART version and also a DART THERMAL version were presented during RERTR 2000, 2002 and RERTR 2003 Meetings. During this past year the following activities were completed: Optimization of DART TM code Al diffusion parameters by testing predictions against reliable data from RERTR experiments. Improvements on the 3-D thermo-mechanical version of the code for modeling the irradiation behavior of LEU U-Mo monolithic fuel. Concerning the first point, by means of an optimization of parameters of the Al diffusion through the interaction product theoretical expression, a reasonable agreement between DART temperature calculations with reliable RERTR PIE data was reached. The 3-D thermomechanical code complex is based upon a finite element thermal-elastic code named TERMELAS, and irradiation behavior provided by the DART code. An adequate and progressive process of coupling calculations of both codes at each time step is currently developed. Compatible thermal calculation between both codes was reached. This is the first stage to benchmark and validate against RERTR PIE data the coupling process. (author)

  6. RODSWELL: a computer code for the thermomechanical analysis of fuel rods under LOCA conditions

    The present report is the user's manual for the computer code RODSWELL developed at the JRC-Ispra for the thermomechanical analysis of LWR fuel rods under simulated loss-of-coolant accident (LOCA) conditions. The code calculates the variation in space and time of all significant fuel rod variables, including fuel, gap and cladding temperature, fuel and cladding deformation, cladding oxidation and rod internal pressure. The essential characteristics of the code are briefly outlined here. The model is particularly designed to perform a full thermal and mechanical analysis in both the azimuthal and radial directions. Thus, azimuthal temperature gradients arising from pellet eccentricity, flux tilt, arbitrary distribution of heat sources in the fuel and the cladding and azimuthal variation of coolant conditions can be treated. The code combines a transient 2-dimensional heat conduction code and a 1-dimentional mechanical model for the cladding deformation. The fuel rod is divided into a number of axial sections and a detailed thermomechanical analysis is performed within each section in radial and azimuthal directions. In the following sections, instructions are given for the definition of the data files and the semi-variable dimensions. Then follows a complete description of the input data. Finally, the restart option is described

  7. Implementation of constitutive equations for creep damage mechanics into the ABAQUS finite element code - some practical cases in high temperature component design and life assessment

    Constitutive equations for creep damage mechanics are implemented into the finite element program ABAQUS using a user supplied subroutine, UMAT. A modified Kachanov-Rabotnov constitutive equation which accounts for inhomogeneity in creep damage is used. With a user defined material a number of bench mark tests are analyzed for verification. In the cases where analytical solutions exist, the numerical results agree very well. In other cases, the creep damage evolution response appear to be realistic in comparison with laboratory creep tests. The appropriateness of using the creep damage mechanics concept in design and life assessment of high temperature components is demonstrated. 18 refs

  8. Development of thermal analysis method for the near field of HLW repository using ABAQUS

    Kuh, Jung Eui; Kang, Chul Hyung; Park, Jeong Hwa [Korea Atomic Energy Research Institute, Taejon (Korea)

    1998-10-01

    An appropriate tool is needed to evaluate the thermo-mechanical stability of high level radioactive waste (HLW) repository. In this report a thermal analysis methodology for the near field of HLW repository is developed to use ABAQUS which is one of the multi purpose FEM code and has been used for many engineering area. The main contents of this methodology development are the structural and material modelling to simulate a repository, setup of side conditions, e.g., boundary and load conditions, and initial conditions, and the procedure to selection proper material parameters. In addition to these, the interface programs for effective production of input data and effective change of model size for sensitivity analysis for disposal concept development are developed. The results of this work will be apply to evaluate the thermal stability and to use as main input data for mechanical analysis of HLW repository. (author). 20 refs., 15 figs., 5 tabs.

  9. SATURN-FS 1: A computer code for thermo-mechanical fuel rod analysis

    The SATURN-FS code was written as a general revision of the SATURN-2 code. SATURN-FS is capable to perform a complete thermomechanical analysis of a fuel pin, with all thermal, mechanical and irradiation-based effects. Analysis is possible for LWR and for LMFBR fuel pins. The thermal analysis consists of calculations of the temperature profile in fuel, gap and in the cladding. Pore migration, stoichiometry change of oxide fuel, gas release and diffusion effects are taken into account. The mechanical modeling allows the non steady-state analysis of elastic and nonelastic fuel pin behaviour, such as creep, strain hardening, recovery and stress relaxation. Fuel cracking and healing is taken into account as well as contact and friction between fuel and cladding. The modeling of the irradiation effects comprises swelling and fission gas production, Pu-migration and irradiation induced creep. The code structure, the models and the requirements for running the code are described in the report. Recommendations for the application are given. Program runs for verification and typical examples of application are given in the last part of this report. (orig.)

  10. Coupled Thermo-Mechanical Analyses of Dynamically Loaded Rubber Cylinders

    Johnson, Arthur R.; Chen, Tzi-Kang

    2000-01-01

    A procedure that models coupled thermo-mechanical deformations of viscoelastic rubber cylinders by employing the ABAQUS finite element code is described. Computational simulations of hysteretic heating are presented for several tall and short rubber cylinders both with and without a steel disk at their centers. The cylinders are compressed axially and are then cyclically loaded about the compressed state. The non-uniform hysteretic heating of the rubber cylinders containing a steel disk is presented. The analyses performed suggest that the coupling procedure should be considered for further development as a design tool for rubber degradation studies.

  11. MCTP, a code for the thermo-mechanical analysis of a fuel rod of BWR type reactors (Neutron part)

    In the National Institute of Nuclear Research of Mexico a code for the thermo-mechanical analysis of the fuel rods of the BWR type reactors of the Nucleo electric Central of Laguna Verde is developed. The code solves the diffusion equation in cylindrical coordinates with several energy groups. The code, likewise, calculates the temperature distribution and power distribution in those fuel rods. The code is denominated Multi groups With Temperatures and Power (MCTP). In the code, the energy with which the fission neutrons are emitted it is divided in six groups. They are also considered the produced perturbations by the changes in the temperatures of the materials that constitute the fuel rods, the content of fission products, the uranium consumption and in its case the gadolinium, as well as the plutonium production. In this work there are present preliminary results obtained with the code, using data of operation of the Nucleo electric Central of Laguna Verde. (Author)

  12. Validation of fast reactor thermomechanical and thermohydraulic codes. Final report of a co-ordinated research project. 1996-1999

    This report is a summary of the work performed under a co-ordinated research project (CRP) entitled Harmonization and Validation of Fast Reactor Thermomechanical and Thermo-Hydraulic Codes and Relations using Experimental Data. The project was organized by the IAEA on the recommendation of the IAEA's Technical Working Group on Fast Reactors (TWGFR) and carried out from 1996 to 1999. In certain conditions, temperature fluctuations in the coolant close to a structure caused by thermal striping can lead to thermomechanical damage to structures. Institutes from a number of Member States have an interest in improving engineering tools and prediction techniques concerning the characterization of the thermal striping effects, in which numerical models have a major role. Therefore, the IAEA through its advanced reactor technology development programme supports the activities of Member States in this area. Design analyses applied to thermal striping phenomena need to be firmly established, and the CRP provided a valuable tool in assessing their reliability. Eleven institutes from France, India, Italy, Japan, the Republic of Korea, the Russian Federation and the United Kingdom co-operated in this CRP. This report documents the CRP activities, provides the main results and recommendations and includes the work carried out by the research groups at the participating institutes within the CRP on harmonization and validation of fast reactor thermomechanical and thermohydraulic codes and relations

  13. A new code for predicting the thermo-mechanical and irradiation behavior of metallic fuels in sodium fast reactors

    Karahan, Aydin, E-mail: karahan@mit.ed [Center for Advanced Nuclear Energy Systems, Nuclear Science and Engineering Department, Massachusetts Institute of Technology (United States); Buongiorno, Jacopo [Center for Advanced Nuclear Energy Systems, Nuclear Science and Engineering Department, Massachusetts Institute of Technology (United States)

    2010-01-31

    An engineering code to predict the irradiation behavior of U-Zr and U-Pu-Zr metallic alloy fuel pins and UO{sub 2}-PuO{sub 2} mixed oxide fuel pins in sodium-cooled fast reactors was developed. The code was named Fuel Engineering and Structural analysis Tool (FEAST). FEAST has several modules working in coupled form with an explicit numerical algorithm. These modules describe fission gas release and fuel swelling, fuel chemistry and restructuring, temperature distribution, fuel-clad chemical interaction, and fuel and clad mechanical analysis including transient creep-fracture for the clad. Given the fuel pin geometry, composition and irradiation history, FEAST can analyze fuel and clad thermo-mechanical behavior at both steady-state and design-basis (non-disruptive) transient scenarios. FEAST was written in FORTRAN-90 and has a simple input file similar to that of the LWR fuel code FRAPCON. The metal-fuel version is called FEAST-METAL, and is described in this paper. The oxide-fuel version, FEAST-OXIDE is described in a companion paper. With respect to the old Argonne National Laboratory code LIFE-METAL and other same-generation codes, FEAST-METAL emphasizes more mechanistic, less empirical models, whenever available. Specifically, fission gas release and swelling are modeled with the GRSIS algorithm, which is based on detailed tracking of fission gas bubbles within the metal fuel. Migration of the fuel constituents is modeled by means of thermo-transport theory. Fuel-clad chemical interaction models based on precipitation kinetics were developed for steady-state operation and transients. Finally, a transient intergranular creep-fracture model for the clad, which tracks the nucleation and growth of the cavities at the grain boundaries, was developed for and implemented in the code. Reducing the empiricism in the constitutive models should make it more acceptable to extrapolate FEAST-METAL to new fuel compositions and higher burnup, as envisioned in advanced sodium

  14. A new coupling of the 3D thermal-hydraulic code THYC and the thermo-mechanical code CYRANO3 for PWR calculations

    Among all parameters, the fuel temperature has a significant influence on the reactivity of the core, because of the Doppler effect on cross-sections. Most neutronic codes use a straightforward method to calculate an average fuel temperature used in their specific feed-back models. For instance, EDF's neutronic code COCCINELLE uses the Rowland's formula using the temperatures of the center and the surface of the pellet. COCCINELLE is coupled to the 3D thermal-hydraulic code THYC with calculates TDoppler with is standard thermal model. In order to improve the accuracy of such calculations, we have developed the coupling of our two latest codes in thermal-hydraulics (THYC) and thermo-mechanics (CYRANO3). THYC calculates two-phase flows in pipes or rod bundles and is used for transient calculations such as steam-line break, boron dilution accidents, DNB predictions, steam generator and condenser studies. CYRANO3 calculates most of the phenomena that take place in the fuel such as: 1) heat transfer induced by nuclear power; 2) thermal expansion of the fuel and the cladding; 3) release of gaseous fission's products; 4) mechanical interaction between the pellet and the cladding. These two codes are now qualified in their own field and the coupling, using Parallel Virtual Machine (PVM) libraries customized in an home-made-easy-to-use package called CALCIUM, has been validated on 'low' configurations (no thermal expansion, constant thermal characteristics) and used on accidental transients such as rod ejection and loss of coolant accident. (K.A.)

  15. Thermomechanical analysis of fuel rods during transitory events using the RAMONA and FETMA codes; Analisis termomecanico de barras combustibles durante eventos transitorios usando los codigos RAMONA y FETMA

    Hernandez L, H. [ININ, Departamento de Sistemas Nucleares, Carretera Mexico-Toluca s/n, 52750 Ocoyoacac, Estado de Mexico (Mexico)], e-mail: hector.hernandez@inin.gob.mx

    2009-10-15

    In National Institute of Nuclear Research, the fuel management system (FMS) has been used by long time to simulate the BWR operation in stationary state, as well as during a transitory event. To evaluate the thermomechanical behavior of a fuel element was created and interface between the FMS codes and the fuel element thermo mechanical analysis (FETMA) code properly developed and implemented. In this work, the results of thermomechanical behavior of fuel rods that compose the hot channel during the simulation of a transitory event of a BWR are shown. The transitory events considered in this work are a load rejection and failure in controller of feed water, which are events more important that can to occur in a BWR. The results show that during the developed conditions by both transitory events some failure is not presented in fuel rods. Also, that the transitory event of load rejection is more claimant in security terms that of controller failure of feed water. (Author)

  16. Modelling of the thermomechanical and physical processes in FR fuel pins using the GERMINAL code

    In the frame of the R and D on Fast Reactor mixed oxide fuels, CEA/DEC has developed the computer code GERMINAL for studying fuel pin thermal and mechanical behaviour, both during steady-state and incidental conditions, up to high burn-up (25 at%). The first part of this paper is devoted to the description of the main models: fuel evolution (central hole and porosity evolution, Plutonium redistribution, O/M radial profile, transient gas swelling, melting fuel behaviour, minor actinides production), high burn-up models (fission gas, volatile fission products and JOG formation), fuel-cladding heat transfer, fuel-cladding mechanical interaction. The second part gives some examples of calculation results taken from the GERMINAL validation data base (more than 40 experiments from PHENIX, PFR, CABRI reactors), with special emphasis on: local fission gas retention and global release, fuel geometry evolution, radial redistribution of plutonium for high burn-up fuels, solid and annular fuel behaviour during power ramps including fuel melting, helium formation from MA (Am and Np) doped homogeneous fuels. (author)

  17. Micromechanics-Based Structural Analysis (FEAMAC) and Multiscale Visualization within Abaqus/CAE Environment

    Arnold, Steven M.; Bednarcyk, Brett A.; Hussain, Aquila; Katiyar, Vivek

    2010-01-01

    A unified framework is presented that enables coupled multiscale analysis of composite structures and associated graphical pre- and postprocessing within the Abaqus/CAE environment. The recently developed, free, Finite Element Analysis--Micromechanics Analysis Code (FEAMAC) software couples NASA's Micromechanics Analysis Code with Generalized Method of Cells (MAC/GMC) with Abaqus/Standard and Abaqus/Explicit to perform micromechanics based FEA such that the nonlinear composite material response at each integration point is modeled at each increment by MAC/GMC. The Graphical User Interfaces (FEAMAC-Pre and FEAMAC-Post), developed through collaboration between SIMULIA Erie and the NASA Glenn Research Center, enable users to employ a new FEAMAC module within Abaqus/CAE that provides access to the composite microscale. FEA IAC-Pre is used to define and store constituent material properties, set-up and store composite repeating unit cells, and assign composite materials as sections with all data being stored within the CAE database. Likewise FEAMAC-Post enables multiscale field quantity visualization (contour plots, X-Y plots), with point and click access to the microscale i.e., fiber and matrix fields).

  18. Preliminary thermo-mechanical analysis of ITER breeding blanket

    Kikuchi, Shigeto; Kuroda, Toshimasa; Enoeda, Mikio [Japan Atomic Energy Research Inst., Naka, Ibaraki (Japan). Naka Fusion Research Establishment

    1999-01-01

    Thermo-mechanical analysis has been conducted on ITER breeding blanket taking into account thermo-mechanical characteristics peculiar to pebble beds. The features of the analysis are to adopt an elasto-plastic constitutive model for pebble beds and to take into account spatially varying thermal conductivity and heat transfer coefficient, especially in the Be pebble bed, depending on the stress. ABAQUS code and COUPLED TEMPERATURE-DISPLACEMENT procedure of the code are selected so that thermal conductivity is automatically calculated in each calculation point depending on the stress. The modified DRUCKER-PRAGER/Cap plasticity model for granular materials of the code is selected so as to deal with such mechanical features of pebble bed as shear failure flow and hydrostatic plastic compression, and capability of the model is studied. The thermal property-stress correlation used in the analysis is obtained based on the experimental results at FZK and the results of additional thermo-mechanical analysis performed here. The thermo-mechanical analysis of an ITER breeding blanket module has been performed for four conditions: case A; nominal case with spatial distribution of thermal conductivity and heat transfer coefficient in Be pebble bed depending on the stress, case B; constant thermal conductivity, case C; thermal conductivity = -20% of nominal case, and case D; thermal conductivity = +20% of nominal case. In the nominal case the temperature of breeding material (Li{sub 2}ZrO{sub 3}) ranges from 317degC to 554degC and the maximum temperature of Be pebble bed is 446degC. It is concluded that the temperature distribution is within the current design limits. Though the analyses performed here are preliminary, the results exhibit well the qualitative features of the pebble bed mechanical behaviors observed in experiments. For more detail quantitative estimates of the blanket performance, further investigation on mechanical properties of pebble beds by experiment

  19. Thermomechanical analysis of a fuel rod in a BWR reactor using the FUELSIM code; Analisis termomecanico de una barra de combustible de un reactor BWR utilizando el codigo FUELSIM

    Pantoja C, R. [Escuela Superior de Fisica y Matematicas, Departamento de Ingenieria Nuclear, IPN, Av. Instituto Politecnico Nacional s/n, Col. San Pedro Zacatenco, 07738 Mexico, D. F. (Mexico); Ortiz V, J.; Araiza M, E. [ININ, Departamento de Sistemas Nucleares, Carretera Mexico-Toluca s/n, 52750 Ocoyoacac, Estado de Mexico (Mexico)], e-mail: rapaca78@yahoo.com.mx

    2009-10-15

    The thermomechanical behaviour of a fuel rod exposed to irradiation is a complex process in which are coupled great quantity of interrelated physical-chemical phenomena, for that analysis of rod performance in the core of a nuclear power reactor is realized generally with computation codes that integrate several phenomena expected during the time life of fuel rod in the core. An application of this type of thermomechanical codes is to predict, inside certain reliability margin, the design parameters that would be required to adjust, in order to get a better economy or rod performance, for a systematic approach to the fuel design optimization. FUELSIM is a thermomechanical code based on the models of FRAPCON code, which was developed under auspice of Nuclear Regulatory Commission of USA. FUELSIM allows iterative calculations like part of its programming structure, allowing search of extreme cases of behaviour, probabilistic analysis (or statistical), parametric analysis (or sensibility) and also can include as entrance data to the uncertainties associated with production data, code parameters and associated models. In this work is reported a first analysis of thermomechanical performance of a typical fuel rod used in a BWR 5/6. Results of maximum temperatures are presented in the fuel center and of axial deformation, for the 10 axial nodes in that the active longitude of fuel rod was divided. (Author)

  20. Measurement and Prediction of the Thermomechanical Response of Shape Memory Alloy Hybrid Composite Beams

    Davis, Brian; Turner, Travis L.; Seelecke, Stefan

    2008-01-01

    An experimental and numerical investigation into the static and dynamic responses of shape memory alloy hybrid composite (SMAHC) beams is performed to provide quantitative validation of a recently commercialized numerical analysis/design tool for SMAHC structures. The SMAHC beam specimens consist of a composite matrix with embedded pre-strained SMA actuators, which act against the mechanical boundaries of the structure when thermally activated to adaptively stiffen the structure. Numerical results are produced from the numerical model as implemented into the commercial finite element code ABAQUS. A rigorous experimental investigation is undertaken to acquire high fidelity measurements including infrared thermography and projection moire interferometry for full-field temperature and displacement measurements, respectively. High fidelity numerical results are also obtained from the numerical model and include measured parameters, such as geometric imperfection and thermal load. Excellent agreement is achieved between the predicted and measured results of the static and dynamic thermomechanical response, thereby providing quantitative validation of the numerical tool.

  1. Integrating Moldflow and Abaqus in the Package Simulation Workflow

    Andreasson, Eskil; Persson, Leo; Jacobsson, Henrik; Nordgren, Johan

    2013-01-01

    Tetra Pak has used numerical simulation tools for plastic injection molding (Moldflow) and structural analysis (Abaqus/Implicit and Abaqus/Explicit) for many years. Today these two simulation tools are used independently of each other without any coupling. How these two disciplines can be combined to better predict the mechanical response of a polymer component is presented in this work. The manufacturing process, in this case injection molding, creates the mechanical properties of the produc...

  2. Development of computer codes to perform model calculations for thermomechanical interaction of rock salt with borehole liners in a HLW repository

    The principal objectives of the work are the development of computer codes with suitable material laws for rock salt and to perform model calculations on the thermomechanical phenomena in the near field of a radioactive waste repository. In particular the work was dealing with the following subjects: - Comparison of the computational capabilities of the finite element codes ADINA and MAUS (new version) by model calculations for the temperature test field 3. Thermally induced convergence rates of boreholes in a high level waste (HLW) repository. Investigation of the contact between salt and waste containers or borehole liners, and of the resulting pressure rise. Investigation of the effect of inhomogenities (anhydrite layers) in rock salt on the stress-strain field around a borehole in a HLW repository. Development of a material model for backfill material and performance of model calculations on the convergence of backfilled storage rooms or tunnels in rock salt. Development of a new version of the computer code MAUS by the Institut fuer Elektrische Anlagen und Energiewirtschaft of the RWTH-Aachen

  3. Samovar: a thermomechanical code for modeling of geodynamic processes in the lithosphere-application to basin evolution

    Elesin, Y; Gerya, T; Artemieva, Irina;

    2010-01-01

    We present a new 2D finite difference code, Samovar, for high-resolution numerical modeling of complex geodynamic processes. Examples are collision of lithospheric plates (including mountain building and subduction) and lithosphere extension (including formation of sedimentary basins, regions...... of extended crust, and rift zones). The code models deformation of the lithosphere with viscoelastoplastic rheology, including erosion/sedimentation processes and formation of shear zones in areas of high stresses. It also models steady-state and transient conductive and advective thermal processes including...... partial melting and magma transport in the lithosphere. The thermal and mechanical parts of the code are tested for a series of physical problems with analytical solutions. We apply the code to geodynamic modeling by examining numerically the processes of lithosphere extension and basin formation...

  4. Samovar: a thermomechanical code for modeling of geodynamic processes in the lithosphere-application to basin evolution

    Elesin, Y; Gerya, T; Artemieva, Irina; Thybo, Hans

    2010-01-01

    We present a new 2D finite difference code, Samovar, for high-resolution numerical modeling of complex geodynamic processes. Examples are collision of lithospheric plates (including mountain building and subduction) and lithosphere extension (including formation of sedimentary basins, regions of extended crust, and rift zones). The code models deformation of the lithosphere with viscoelastoplastic rheology, including erosion/sedimentation processes and formation of shear zones in areas of hig...

  5. Description of modelling to be implemented in the fuel rod thermomechanics code Cyrano3; Description des modeles a introduire dans le logiciel de thermomecanique du crayon combustible Cyrano3

    Baron, D.; Bouffioux, P.

    1993-06-01

    CYRANO3 is the new EDF thermomechanical code developed to evaluate the overall fuel rod behavior under irradiation. In that context, this paper presents the phenomena to be simulated and the correlations adopted for modelling purposes. The empirical models presented are taken from the CYRANO2 code and a compilation of the relevant literature. The present revision corrects and supplements version B on the basis of its use during the software coding phase from January 1991 to May 1993. (authors). figs., tabs., 120 refs.

  6. Modelling thermomechanical conditions at the tool/matrix interface in Friction Stir Welding

    Schmidt, Henrik Nikolaj Blich; Hattel, Jesper

    2004-01-01

    is obtained. A fully coupled thermo-mechanical 3D FE model has been developed in ABAQUS/Explicit using the ALE formulation and the Johnson-Cook material law. The contact forces are modelled by Coulomb’s law of friction making the contact condition highly solution dependent. The heat is generated by...

  7. MCTP, a code for the thermo-mechanical analysis of a fuel rod of BWR type reactors (Neutron part); MCTP, un codigo para el analisis termo-mecanico de una barra combustible de reactores tipo BWR (Parte Neutronica)

    Hernandez L, H.; Ortiz V, J. [ININ, 52045 Ocoyoacac, Estado de Mexico (Mexico)]. e-mail: hhl@nuclear.inin.mx

    2003-07-01

    In the National Institute of Nuclear Research of Mexico a code for the thermo-mechanical analysis of the fuel rods of the BWR type reactors of the Nucleo electric Central of Laguna Verde is developed. The code solves the diffusion equation in cylindrical coordinates with several energy groups. The code, likewise, calculates the temperature distribution and power distribution in those fuel rods. The code is denominated Multi groups With Temperatures and Power (MCTP). In the code, the energy with which the fission neutrons are emitted it is divided in six groups. They are also considered the produced perturbations by the changes in the temperatures of the materials that constitute the fuel rods, the content of fission products, the uranium consumption and in its case the gadolinium, as well as the plutonium production. In this work there are present preliminary results obtained with the code, using data of operation of the Nucleo electric Central of Laguna Verde. (Author)

  8. Abaqus/Standard-based quantification of human cardiac mechanical properties

    Genet, Martin; Kuhl, Ellen; Guccione, Julius

    2016-01-01

    Computational modeling can provide critical insight into existing and potential new surgical procedures, medical or minimally-invasive treatments for heart failure, one of the leading causes of deaths in the world that has reached epidemic proportions. In this paper, we present our Abaqus/Standard-based pipeline to create subject-specific left ventricular models. We first review our generic left ventricular model, and then the personalization process based on magnetic resonance images. Identification of subject-specific cardiac material properties is done by coupling Abaqus/Standard to the python optimization library NL-Opt. Compared to previous studies from our group, the emphasis is here on the fully implicit solving of the model, and the two-parameter optimization of the passive cardiac material properties.

  9. Analysis of SMA Hybrid Composite Structures in MSC.Nastran and ABAQUS

    Turner, Travis L.; Patel, Hemant D.

    2005-01-01

    A thermoelastic constitutive model for shape memory alloy (SMA) actuators and SMA hybrid composite (SMAHC) structures was recently implemented in the commercial finite element codes MSC.Nastran and ABAQUS. The model may be easily implemented in any code that has the capability for analysis of laminated composite structures with temperature dependent material properties. The model is also relatively easy to use and requires input of only fundamental engineering properties. A brief description of the model is presented, followed by discussion of implementation and usage in the commercial codes. Results are presented from static and dynamic analysis of SMAHC beams of two types; a beam clamped at each end and a cantilever beam. Nonlinear static (post-buckling) and random response analyses are demonstrated for the first specimen. Static deflection (shape) control is demonstrated for the cantilever beam. Approaches for modeling SMAHC material systems with embedded SMA in ribbon and small round wire product forms are demonstrated and compared. The results from the commercial codes are compared to those from a research code as validation of the commercial implementations; excellent correlation is achieved in all cases.

  10. Impact-Contact Analysis of Prismatic Graphite Blocks Using Abaqus

    Graphite blocks are the important core components of the high temperature gas-cooled reactor. As these blocks are simply stacked in array, collisions among neighboring components may occur during earthquakes or accidents. The final objective of the research project is to develop a reliable seismic model of the stacked graphite blocks from which their behavior can be predicted and, thus, they are designed to have sufficient strength to maintain their structural integrity during the anticipated occurrences. The work summarized in this report is a first step toward the big picture and is dedicated to build a realistic impact-contact dynamics model of the graphite block using a commercial FEM package, Abaqus. The developed model will be further used to assist building a reliable lumped dynamics model of these stacked graphite components

  11. Thermomechanical treatment of steel

    Thermomechanical treatment is defined as a process in which a forming operation is carried out in the course of a treatment in order to improve the mechanical properties of a material. Several thermomechanical processes for the treatment of steel are described. (WBU)

  12. Thermo-mechanical interaction effects in foam cored sandwich panels-correlation between High-order models and Finite element analysis results

    Palleti, Hara Naga Krishna Teja; Santiuste, Carlos; Thomsen, Ole Thybo;

    2010-01-01

    Thermo-mechanical interaction effects including thermal material degradation in polymer foam cored sandwich structures is investigated using the commercial Finite Element Analysis (FEA) package ABAQUS/Standard. Sandwich panels with different boundary conditions in the form of simply supported or...

  13. Input Files and Procedures for Analysis of SMA Hybrid Composite Beams in MSC.Nastran and ABAQUS

    Turner, Travis L.; Patel, Hemant D.

    2005-01-01

    A thermoelastic constitutive model for shape memory alloys (SMAs) and SMA hybrid composites (SMAHCs) was recently implemented in the commercial codes MSC.Nastran and ABAQUS. The model is implemented and supported within the core of the commercial codes, so no user subroutines or external calculations are necessary. The model and resulting structural analysis has been previously demonstrated and experimentally verified for thermoelastic, vibration and acoustic, and structural shape control applications. The commercial implementations are described in related documents cited in the references, where various results are also shown that validate the commercial implementations relative to a research code. This paper is a companion to those documents in that it provides additional detail on the actual input files and solution procedures and serves as a repository for ASCII text versions of the input files necessary for duplication of the available results.

  14. Modelling of friction anisotropy of deepdrawing sheet in ABAQUS/EXPLICIT

    F. Stachowicz; Trzepieciński, T.

    2010-01-01

    This paper presents the experimental and numerical results of rectangular cup drawing of steel sheets. The aim of the experimental study was to analyze material behavior under deformation. The received results were further used to verify the results from numerical simulation by taking friction and material anisotropy into consideration. A 3D parametric finite element (FE) model was built using the FE-package ABAQUS/Standard. ABAQUS allows analyzing physical models of real processes putting s...

  15. Analysis of SMA hybrid composite structures using commercial codes

    Turner, Travis L.; Patel, Hemant D.

    2004-07-01

    A thermomechanical model for shape memory alloy (SMA) actuators and SMA hybrid composite (SMAHC) structures has been recently implemented in the commercial finite element codes MSC.Nastran and ABAQUS. The model may be easily implemented in any code that has the capability for analysis of laminated composite structures with temperature dependent material properties. The model is also relatively easy to use and requires input of only fundamental engineering properties. A brief description of the model is presented, followed by discussion of implementation and usage in the commercial codes. Results are presented from static and dynamic analysis of SMAHC beams of two types; a beam clamped at each end and a cantilevered beam. Nonlinear static (post-buckling) and random response analyses are demonstrated for the first specimen. Static deflection (shape) control is demonstrated for the cantilevered beam. Approaches for modeling SMAHC material systems with embedded SMA in ribbon and small round wire product forms are demonstrated and compared. The results from the commercial codes are compared to those from a research code as validation of the commercial implementations; excellent correlation is achieved in all cases.

  16. Thermomechanical analysis of fast-burst reactors

    Fast-burst reactors are designed to provide intense, short-duration pulses of neutrons. The fission reaction also produces extreme time-dependent heating of the nuclear fuel. An existing transient-dynamic finite element code was modified specifically to compute the time-dependent stresses and displacements due to thermal shock loads of reactors. Thermomechanical analysis was then applied to determine structural feasibility of various concepts for an EDNA-type reactor and to optimize the mechanical design of the new SPR III-M reactor

  17. Thermo-Mechanical Simulation of Brake Disc Frictional Character by Moment of Inertia

    Fei Gao

    2014-01-01

    The distribution of temperatures gradient and thermal stress of brake disc has been simulated by FEM code to make brake disc thermal stress more homogenously. In this study, using moment of inertia to simulate the realistic brake process instead of theoretically predefines the train deceleration rate, nonlinear deceleration rate and thermo-mechanical behavior has been revealed. The FEM models build upon LS-DYNA® thermo-mechanical code and contact algorithm. Non-uniform temperature alone disc ...

  18. Toward high-speed 3D nonlinear soft tissue deformation simulations using Abaqus software.

    Idkaidek, Ashraf; Jasiuk, Iwona

    2015-12-01

    We aim to achieve a fast and accurate three-dimensional (3D) simulation of a porcine liver deformation under a surgical tool pressure using the commercial finite element software Abaqus. The liver geometry is obtained using magnetic resonance imaging, and a nonlinear constitutive law is employed to capture large deformations of the tissue. Effects of implicit versus explicit analysis schemes, element type, and mesh density on computation time are studied. We find that Abaqus explicit and implicit solvers are capable of simulating nonlinear soft tissue deformations accurately using first-order tetrahedral elements in a relatively short time by optimizing the element size. This study provides new insights and guidance on accurate and relatively fast nonlinear soft tissue simulations. Such simulations can provide force feedback during robotic surgery and allow visualization of tissue deformations for surgery planning and training of surgical residents. PMID:26530842

  19. Modelling and finite element simulation for FDSC multi-point forming based on ABAQUS

    Weiwei, Wan; Binbin, Jia; Tingting, Sun; He, Di; Chen, Zhao

    2015-01-01

    This paper introduces the modeling and FEM simulation of FDSC Multi-Point Forming based on ABAQUS. Python is used as programming languages to secondary develop the software and to establish a simulation platform. An additional module was developed for the automatic modeling with the functions of: (a) basic parameters input such as material performance, plate size (b) rapid assembly of MPF punches and sheet automatically (c)automatic definition of the analytical step and the output of variable...

  20. Developing an Abaqus *HYPERFOAM Model for M9747 (4003047) Cellular Silicone Foam

    Siranosian, Antranik A. [Los Alamos National Laboratory; Stevens, R. Robert [Los Alamos National Laboratory

    2012-04-26

    This report documents work done to develop an Abaqus *HYPERFOAM hyperelastic model for M9747 (4003047) cellular silicone foam for use in quasi-static analyses at ambient temperature. Experimental data, from acceptance tests for 'Pad A' conducted at the Kansas City Plant (KCP), was used to calibrate the model. The data includes gap (relative displacement) and load measurements from three locations on the pad. Thirteen sets of data, from pads with different serial numbers, were provided. The thirty-nine gap-load curves were extracted from the thirteen supplied Excel spreadsheets and analyzed, and from those thirty-nine one set of data, representing a qualitative mean, was chosen to calibrate the model. The data was converted from gap and load to nominal (engineering) strain and nominal stress in order to implement it in Abaqus. Strain computations required initial pad thickness estimates. An Abaqus model of a right-circular cylinder was used to evaluate and calibrate the *HYPERFOAM model.

  1. Coupled thermomechanical modeling using dissimilar geometries in arpeggio.

    Kostka, Timothy D.; Templeton, Jeremy Alan

    2010-11-01

    Performing coupled thermomechanical simulations is becoming an increasingly important aspect of nuclear weapon (NW) safety assessments in abnormal thermal environments. While such capabilities exist in SIERRA, they have thus far been used only in a limited sense to investigate NW safety themes. An important limiting factor is the difficulty associated with developing geometries and meshes appropriate for both thermal and mechanical finite element models, which has limited thermomechanical analysis to simplified configurations. This work addresses the issue of how to perform coupled analyses on models where the underlying geometries and associated meshes are different and tailored to their relevant physics. Such an approach will reduce the model building effort and enable previously developed single-physics models to be leveraged in future coupled simulations. A combined-environment approach is presented in this report using SIERRA tools, with quantitative comparisons made between different options in SIERRA. This report summarizes efforts on running a coupled thermomechanical analysis using the SIERRA Arpeggio code.

  2. Finite Element Analysis of Progressive Failure and Strain Localization of Carbon Fiber/Epoxy Composite Laminates by ABAQUS

    Liu, P. F.; Yang, Y. H.; Gu, Z. P.; Zheng, J. Y.

    2015-12-01

    Interaction mechanism between the intralaminar damage and interlaminar delamination of composite laminates is always a challenging issue. It is important to consider the progressive failure and strain softening behaviors simultaneously during the damage modeling and numerical simulation of composites using FEA. This paper performs three-dimensional finite element analysis of the progressive failure and strain localization of composites using FEA. An intralaminar progressive failure model based on the strain components is proposed and the nonlinear cohesive model is used to predict the delamination growth. In particular, the nonlocal integral theory which introduces a length scale into the governing equations is used to regularize the strain localization problems of composite structures. Special finite element codes are developed using ABAQUS to predict the intralaminar and interlaminar damage evolution of composites simultaneously. The carbon fiber/epoxy composite laminates with a central hole demonstrates the developed theoretical models and numerical algorithm by discussing the effects of the mesh sizes and layups patterns. It is shown the strain localization problem can be well solved in the progressive failure analysis of composites when the energy dissipation due to the damage of the fiber, matrix and interface occurs at a relatively wide area.

  3. A local model for the thermomechanical conditions in friction stir welding

    Schmidt, H.; Hattel, J.

    2005-01-01

    The conditions under which the deposition process in friction stir welding is successful are not fully understood. However, it is known that only under specific thermomechanical conditions does a weld formation occur. If these conditions are not present, void formation will occur leading to a faulty weld. The objective of the present work is to analyse the primary conditions under which the cavity behind the tool is filled. For this, a fully coupled thermomechanical three-dimensional FE model has been developed in ABAQUS/Explicit using the arbitrary Lagrangian-Eulerian formulation and the Johnson-Cook material law. The model accounts for the compressibility by including the elastic response of the aluminium matrix. The contact forces are modelled by Coulomb's Law of friction, making the contact condition highly solution dependent. Furthermore, separation between the workpiece and the tool is allowed. This is often neglected in other models. Once non-recoverable separation is estimated by the model, a void develops. This is suggested as a preliminary criterion for evaluating the success of the deposition process. Of special interest is the contact condition along the tool/matrix interface, which controls the efficiency of the deposition process. In most models presented previously in the literature, the material flow at the tool interface is prescribed as boundary conditions. In all other contact models, the material is forced to keep contact with the tool. Therefore, the models are unable to predict when the suitable thermomechanical conditions and welding parameters are present. In the present work, the quasi-stationary thermomechanical state in the workpiece is established by modelling the dwell and weld periods. The different thermomechanical states in the colder, stiffer far-field matrix and the hotter, softer near-field matrix (under the tool) result in contact at the tool/matrix interface, thus, no void formation is observed. The steady-state model results

  4. Quasi-static analysis of leg mating unit with ABAQUS/Explicit%基于ABAQUS/Explicit的桩腿耦合缓冲器准静态分析

    夏天; 张世联; 郑轶刊; 彭大炜

    2011-01-01

    The Leg Mating Unit with rubber-metal pads as a buffer is applied in offshore superstructure installation to reduce mating force and accommodate large relative displacement. In design, much attention should be paid to the geometry, material and boundary nonlinearity involved in the LMU structure. In this paper, the 3-D FE model is created and its vertical and horizonrtal load cases are simulated with quasistatic method by ABAQUS/Explicit. The results are interpreted in terms of energy, contact, stiffness, stress and strain, which are reasonable enough to indicate that the LMU structure has strong strength and the simulating method employed here are feasible. Furthermore, some suggestions are given to improve the present structure. The results in the paper are helpful to the design optimization of the leg mating unit.%桩腿耦合缓冲器在应用中主要起减小撞击力和限制上下结构相对位移的作用.在设计时,必须考虑到橡胶材料的大变形、橡胶-钢的接触和摩擦问题,它具有几何、材料和边界的三种非线性.通过结构非线性有限元软件ABAQUS/Explicit建立了桩腿耦合缓冲器的三维体单元模型,用基于中心差分法的准静态法,对其在水平和垂直两种工况下的准静力变形过程进行了数值仿真,从能量、接触、刚度与吸能以及应力应变等各方面对计算结果及其合理性进行了分析,并针对现有结构尺寸提出了改进建议.分析表明使用准静态分析方法是可行的,对桩腿耦合缓冲器的优化设计具有一定参考价值.

  5. Thermomechanical evaluation of the fuel assemblies fabricated in the ININ

    The pilot plant of fuel production of the National Institute of Nuclear Research (ININ) provided to the Laguna Verde Nuclear Power Plant (CNLV) four fuel assemblies type GE9B. The fuel irradiation was carried out in the unit 1 of the CNLV during four operation cycles, highlighting the fact that in their third cycle the four assemblies were placed in the center of the reactor core. In the Nuclear Systems Department (DSN) of the ININ it has been carried out studies to evaluate their neutron performance and to be able to determine the exposure levels of this fuels. Its also outlines the necessity to carry out a study of the thermomechanical behavior of the fuel rods that compose the assemblies, through computational codes that simulate their performance so much thermal as mechanical. For such purpose has been developing in the DSN the FETMA code, together with the codes that compose the system Fuel Management System (FMS), which evaluates the thermomechanical performance of fuel elements. In this work were used the FETMA and FEMAXI codes (developed by JAERI) to study the thermomechanical performance of the fuel elements manufactured in the ININ. (Author)

  6. Thermomechanical properties of hafnium hydride

    Fine bulk samples of delta-phase Hf hydride with various hydrogen contents (CH) ranging from 1.62 to 1.72 in the atomic ratio (H/Hf) were prepared, and their thermomechanical properties were characterized. At room temperature, the sound velocity and Vickers hardness were measured. The elastic modulus was calculated from the measured sound velocity. In the temperature range from room temperature to 673 K, the thermal expansion was measured by using a dilatometer, and the linear thermal expansion coefficient was calculated. Empirical equations describing the thermomechanical properties of Hf hydride as a function of CH were proposed. (author)

  7. A coupled thermo-mechanical model of friction stir welding

    Veljić Darko M.

    2012-01-01

    Full Text Available A coupled thermo-mechanical model was developed to study the temperature fields, the plunge force and the plastic deformations of Al alloy 2024-T351 under different rotating speed: 350, 400 and 450 rpm, during the friction stir welding (FSW process. Three-dimensional FE model has been developed in ABAQUS/Explicit using the arbitrary Lagrangian-Eulerian formulation, the Johnson-Cook material law and the Coulomb’s Law of friction. Numerical results indicate that the maximum temperature in the FSW process is lower than the melting point of the welding material. The temperature filed is approximately symmetrical along the welding line. A lower plastic strain region can be found near the welding tool in the trailing side on the bottom surface. With increasing rotation speed, the low plastic strain region is reduced. When the rotational speed is increased, the plunge force can be reduced. Regions with high equivalent plastic strains are observed which correspond to the nugget and the flow arm.

  8. Numerical modelling of thermal phenomena in laser beam and hybrid welding processes using Abaqus FEA

    W. Piekarska

    2011-04-01

    Full Text Available This paper concerns numerical analysis of thermal phenomena accompanying laser beam and laser-arc hybrid welding processes.Temperature field was obtained on the basis of the solution into energy conservation equation with Fourier law using finite elementmethod. ABAQUS/Standard solver was used for calculations. Electric arc and laser beam heat sources were described respectively by“double ellipsoidal” heat source and Gaussian distribution with assumption of linear decrease of heat source power intensity with material penetration deep. Heat source movement along welded plate was obtained using DFLUX subroutine. Thermo-physical parametersdependant on temperature as well as latent heat of fusion were taken into account in FE analysis. The results of calculations includetemperature field in rectangular elements butt welded by a single laser beam and hybrid laser-arc technique.

  9. Dynamic Analysis of the Arch Concrete Dam under Earthquake Force with ABAQUS

    M.A. Lotfollahi Yaghin

    2008-01-01

    Full Text Available In this study, the dynamical behavior of arch concrete dams has been analyzed by finite element method. The case study is Karoon-1 (shahid Abbaspoor, double curvature arch dam with the height of 200 m. This dam is considered as one of the most complex dams because of different external and internal radius and angles, also, asymmetrical center of external and internal archs in different levels. So, by geometrical dimensions of the mentioned dam from related designing maps and also its mechanical and physical properties, dam without supports and dam with rock supports are modeled by ABAQUS finite element software. According to dynamical analysis results, have been calculated the time history of main stress, displacement of the dam in crest and river bed level and also, their maximum values in earthquake time duration have been compared and investigated.

  10. Application of Abaqus to analysis of the temperature field in elements heated by moving heat sources

    W. Piekarska

    2010-10-01

    Full Text Available Numerical analysis of thermal phenomena occurring during laser beam heating is presented in this paper. Numerical models of surface andvolumetric heat sources were presented and the influence of different laser beam heat source power distribution on temperature field wasanalyzed. Temperature field was obtained by a numerical solution the transient heat transfer equation with activity of inner heat sources using finite element method. Temperature distribution analysis in welded joint was performed in the ABAQUS/Standard solver. The DFLUXsubroutine was used for implementation of the movable welding heat source model. Temperature-depended thermophysical properties for steelwere assumed in computer simulations. Temperature distribution in laser beam surface heated and butt welded plates was numericallyestimated.

  11. Thermomechanical analysis of nuclear fuel elements

    This work presents development of a code to obtain the thermomechanical analysis of fuel rods in the fuel assemblies inserted in the core of BWR reactors. The code uses experimental correlations developed in several laboratories. The development of the code is divided in two parts: a) the thermal part and b) the mechanical part, extending both the fuel and the cladding materials. The thermal part consists of finding the radial distribution of temperatures in the pellet, from the fuel centerline up to the coolant, along the total active length, considering one and two phase flow in the coolant, as a result of the pressure drop in the system. The mechanical part analyzes the effects of temperature gradients, pressure and irradiation, to which the fuel rod is subjected. The strains produced by swelling, creep and thermal stress in the fuel material are analyzed. In the same way the strains in the cladding are analyzed, considering the effects produced by the pressure exerted on the cladding by pellet swelling, by the pressure caused by fission gas release toward the cavities, and by the strain produced on the cladding by the pressure changes of the system. (Author)

  12. Thermomechanical properties of selected shales

    The experimental work discussed in this report is part of an ongoing program concerning evaluation of sedimentary and other rock types as potential hosts for a geologic repository. The objectives are the development of tools and techniques for repository characterization and performance assessment in a diversity of geohydrologic settings. This phase of the program is a laboratory study that investigates fundamental thermomechanical properties of several different shales. Laboratory experiments are intrinsically related to numerical modeling and in situ field experiments, which together will be used for performance assessment

  13. SIMULATION OF COMPLEX THERMOMECHANICAL FATIGUE

    R.Bardenheier; G.Rogers

    2004-01-01

    Two different types of experimental techniques to perform non-isothermal, unicxial and biaxial fatigue testa were described. A new miniaturised electrothermalmechanical test rig was presented and discussed. It enables testing of small specimens under complex thermomechanical loading conditions. In order to cope with the simulation of well defined biaxial proportional and non-proportional loadings with in-phase and out-of-phase superposition of thermal loads a cruciform biaxial fatigue testing machine has been developed. Special design features of both machines, and the specimens tested, as well as typical test results were discussed.

  14. Thermomechanical properties of selected shales

    Hansen, F.D.; Vogt, T.J.

    1987-08-01

    The experimental work discussed in this report is part of an ongoing program concerning evaluation of sedimentary and other rock types as potential hosts for a geologic repository. The objectives are the development of tools and techniques for repository characterization and performance assessment in a diversity of geohydrologic settings. This phase of the program is a laboratory study that investigates fundamental thermomechanical properties of several different shales. Laboratory experiments are intrinsically related to numerical modeling and in situ field experiments, which together will be used for performance assessment.

  15. Thermohydraulics design and thermomechanics analysis of two European breeder blanket concepts for DEMO. Pt. 1 and Pt. 2. Pt. 1: BOT helium cooled solid breeding blanket. Pt. 2: Dual coolant self-cooled liquid metal blanket

    Two different breeding blanket concepts are being elaborated at Forschungszentrum Karlsruhe within the framework of the DEMO breeding blanket development, the concept of a helium cooled solid breeding blanket and the concept of a self-cooled liquid metal blanket. The breeder material used in the first concept is Li4SiO4 as a pebble bed arranged separate from the beryllium pebble bed, which serves as multiplier. The breeder material zone is cooled by several toroidally-radially configurated helium cooling plates which, at the same time, act as reinforcements of the blanket structures. In the liquid metal blanket concept lead-lithium is used both as the breeder material and the coolant. It flows at low velocity in poloidal direction downwards and back in the blanket front zone. In both concepts the First Wall is cooled by helium gas. This report deals with the thermohydraulics design and thermomechanics analysis of the two blanket concepts. The performance data derived from the Monte-Carlo computations serve as a basis for the design calculations. The coolant inlet and outlet temperatures are chosen with the design criteria and the economics aspects taken into account. Uniform temperature distribution in the blanket structures can be achieved by suitable branching and routing of the coolant flows which contributes to reducing decisively the thermal stress. The computations were made using the ABAQUS computer code. The results obtained of the stresses have been evaluated using the ASME code. It can be demonstrated that all maximum values of temperature and stress are below the admissible limit. (orig.)

  16. 基于ABAQUS?R的复合材料跨尺度失效分析软件开发

    薛斌; 李星

    2015-01-01

    复合材料跨尺度失效理论是近些年提出的一类基于物理失效模式的强度理论,它从细观层面判定纤维和基体的失效,在分析复合材料性能匹配和耐久性方面有独特的优势. 提出了一种新的跨尺度失效判定准则,利用Abaqus?R的内嵌Python脚本语言开发了复合材料跨尺度失效分析软件CMFAS,编制了图形用户界面(GUI)进行人机交互,实现了代表体积单元(RVE)参数化建模及后处理、应力放大系数矩阵生成、失效准则临界值求解和损伤演化处理等一系列功能,最终生成Abaqus?R子程序文件USDFLD和VUSDFLD.%Composite multiscale failure theory is a newly proposed category of strength criteria, based on mechanical failure modes. In this theory, fiber and matrix failure are determined in meso level, which has special advantage in analyzing material property matching and durability. A new multiscale failure criteria was proposed, CMFAS (Composite Multiscale Failure Analysis Software) was developed using Python scripting language embedded in Abaqus?R . In CMFAS, GUI (Graphic User Interface) was compiled to realize human-computer interaction, RVE (Representative Volume Element) parametric modeling and post processing, stress amplification factors generation, failure criteria critical value solving and damage evolution were automatically accomplished, finally Abaqus?R subroutine files USDFLD and VUSDFLD were given.

  17. Simulation of thermomechanical fatigue in solder joints

    Fang, H.E.; Porter, V.L.; Fye, R.M.; Holm, E.A. [Sandia National Labs., Albuquerque, NM (United States)

    1997-12-31

    Thermomechanical fatigue (TMF) is a very complex phenomenon in electronic component systems and has been identified as one prominent degradation mechanism for surface mount solder joints in the stockpile. In order to precisely predict the TMF-related effects on the reliability of electronic components in weapons, a multi-level simulation methodology is being developed at Sandia National Laboratories. This methodology links simulation codes of continuum mechanics (JAS3D), microstructural mechanics (GLAD), and microstructural evolution (PARGRAIN) to treat the disparate length scales that exist between the macroscopic response of the component and the microstructural changes occurring in its constituent materials. JAS3D is used to predict strain/temperature distributions in the component due to environmental variable fluctuations. GLAD identifies damage initiation and accumulation in detail based on the spatial information provided by JAS3D. PARGRAIN simulates the changes of material microstructure, such as the heterogeneous coarsening in Sn-Pb solder, when the component`s service environment varies.

  18. In the Structural Modal Analysis Application of ABAQUS Based on Python%基于Python的ABAQUS在结构模态分析上的应用

    禹文涛; 徐航; 梁军勇

    2012-01-01

    The python script interface is provided by ABAQUS for programmers aimed at second-developed ABAQUS. Executing python script at ABAQUS environment, may automatically-setting-up, repeat and modify models and analysis tasks expediently, may realize parametric study and access output database, etc. In this paper, a coupling as an example to introduce based on the ABAQUS Python in structural modal analysis application.%ABAQUS为二次开发用户提供了Python脚本接口。在ABAQUS环境下执行Python脚本,可方便地实现自动化创建、重复、修改模型及分析任务,实现参数化研究,访问结果数据库等功能。以某联轴器为例,介绍了基于Python的ABAQUS在结构模态分析上的应用。

  19. 钢包预热过程热应力影响因子及预报模型%Classification of thermomechanical impact factors and prediction model for ladle preheating

    金胜利; Harald Harmuth; Dietmar Gruber; Thomas Auer; 李亚伟

    2011-01-01

    Linear elastic models were established by means of finite element code ABAQUS to simulate the thermomechanical behavior of steel ladle during preheating. The impact factors of ladle lining thickness and material properties on the maximum stress at steel ladle linings and end temperature at the steel shell were determined. Prediction models were built with partial least squares algorithm based on the above simulation results. The results show that the material properties of working lining plays a major role in the maximum compressive stress, maximum tensile stress and end temperature whether it includes an insulation or not. Compared with the ladle without an insulation, the importance of permanent lining to the maximum stress is reduced significantly by using the insulation.%运用有限元软件ABAQUS建立钢包包衬的线性弹性模型,模拟钢包预热过程包衬的热应力,分析包衬厚度及其材料物理性能对包衬内最大热应力和钢壳表面温度的影响;采用偏最小二乘法建立包衬厚度及材料物理性能与包衬内最大热应力、钢壳表面温度间的预报模型.结果表明,工作衬材料物理性能对包衬最大应力和钢壳表面温度起主要影响作用;较之于无绝热衬,有绝热衬钢包永久衬材料物理性能对钢包热应力和钢壳表面温度的影响作用显著降低.

  20. Nuclear, thermo-mechanical and tritium release analysis of ITER breeding blanket

    The design of the breeding blanket in ITER applies pebble bed breeder in tube (BIT) surrounded by multiplier pebble bed. It is assumed to use the same module support mechanism and coolant manifolds and coolant system as the shielding blankets. This work focuses on the verification of the design of the breeding blanket, from the viewpoints which is especially unique to the pebble bed type breeding blanket, such as, tritium breeding performance, tritium inventory and release behavior and thermo-mechanical performance of the ITER breeding blanket. With respect to the neutronics analysis, the detailed analyses of the distribution of the nuclear heating rate and TBR have been performed in 2D model using MCNP to clarify the input data for the tritium inventory and release rate analyses and thermo-mechanical analyses. With respect to the tritium inventory and release behavior analysis, the parametric analyses for selection of purge gas flow rate were carried out from the view point of pressure drop and the tritium inventory/release performance for Li2TiO3 breeder. The analysis result concluded that purge gas flow rate can be set to conventional flow rate setting (88 l/min per module) to 1/10 of that to save the purge gas flow and minimize the size of purge gas pipe. However, it is necessary to note that more tritium is transformed to HTO (chemical form of water) in case of Li2TiO3 compared to other breeder materials. With respect to the thermo-mechanical analyses of the pebble bed blanket structure, the analyses have been performed by ABAQUS with 2D model derived from one of eight facets of a blanket module, based on the reference design. Analyses were performed to identify the temperature distribution incorporating the pebble bed mechanical simulation and influence of mechanical behavior to the thermal behavior. The result showed that the maximum temperature in the breeding material was 617degC in the first row of breeding rods and the minimum temperature was 328degC in

  1. A Transversely Isotropic Thermo-mechanical Framework for Oil Shale

    Semnani, S. J.; White, J. A.; Borja, R. I.

    2014-12-01

    The present study provides a thermo-mechanical framework for modeling the temperature dependent behavior of oil shale. As a result of heating, oil shale undergoes phase transformations, during which organic matter is converted to petroleum products, e.g. light oil, heavy oil, bitumen, and coke. The change in the constituents and microstructure of shale at high temperatures dramatically alters its mechanical behavior e.g. plastic deformations and strength, as demonstrated by triaxial tests conducted at multiple temperatures [1,2]. Accordingly, the present model formulates the effects of changes in the chemical constituents due to thermal loading. It is well known that due to the layered structure of shale its mechanical properties in the direction parallel to the bedding planes is significantly different from its properties in the perpendicular direction. Although isotropic models simplify the modeling process, they fail to accurately describe the mechanical behavior of these rocks. Therefore, many researchers have studied the anisotropic behavior of rocks, including shale [3]. The current study presents a framework to incorporate the effects of transverse isotropy within a thermo-mechanical formulation. The proposed constitutive model can be readily applied to existing finite element codes to predict the behavior of oil shale in applications such as in-situ retorting process and stability assessment in petroleum reservoirs. [1] Masri, M. et al."Experimental Study of the Thermomechanical Behavior of the Petroleum Reservoir." SPE Eastern Regional/AAPG Eastern Section Joint Meeting. Society of Petroleum Engineers, 2008. [2] Xu, B. et al. "Thermal impact on shale deformation/failure behaviors---laboratory studies." 45th US Rock Mechanics/Geomechanics Symposium. American Rock Mechanics Association, 2011. [3] Crook, AJL et al. "Development of an orthotropic 3D elastoplastic material model for shale." SPE/ISRM Rock Mechanics Conference. Society of Petroleum Engineers

  2. Application of python-based Abaqus preprocess and postprocess technique in analysis of gearbox vibration and noise reduction

    Yi, Guilian; Sui, Yunkang; Du, Jiazheng

    2011-06-01

    To reduce vibration and noise, a damping layer and constraint layer are usually pasted on the inner surface of a gearbox thin shell, and their thicknesses are the main parameters in the vibration and noise reduction design. The normal acceleration of the point on the gearbox surface is the main index that can reflect the vibration and noise of that point, and the normal accelerations of different points can reflect the degree of the vibration and noise of the whole structure. The K-S function is adopted to process many points' normal accelerations as the comprehensive index of the vibration characteristics of the whole structure, and the vibration acceleration level is adopted to measure the degree of the vibration and noise. Secondary development of the Abaqus preprocess and postprocess on the basis of the Python scripting programming automatically modifies the model parameters, submits the job, and restarts the analysis totally, which avoids the tedious work of returning to the Abaqus/CAE for modifying and resubmitting and improves the speed of the preprocess and postprocess and the computational efficiency.

  3. Drift-scale thermomechanical analysis for the retrievability systems study

    Tsai, F.C. [M& O/Woodward Clyde Federal Services, Las Vegas, NV (United States)

    1996-04-01

    A numerical method was used to estimate the stability of potential emplacement drifts without considering a ground support system as a part of the Thermal Loading Systems Study for the Yucca Mountain Site Characterization Project. The stability of the drift is evaluated with two variables: the level of thermal loading and the diameter of the emplacement drift. The analyses include the thermomechanical effects generated by the excavation of the drift, subsequently by the thermal loads from heat-emitting waste packages, and finally by the thermal reduction resulting from rapid cooling ventilation required for the waste retrieval if required. The Discontinuous Deformation Analysis (DDA) code was used to analyze the thermomechanical response of the rock mass of multiple blocks separated by joints. The result of this stability analysis is used to discuss the geomechanical considerations for the advanced conceptual design (ACD) with respect to retrievability. In particular, based on the rock mass strength of the host rock described in the current version of the Reference Information Base, the computed thermal stresses, generated by 111 MTU/acre thermal loads in the near field at 100 years after waste emplacement, is beyond the criterion for the rock mass strength used to predict the stability of the rock mass surrounding the emplacement drift.

  4. Thermomechanical treatment of heat-resisting alloys

    Different types of thermomechanical treatment (TMT) are considered in the review. Three schemes which are used for heat resistant ageing alloys are singled out and described in detail: high-temperature thermomechanical treatment (HTMT), mechanico-thermal treatment (MTT) and low-temperature thermomechanical treatment (LTMT). Special attention is paid to perspective LTMT including warm deformation. It is shown that the application of the TMT to concrete alloys permits to increase the strength characteristics in a certain temperature range of the product exploitation without considerable plasticity loss. TMT with the use.of warm deformation in two-phase region looks like the most perspective treatment increasing strength properties, resistance against fatigue destruction and decreasing the sensitivity to the cut

  5. Numerical modeling and prediction of thermomechanical degradation of power electronic packaging

    Baazaoui, Ahlem; Dalverny, Olivier; Alexis, Joël; Karama, Moussa

    2013-01-01

    This work aims at numerical thermomechanical studies of two types of high temperature silver connections elaborated at low temperatures, the transient liquid phase bonding (TLPB) of Ag-In and silver nanoparticles sintering, using test vehicles representing the final packaging assemblies of diamond components. The simulation is performed using a finite element code on 2D and 3D assemblies. The stress distribution in the assemblies and in the two die-attachments was studied during thermal cycli...

  6. 基于ABAQUS的连杆疲劳分析%Fatigue Analysis of Connecting Rods Based on ABAQUS

    谈梅兰; 武国玉; 梁福祥

    2013-01-01

    为了全面地考察连杆受到的动态疲劳载荷,在发动机标定工况下,利用转动惯量法对连杆进行了运动学和动力学分析.基于临界平面法,用ABAQUS软件进行二次开发得到了连杆的疲劳计算模块.采用有限元方法分析计算了连杆的疲劳寿命.整个过程是在ABAQUS软件中用Python语言编程来实现的.数值计算结果显示,与传统的最大拉压工况结果相比,在发动机标定工况下得到的计算结果能比较全面地反映连杆的疲劳特性,表明该数值计算方法正确,二次开发程序可行.%In order to investigate the dynamic fatigue loads of a connecting rod under engine calibration conditions more fully, the analysis of kinematics and dynamics of the connecting rod was carried out using the rotational inertia method. With the help of the critical plane method, fatigue calculation module was redeveloped based on ABAQUS. The fatigue life was given through finite element analysis of the connecting rod. The whole process was achieved by Python programming language in the ABAQUS software. The developed method herein is able to reflect the connecting rod's fatigue properties more fully by the comparison of numerical results obtained in the engine calibration conditions with the traditional results of the maximum tensile and compressive conditions. It is also shown that the numerical calculation is correct, the redevelopment of the program is feasible.

  7. Multiscale thermomechanical analysis of multiphase materials

    Yadegari Varnamkhasti, S.

    2015-01-01

    The thermomechanical simulation of materials with evolving, multiphase microstructures poses various modeling and numerical challenges. For example, the separate phases in a multiphase microstructure can interact with each other during thermal and/or mechanical loading, the effect of which is signif

  8. Introduction to nonlinear thermomechanics of solids

    Kleiber, Michał

    2016-01-01

    The first part of this textbook presents the mathematical background needed to precisely describe the basic problem of continuum thermomechanics. The book then concentrates on developing governing equations for the problem dealing in turn with the kinematics of material continuum, description of the state of stress, discussion of the fundamental conservation laws of underlying physics, formulation of initial-boundary value problems and presenting weak (variational) formulations. In the final part the crucial issue of developing techniques for solving specific problems of thermomechanics is addressed. To this aim the authors present a discretized formulation of the governing equations, discuss the fundamentals of the finite element method and develop some basic algorithms for solving algebraic and ordinary differential equations typical of problems on hand. Theoretical derivations are followed by carefully prepared computational exercises and solutions.

  9. FGM elastoplastic analysis under thermomechanical loading

    In this research, thick walled FGM spherical pressure vessels under internal pressure and temperature difference were studied. Material parameters were considered to vary as a power functions. In order to clarify the role of material parameters, several different materials with different parameters have been used. Different combinations of the internal pressure and temperature gradient loading were applied and their effects on the yield onset location, kinds of stresses and the role of temperature gradient, were studied. Linear kinematic hardening was supposed and the pressure vessel behavior under constant internal; pressure and cyclic temperature gradient, was obtained. -- Highlights: • Elastic solution of an FGM spherical pressure vessel under thermomechanical loading was obtained. • Yield onset under different thermomechanical loading and material properties were obtained. • Linear kinematic hardening was used and plastic strain and stress equations were developed. • Bree's interaction diagram was obtained for two different FGM pressure vessel

  10. Thermomechanics of composite structures under high temperatures

    Dimitrienko, Yu I

    2016-01-01

    This pioneering book presents new models for the thermomechanical behavior of composite materials and structures taking into account internal physico-chemical transformations such as thermodecomposition, sublimation and melting at high temperatures (up to 3000 K). It is of great importance for the design of new thermostable materials and for the investigation of reliability and fire safety of composite structures. It also supports the investigation of interaction of composites with laser irradiation and the design of heat-shield systems. Structural methods are presented for calculating the effective mechanical and thermal properties of matrices, fibres and unidirectional, reinforced by dispersed particles and textile composites, in terms of properties of their constituent phases. Useful calculation methods are developed for characteristics such as the rate of thermomechanical erosion of composites under high-speed flow and the heat deformation of composites with account of chemical shrinkage. The author expan...

  11. Thermomechanical Stresses in Fullerenes at Nanotube

    Pugno, Nicola M.

    2008-01-01

    The thermomechanical stresses acting between a nanotube and fullerenes encapsulated on it are computed. After a general formulation, based on elasticity, we have applied the analysis to C82000040(10,10) or C60000040(10,10) peapods finding stresses in the gigapascal range or vanishing, respectively. The analysis suggests that a thermal control could be used to produce smart fullerenes at nanotube systems, for example, as two-stage nanovectors for drug delivery.

  12. Thermomechanical Stresses in Fullerenes at Nanotube

    Nicola M. Pugno

    2008-01-01

    Full Text Available The thermomechanical stresses acting between a nanotube and fullerenes encapsulated on it are computed. After a general formulation, based on elasticity, we have applied the analysis to C82000040(10,10 or C60000040(10,10 peapods finding stresses in the gigapascal range or vanishing, respectively. The analysis suggests that a thermal control could be used to produce smart fullerenes at nanotube systems, for example, as two-stage nanovectors for drug delivery.

  13. 基于Abaqus/explicit的钛合金高速切削切削力模拟研究%Simulation Study on Cutting Force During High Speed Machining Titanium Alloy Based on Abaqus/explicit

    芮执元; 李川平; 郭俊锋; 冯瑞成

    2011-01-01

    The aim of this research was to investigate cutting force during high speed machining titanium alloy. Johnson- Cook materials model and fracture criterion of commercial finite element software Abaqus was used to simulate high speed machining Ti6Al4V. It was Analyzed that The influence of the cutting parameters (including feed rate, cutting depth, cutting speed) on the cutting forces. The results shown that cutting force, feed force, specific cutting force and specific feed force reduced with increases in cutting speed, cutting force, feed force increased and specific cutting force, specific feed force reduced with increases in feed rate.%针对高速切削钛合金时切削力的问题,利用有限元分析软件Abaqus的Johnson-Cook材料模型及Johnson-Cook断裂准则,对钛合金高速切削切削力进行了仿真研究,分析钛合金高速切削加工过程中各切削参数(包括进给量、切削深度和切削速度)对切削力的影响.结果表明,切削力、进给力、单位面积切削力和单位面积进给力都随速度的增大而减小;但随着进给速度的增大,切削力和进给力都增大,而单位面积的切削力和进给力都减小.

  14. Thermomechanical evaluation of the fuel assemblies fabricated in the ININ; Evaluacion termomecanica de los ensambles combustibles fabricados en el ININ

    Hernandez L, H.; Ortiz V, J. [ININ, 52045 Ocoyoacac, Estado de Mexico (Mexico)

    2005-07-01

    The pilot plant of fuel production of the National Institute of Nuclear Research (ININ) provided to the Laguna Verde Nuclear Power Plant (CNLV) four fuel assemblies type GE9B. The fuel irradiation was carried out in the unit 1 of the CNLV during four operation cycles, highlighting the fact that in their third cycle the four assemblies were placed in the center of the reactor core. In the Nuclear Systems Department (DSN) of the ININ it has been carried out studies to evaluate their neutron performance and to be able to determine the exposure levels of this fuels. Its also outlines the necessity to carry out a study of the thermomechanical behavior of the fuel rods that compose the assemblies, through computational codes that simulate their performance so much thermal as mechanical. For such purpose has been developing in the DSN the FETMA code, together with the codes that compose the system Fuel Management System (FMS), which evaluates the thermomechanical performance of fuel elements. In this work were used the FETMA and FEMAXI codes (developed by JAERI) to study the thermomechanical performance of the fuel elements manufactured in the ININ. (Author)

  15. Theoretical approach to the WWER core thermomechanical modelling

    The paper presents studies on the analysis of root causes of fuel assembly bowing under operating conditions; developing of a methodology for fuel assemblies thermomechanical simulation; developing of a calculation technique for thermomechanical modelling of the fuel assemblies bowing in operational conditions. Some examples of calculation results are given

  16. Thermomechanical Properties of TiNi Shape Memory Alloy

    Tobushi, H.; Ikai, A; Yamada, S.; K.Tanaka; Lexcellent, C.

    1996-01-01

    The thermomechanical properties of shape memory effect and superelasticity due to the martensitic transformation and the R-phase transformation of TiNi shape memory alloy were investigated experimentally. The transformation Une, recovery stress and fatigue property due to both transformations were discussed for cyclic deformation. The thermomechanical properties due to the R-phase transformation were excellent for deformation with high cycles.

  17. Interfacing VPSC with finite element codes. Demonstration of irradiation growth simulation in a cladding tube

    Patra, Anirban [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Tome, Carlos [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

    2016-03-23

    This Milestone report shows good progress in interfacing VPSC with the FE codes ABAQUS and MOOSE, to perform component-level simulations of irradiation-induced deformation in Zirconium alloys. In this preliminary application, we have performed an irradiation growth simulation in the quarter geometry of a cladding tube. We have benchmarked VPSC-ABAQUS and VPSC-MOOSE predictions with VPSC-SA predictions to verify the accuracy of the VPSCFE interface. Predictions from the FE simulations are in general agreement with VPSC-SA simulations and also with experimental trends.

  18. Interfacing VPSC with finite element codes. Demonstration of irradiation growth simulation in a cladding tube

    This Milestone report shows good progress in interfacing VPSC with the FE codes ABAQUS and MOOSE, to perform component-level simulations of irradiation-induced deformation in Zirconium alloys. In this preliminary application, we have performed an irradiation growth simulation in the quarter geometry of a cladding tube. We have benchmarked VPSC-ABAQUS and VPSC-MOOSE predictions with VPSC-SA predictions to verify the accuracy of the VPSCFE interface. Predictions from the FE simulations are in general agreement with VPSC-SA simulations and also with experimental trends.

  19. Coupling of STOMP and ABAQUS for Hydro-Geomechanical Modeling of Fluid Flow and Rock Deformation Associated with Subsurface CO2 Injection

    Carroll, K. C.; Nguyen, B. N.; Fang, Y.; Richmond, M. C.; Murray, C. J.

    2011-12-01

    Geomechanical alteration of porous media is generally ignored for most shallow subsurface applications, whereas CO2 injection, migration, and trapping in deep saline aquifers will be controlled by coupled multifluid flow, energy transfer, geomechanical, and geochemical processes. The accurate assessment of the risks associated with potential leakage of injected CO2 and the design of effective injection systems requires that we represent these coupled processes within numerical simulators. The objective of this study was to examine the coupling of hydraulic and geomechanical processes for simulation of CO2 injection into the subsurface for carbon sequestration. The impact of nonisothermal multifluid flow and porous media deformation mechanics on CO2 migration and storage was evaluated. We present a sequentially coupled approach for multifluid and geomechanical simulation using STOMP and ABAQUS that has been developed and validated through comparison to the solutions for benchmark problems that were solved with a coupled TOUGH-FLAC simulator. The poroelastic model was implemented with user-subroutines in ABAQUS. We also compare the STOMP-ABAQUS simulator to a new version of STOMP that includes the fully coupled poroelastic simulation within the multifluid flow and transport simulator. The poroelastic model computes stiffness, stresses, and strains using aqueous and gas pressures as well as saturations from STOMP output, and provides STOMP with the updated permeability, porosity, and capillary pressure over time during the simulation. The hydraulic only (uncoupled from mechanics) simulation and the hydrogeomechanical (coupled) simulation results using STOMP-ABAQUS were comparable to the previous results of a TOUGH-FLAC simulator. Results from the STOMP-ABAQUS coupled simulator were essentially identical to the fully coupled STOMP hydrogeomechanical simulator when the sequential coupling occurred at small time steps, and deviations between results increased with

  20. Start-up and shutdown thermomechanical transient analyses of the IFMIF European lithium target system

    In the framework of the current IFMIF Engineering Validation and Engineering Design Activities (IFMIF/EVEDA) phase, ENEA is responsible for the design of the European concept of the IFMIF lithium target system which foresees the possibility to periodically replace only the most irradiated and thus critical component (i.e., the backplate) while continuing to operate the rest of the target for a longer period (bayonet backplate concept). With the objective of evaluating the performances of the system in terms of temperature, stress and displacement fields evolution during start-up and shutdown phases, an uncoupled thermomechanical transient analysis has been performed in close collaboration with the University of Palermo by means of a qualified finite element (FE) thermomechanical code. The calculations employed a realistic 3D time-dependent FE model which takes into account all the mechanical and thermal loads including the nuclear heating due to neutron and prompt gamma fields during start-up and decay power of activated products during shutdown. The nuclear data have been calculated by ENEA as part of a parallel extensive neutronic analysis carried out through the MCNP transport code and the EASY-2010 activation code package and then passed as input to the thermomechanical FE model. In this paper, the results of the above transient analyses are reported, highlighting the relevant indications obtained with respect to the fulfillment of the design requirements and possible hints for improving the system design. In particular, it is found that ITER design rules taking into account secondary loads are not always fulfilled during the transient, whereas the predicted displacements allow to exclude any contact of the target system with the surrounding structures

  1. A thermo mechanical benchmark calculation of a hexagonal can in the BTI accident with INCA code

    The thermomechanical behaviour of an hexagonal can in a benchmark problem (simulating the conditions of a BTI accident in a fuel assembly) is examined by means of the INCA code and the results systematically compared with those of ADINA

  2. Thermomechanical behavior of dry contacts in disc brake rotor with a grey cast iron composition

    Belhocine Ali

    2013-01-01

    Full Text Available The main purpose of this study is to analysis the thermomechanical behavior of the dry contact between the brake disc and pads during the braking phase. The simulation strategy is based on the calculation code ANSYS11. The modeling of transient temperature in the disk is actually used to identify the factor of geometric design of the disk to install the ventilation system in vehicles. The thermal-structural analysis is then used coupling to determine the deformation established and the Von Mises stresses in the disk, the contact pressure distribution in pads. The results are satisfactory compared to those found in the literature.

  3. Thermomechanically-controlled Processing for Producing Ship-building Steels

    B. Basu

    2005-01-01

    Full Text Available The thermomechanically-controlled processing of a newly developed high-strength lowalloy steel has been designed in such a way that the problems, normally faced in producing thequench and tempered steels, have been mitigated and the final product (steel plates are available in as rolled condition rather than quench and tempered steels.A low-carbon, low-alloy steel having nickel, chromium, copper, niobium, boron, has been designed for ease of welding, improved weldability over the conventional steels, and responsiveto the thermomechanically-controlled processing. A number of laboratory-scale batches of the alloy were made with different combinations of thermomechanically-controlled processingparameters. The different thermomechanically-controlled processing parameters studied include (i slab-reheating temperature,~ (ii. def.orm ation above recrvstallisation temperature, (iiideformation below recrystallisation temperature, and (iv finish-rolling temperature. The thermomechanically-processed steel plates, under certain combinations of  thermomechanically-controlled ~rocessi-ne.o arameters. showed excellent combination of imvact and tensile n.r on. erties. In this paper, the microstructure-property correlation has been made to throw light on the type of microstructure required to obtain such superior package of mechanical properties. Further, the optimised laboratory-scale thermomechanically-controlled processing parameters, which were used to process newer hatches of the steel made through industrial route, have delivered encouraging results.

  4. Thermo-mechanical ratcheting in jointed rock masses

    Pasten, C.

    2015-09-01

    Thermo-mechanical coupling takes place in jointed rock masses subjected to large thermal oscillations. Examples range from exposed surfaces under daily and seasonal thermal fluctuations to subsurface rock masses affected by engineered systems such as geothermal operations. Experimental, numerical and analytical results show that thermo-mechanical coupling can lead to wedging and ratcheting mechanisms that result in deformation accumulation when the rock mass is subjected to a biased static-force condition. Analytical and numerical models help in identifying the parameter domain where thermo-mechanical ratcheting can take place.

  5. Thermomechanic micro-generators for energy harvesting

    Huesgen, Till

    2010-07-01

    This work, in contrast, focuses on the development of a novel thermomechanic generator based on a dynamic micro engine. The engine is fabricated on a chip-scale in silicon technology and is unique regarding its size and properties. A closed engine chamber, filled with a working fluid, performs a reciprocating motion between a heat source and a heat sink. Thereby, the engine operates passively hence it is self starting and the operation frequency depends on the applied temperature difference. Primary goals of this work are the design of the engine and an experimental proof-of-concent. A hybrid model composed of a FEM simulation for the membrane mechanics, analytical calculations of the thermodynamic cycle, and a thermal network model, allows to theoretically investigate the engine performance. The relevant benchmarks are the operation frequency, mechanical output power and the thermal resistance of the engine. Using this model, an exemplary optimization of the engine geometry is conducted with respect to a high efficiency. In this case, a theoretical optimum of 28.3 x 10{sup -4}% is found for the thermomechanic energy conversion. The experimental part focuses on the fabrication and characterization of a not optimized demonstrator engine. Two different types of working fluid are applied, either air or an organic coolant. The maximum measured operation frequency is 1.2 Hz at 100 K temperature difference for the air-filled engine and 0.75 Hy at 37 K temperature difference for the engine filled with the organic coolant. A maximum velocity of 0.061 m/sec and -0.031 m/sec is measured for the upward and downward motion. These experimental data yield a maximum mechanical output power of 0.5 {mu}W for the air-filled engine and 0.26 {mu}W for the engine filled with the organic coolant. The integration of an electric generator provides a further task. Two fundamentally different approaches have been investigated. The first approach is based on an electromagnetic conversion of

  6. Instrumentation requirements for the ESF thermomechanical experiments

    Pott, J. [Sandia National Labs., Albuquerque, NM (United States); Brechtel, C.E. [Agapito (J.F.T.) and Associates, Inc., Grand Junction, CO (United States)

    1992-12-31

    In situ thermomechanical experiments are planned as part of the Yucca Mountain Site Characterization Project that require instruments to measure stress and displacement at temperatures that exceed the typical specifications of existing geotechnical instruments. A high degree of instrument reliability will also be required to satisfy the objectives of the experiments, therefore a study was undertaken to identify areas where improvement in instrument performance was required. A preliminary list of instruments required for the experiments was developed, based on existing test planning and analysis. Projected temperature requirements were compared to specifications of existing instruments to identify instrumentation development needs. Different instrument technologies, not currently employed in geotechnical instrumentation, were reviewed to identify potential improvements of existing designs for the high temperature environment. Technologies with strong potentials to improve instrument performance with relatively high reliability include graphite fiber composite materials, fiber optics, and video imagery.

  7. Instrumentation requirements for the ESF thermomechanical experiments

    In situ thermomechanical experiments are planned as part of the Yucca Mountain Site Characterization Project that require instruments to measure stress and displacement at temperatures that exceed the typical specifications of existing geotechnical instruments. A high degree of instrument reliability will also be required to satisfy the objectives of the experiments, therefore a study was undertaken to identify areas where improvement in instrument performance was required. A preliminary list of instruments required for the experiments was developed, based on existing test planning and analysis. Projected temperature requirements were compared to specifications of existing instruments to identify instrumentation development needs. Different instrument technologies, not currently employed in geotechnical instrumentation, were reviewed to identify potential improvements of existing designs for the high temperature environment. Technologies with strong potentials to improve instrument performance with relatively high reliability include graphite fiber composite materials, fiber optics, and video imagery

  8. Thermomechanical studies in granite at Stripa, Sweden

    Media other than rock salt are being considered for the deep, geologic disposal of nuclear wastes. The disposal of high-level nuclear waste in a deep, underground repository will subject the rock to a thermal pulse that will induce displacements, strains, and stresses in the rock. Thermomechanical experiments, with electrical heaters simulating the thermal output of waste canisters, were carried out in granite at a depth of 340 m below surface adjacent to a defunct iron ore mine at Stripa, Sweden. Changes in temperature, displacement, and stress in the rock around these heaters were measured, and the measurements were compared with predictions calculated from the theory of linear thermoelasticity. Measured temperature changes agreed well with predictions, but measured displacements and stresses were consistently less than those predicted with constant values for the coefficient of thermal expansion and elastic properties of the rock. A laboratory test program to measure these coefficients over ranges of stress and temperature representing those in the field experiment has been initiated. Test specimens were taken from cores recovered from the instrumentation holes in the Stripa experiments. Preliminary results from laboratory tests on specimens free of joints indicate that the values of Young's modulus and Poisson's ratio increase from about 60 to 80 MPa and from 0.15 to 0.22, respectively, as the confining stress is increased from 2 to 55 MPa; these values decrease with increasing temperature, more so at 2 MPa than at 55 MPa. The linear coefficient of thermal expansion at a confining stress of 30 MPa increases from about 10 x 10-6/0C at 400C to about 14 x 10-6/0C. The magnitudes of these changes are not sufficient to resolve the disparity between measured and predicted results. Perhaps the properties of test specimens containing joints will show greater variations in the values of the thermomechanical coefficients with temperature and pressure

  9. Interactive evolution concept for analyzing a rock salt cavern under cyclic thermo-mechanical loading

    König, Diethard; Mahmoudi, Elham; Khaledi, Kavan; von Blumenthal, Achim; Schanz, Tom

    2016-04-01

    The excess electricity produced by renewable energy sources available during off-peak periods of consumption can be used e.g. to produce and compress hydrogen or to compress air. Afterwards the pressurized gas is stored in the rock salt cavities. During this process, thermo-mechanical cyclic loading is applied to the rock salt surrounding the cavern. Compared to the operation of conventional storage caverns in rock salt the frequencies of filling and discharging cycles and therefore the thermo-mechanical loading cycles are much higher, e.g. daily or weekly compared to seasonally or yearly. The stress strain behavior of rock salt as well as the deformation behavior and the stability of caverns in rock salt under such loading conditions are unknown. To overcome this, existing experimental studies have to be supplemented by exploring the behavior of rock salt under combined thermo-mechanical cyclic loading. Existing constitutive relations have to be extended to cover degradation of rock salt under thermo-mechanical cyclic loading. At least the complex system of a cavern in rock salt under these loading conditions has to be analyzed by numerical modeling taking into account the uncertainties due to limited access in large depth to investigate material composition and properties. An interactive evolution concept is presented to link the different components of such a study - experimental modeling, constitutive modeling and numerical modeling. A triaxial experimental setup is designed to characterize the cyclic thermo-mechanical behavior of rock salt. The imposed boundary conditions in the experimental setup are assumed to be similar to the stress state obtained from a full-scale numerical simulation. The computational model relies primarily on the governing constitutive model for predicting the behavior of rock salt cavity. Hence, a sophisticated elasto-viscoplastic creep constitutive model is developed to take into account the dilatancy and damage progress, as well as

  10. EXPERIENCE WITH THERMOMECHANICAL FATIGUE UNDER SERVICE-TYPE LOADING

    A.Scholz; A.Schmidt; A.Samir; C.Berger

    2004-01-01

    The thermomechanical fatigue behaviour of different high temperature alloys has been investigated and is under investigation respectively. The creep-fatigue behaviour of heat resistant steels was investigated by long-term service-type strain cycling tests simulating thermomechanical fatigue (TMF-) loading conditions at the heated surface of e.g. turbine rotors. Single-stage as well as three-stage cycles leads to similar results at the application of the damage accumulation rule. Life prediction which simulates typical combinations of cold starts, warm starts and hot starts has been established successfully for isothermal service-type loading and will be exceeded for thermomechanical loading. Long-term thermomechanical fatigue testing of Thermal Barrier Coating systems show typical delamination damage. An advanced TMF cruciform testing system enables complex multiaxial loading.

  11. Thermo-mechanical analysis of an SI engine piston using different boundary condition treatments

    Amir-Hasan Kakaee; Javad Gharloghi; Aliasghar Foroughifar; Abdoreza Khanlari

    2015-01-01

    Heat transfer of an SI engine’s piston is calculated by employing three different methods based on resistor-capacitor model with the help of MATLAB code, and then the piston is thermo-mechanically analyzed using commercial ANSYS code. The results of three methods are compared to study their effects on the piston thermal behavior. It is shown that resistor−capacitor model with less number of equations and consequently less solution time, is an appropriate method for solving problems of engine piston heat transfer. In the second part, the thermal stresses due to non-uniform temperature distribution, and mechanical stresses due to mechanical loads are calculated. Finally, the temperature distributions as a thermal load along with mechanical loads are applied to the piston to determine the total stress distribution and critical fracture zones. It is found that the amount of thermal stresses is considerable.

  12. Modeling of the thermo-mechanical behaviour of the PWR fuel

    This article reviews the various physical phenomena that take place in an irradiated fuel rod and presents the development of the thermo-mechanical codes able to simulate them. Though technically simple the fuel rod is the place where appear 4 types of process: thermal, gas behaviour, mechanical and corrosion that combine involving 5 elements: the fuel pellet, the fuel clad, the fuel-clad gap, the inside volume and the coolant. For instance the pellet is the place where the following mechanical processes took place: thermal dilatation, elastic deformation, creep deformation, densification, solid swelling, gaseous swelling and cracking. The first industrial code simulating the behaviour of the fuel rod was COCCINEL, it was developed by AREVA teams from the American PAD code that was included in the Westinghouse license. Today the GALILEO code has replaced the COPERNIC code that was developed in the beginning of the 2000 years. GALILEO is a synthesis of the state of the art of the different models used in the codes validated for PWR and BWR. GALILEO has been validated on more than 1500 fuel rods concerning PWR, BWR and specific reactors like Siloe, Osiris, HFR, Halden, Studsvik, BR2/3,...) and also for extended burn-ups. (A.C.)

  13. Safety assessment of nuclear power plant pipelines against thermo-mechanical fatigue in the presence of hybrid uncertainties

    Power plant piping components are subjected to a variety of thermal and thermo-mechanical loads, which include loads during hot shut down and cold shut down, in addition to the normal or steady operating loads of the power plant. A large number of piping failures in Pressurized Heavy Water reactors in the form of cracks and leaks due to these thermo-mechanical loads have been reported. Thermomechanical fatigue is one of the primary life-limiting factors for piping components in high temperature applications. In this paper, a procedure for the safety assessment of a nuclear power plant piping component against thermomechanical fatigue, by treating the relevant uncertain variables as random or fuzzy depending upon the source of uncertainty, is proposed. The fuzzy failure probabilities are computed using the method developed at CSIR-SERC, combining the vertex method with Monte Carlo simulation technique. The strain-based approach, which is the general approach employed for continuum response in safe-life, finite-life region i.e., the low cycle fatigue region with stabilized cyclic stress-strain constants, is used in the safety assessment. An example of a main steam piping of an operating thermal power plant is considered for illustrating the safety assessment procedure. It is also noted that one can determine the bounds for failure probability from the resulting fuzzy set for failure probability with minimal computational effort. The proposed procedure will help in rationally taking into account various uncertainties while designing the components with known/acceptable levels of safety specified either in codes or by learned bodies (AERB codes/NUREG). (author)

  14. Thermomechanical fatigue in single crystal superalloys

    Moverare Johan J.

    2014-01-01

    Full Text Available Thermomechanical fatigue (TMF is a mechanism of deformation which is growing in importance due to the efficiency of modern cooling systems and the manner in which turbines and associated turbomachinery are now being operated. Unfortunately, at the present time, relatively little research has been carried out particularly on TMF of single crystal (SX superalloys, probably because the testing is significantly more challenging than the more standard creep and low cycle fatigue (LCF cases; the scarcity and relative expense of the material are additional factors. In this paper, the authors summarise their experiences on the TMF testing of SX superalloys, built up over several years. Emphasis is placed upon describing: (i the nature of the testing method, the challenges involved in ensuring that an given testing methodology is representative of engine conditions (ii the behaviour of a typical Re-containing second generation alloy such as CMSX-4, and its differing performance in out-of-phase/in-phase loading and crystallographic orientation and (iii the differences in behaviour displayed by the Re-containing alloys and new Re-free variants such as STAL15. It is demonstrated that the Re-containing superalloys are prone to different degradation mechanisms involving for example microtwinning, TCP precipitation and recrystallisation. The performance of STAL15 is not too inferior to alloys such as CMSX-4, suggesting that creep resistance itself does not correlate strongly with resistance to TMF. The implications for alloy design efforts are discussed.

  15. Thermo-mechanical characterization of silicone foams

    Rangaswamy, Partha [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Smith, Nickolaus A. [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Cady, Carl M. [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Lewis, Matthew W. [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

    2015-10-01

    Cellular solids such as elastomeric foams are used in many structural applications to absorb and dissipate energy, due to their light weight (low density) and high energy absorption capability. In this paper we will discuss foams derived from S5370, a silicone foam formulation developed by Dow Corning. In the application presented, the foam is consolidated into a cushion component of constant thickness but variable density. A mechanical material model developed by Lewis (2013), predicts material response, in part, as a function of relative density. To determine the required parameters for this model we have obtained the mechanical response in compression for ambient, cold and hot temperatures. The variable density cushion provided samples sufficient samples so that the effect of sample initial density on the mechanical response could be studied. The mechanical response data showed extreme sensitivity to relative density. We also observed at strains corresponding to 1 MPa a linear relationship between strain and initial density for all temperatures. Samples taken from parts with a history of thermal cycling demonstrated a stiffening response that was a function of temperature, with the trend of more stiffness as temperature increased above ambient. This observation is in agreement with the entropic effects on the thermo-mechanical behavior of silicone polymers. In this study, we present the experimental methods necessary for the development of a material model, the testing protocol, analysis of test data, and a discussion of load (stress) and gap (strain) as a function of sample initial densities and temperatures

  16. Thermomechanical evaluation of BWR fuel elements for procedures of preconditioned with FEMAXI-V

    The limitations in the burnt of the nuclear fuel usually are fixed by the one limit in the efforts to that undergo them the components of a nuclear fuel assembly. The limits defined its provide the direction to the fuel designer to reduce to the minimum the fuel failure during the operation, and they also prevent against some thermomechanical phenomena that could happen during the evolution of transitory events. Particularly, a limit value of LHGR is fixed to consider those physical phenomena that could lead to the interaction of the pellet-shirt (Pellet Cladding Interaction, PCI). This limit value it is related directly with an PCI limit that can be fixed based on experimental tests of power ramps. This way, to avoid to violate the PCI limit, the conditioning procedures of the fuel are still required for fuel elements with and without barrier. Those simulation procedures of the power ramp are carried out for the reactor operator during the starting maneuvers or of power increase like preventive measure of possible consequences in the thermomechanical behavior of the fuel. In this work, the thermomechanical behavior of two different types of fuel rods of the boiling water reactor is analyzed during the pursuit of the procedures of fuel preconditioning. Five diverse preconditioning calculations were carried out, each one with three diverse linear ramps of power increments. The starting point of the ramps was taken of the data of the cycle 8 of the unit 1 of the Laguna Verde Nucleo electric Central. The superior limit superior of the ramps it was the threshold of the lineal power in which a fuel failure could be presented by PCI, in function of the fuel burnt. The analysis was carried out with the FEMAXI-V code. (Author)

  17. 3-D Numerical Simulation and Analysis of Complex Fiber Geometry RaFC Materials with High Volume Fraction and High Aspect Ratio based on ABAQUS PYTHON

    Jin, BoCheng

    2011-12-01

    Organic and inorganic fiber reinforced composites with innumerable fiber orientation distributions and fiber geometries are abundantly available in several natural and synthetic structures. Inorganic glass fiber composites have been introduced to numerous applications due to their economical fabrication and tailored structural properties. Numerical characterization of such composite material systems is necessitated due to their intrinsic statistical nature, which renders extensive experimentation prohibitively time consuming and costly. To predict various mechanical behavior and characterizations of Uni-Directional Fiber Composites (UDFC) and Random Fiber Composites (RaFC), we numerically developed Representative Volume Elements (RVE) with high accuracy and efficiency and with complex fiber geometric representations encountered in uni-directional and random fiber networks. In this thesis, the numerical simulations of unidirectional RaFC fiber strand RVE models (VF>70%) are first presented by programming in ABAQUS PYTHON. Secondly, when the cross sectional aspect ratios (AR) of the second phase fiber inclusions are not necessarily one, various types of RVE models with different cross sectional shape fibers are simulated and discussed. A modified random sequential absorption algorithm is applied to enhance the volume fraction number (VF) of the RVE, which the mechanical properties represents the composite material. Thirdly, based on a Spatial Segment Shortest Distance (SSSD) algorithm, a 3-Dimentional RaFC material RVE model is simulated in ABAQUS PYTHON with randomly oriented and distributed straight fibers of high fiber aspect ratio (AR=100:1) and volume fraction (VF=31.8%). Fourthly, the piecewise multi-segments fiber geometry is obtained in MATLAB environment by a modified SSSD algorithm. Finally, numerical methods including the polynomial curve fitting and piecewise quadratic and cubic B-spline interpolation are applied to optimize the RaFC fiber geometries

  18. FY15 Report on Thermomechanical Testing

    Hansen, Francis D. [Sandia National Laboratories (SNL-NM), Albuquerque, NM (United States); Buchholz, Stuart [RESPEC, Rapid City, SD (United States)

    2015-08-01

    Sandia is participating in the third phase of a United States (US)-German Joint Project that compares constitutive models and simulation procedures on the basis of model calculations of the thermomechanical behavior and healing of rock salt (Salzer et al. 2015). The first goal of the project is to evaluate the ability of numerical modeling tools to correctly describe the relevant deformation phenomena in rock salt under various influences. Among the numerical modeling tools required to address this are constitutive models that are used in computer simulations for the description of the thermal, mechanical, and hydraulic behavior of the host rock under various influences and for the long-term prediction of this behavior. Achieving this goal will lead to increased confidence in the results of numerical simulations related to the secure disposal of radioactive wastes in rock salt. Results of the Joint Project may ultimately be used to make various assertions regarding stability analysis of an underground repository in salt during the operating phase as well as long-term integrity of the geological barrier in the post-operating phase A primary evaluation of constitutive model capabilities comes by way of predicting large-scale field tests. The Joint Project partners decided to model Waste Isolation Pilot Plant (WIPP) Rooms B & D which are full-scale rooms having the same dimensions. Room D deformed under natural, ambient conditions while Room B was thermally driven by an array of waste-simulating heaters (Munson et al. 1988; 1990). Existing laboratory test data for WIPP salt were carefully scrutinized and the partners decided that additional testing would be needed to help evaluate advanced features of the constitutive models. The German partners performed over 140 laboratory tests on WIPP salt at no charge to the US Department of Energy (DOE).

  19. Parametric study of thermo-mechanical behaviour of 19-element PHWR fuel bundle having AHWR fuel material

    AHWR Th-LEU of 4.3 weight % 235U enrichment is a fuel design option for its trial irradiation in Indian PHWRs. The important component of this option is the large enhancement in the average discharge burn-up from the core. A parametric study of the 19-element fuel bundle, with natural uranium currently is being used in all operating 220 MWe PHWRs, has been carried out for AHWR Th-LEU fuel material by computer code FUDA MOD2. The important fuel parameters such as fuel temperature, fission gas release, fuel swelling and sheath strain have been analyzed for required fuel performance. With Th-LEU, average discharge burnups of about 25,000 MW-d/TeHE can be achieved. The FUDA code (Fuel Design Analysis code) MOD2 version has been used in the fuel element analysis. The code takes into account the inter-dependence of different parameters like fuel pellet temperatures, pellet expansions, fuel-sheath gap heat transfer, sheath strain and stresses, fission gas release and gas pressures, fuel densification etc. Thermo-mechanical analysis of fuel element having AHWR material is carried out for the bundle power histories reaching up to design burn-up 40000 MWd/TeHE. The resultant parameters such as fuel temperature, sheath plastic strain and fission gas pressure for AHWR fuel element were compared with respective thermo-mechanical parameters for similar fuel bundle element with natural uranium as fuel material. (author)

  20. Study of the damaging mechanisms of a copper / carbon - carbon composite under thermomechanical loading

    The purpose of this work is to understand and to identify the damaging mechanisms of Carbon-Carbon composite bonded to copper under thermomechanical loading. The study of the composite allowed the development of non-linear models. These ones have been introduced in the finite elements analysis code named CASTEM2000. They have been validated according to a correlation between simulation and mechanical tests on multi-material samples. These tests have also permitted us to better understand the behaviour of the bonding between composite and copper (damaging and fracture modes for different temperatures) under shear and tensile loadings. The damaging mechanisms of the bond under thermomechanical loading have been studied and identified according to microscopic observations on mock-ups which have sustained thermal cycling tests: some cracks appear in the composite, near the bond between the composite and the copper. The correlation between numerical and experimental results have been improved because of the reliability of the composite modelization, the use of residual stresses and the results of the bond mechanical characterization. (author)

  1. Study of the damaging mechanisms of a carbon - carbon composite bonded to copper under thermomechanical loading

    The purpose of this work is to understand and to identify the damaging mechanisms of Carbon-Carbon composite bonded to copper under thermomechanical loading. The study of the composite allowed the development of non-linear models. These ones have been introduced in the finite elements analysis code named CASTEM 2000. They have been validated according to a correlation between simulation and mechanical tests on multi-material samples. These tests have also permitted us to better understand the behaviour of the bonding between composite and copper (damaging and fracture modes for different temperatures) under shear and tensile loadings. The damaging mechanisms of the bond under thermomechanical loading have been studied and identified according to microscopic observations on mock-ups which have sustained thermal cycling tests: some cracks appear in the composite, near the bond between the composite and the copper. The correlation between numerical and experimental results have been improved because of the reliability of the composite modelization, the use of residual stresses and the results of the bond mechanical characterisation. (author)

  2. Based on ABAQUS In-situ stress Balance of Geotechnical Engineering%基于ABAQUS岩土工程中地应力平衡的探讨

    马云峰

    2014-01-01

    平衡地应力是岩土工程计算分析中十分重要的部分,在岩土施工前保证地表位移近似为零,是数值模拟的首要前提。利用 ABAQUS 对某基坑开挖前的土体进行地应力平衡,根据现场土体的物理性质指标,将地应力平衡前后土体的应力和位移进行对比。进行地应力平衡后土体的位移数量级小于10-6,并且任意深度的竖向应力值等于该处深度与土体密度的乘积。%Balance in-situ stress is very important part in geotechnical engineering calculation, in front of the geotechnical construction guarantee approximation of surface displacement is zero, is the first premise of numerical simulation. Using ABAQUS to some soil excavation in front of the in-situ stress balance, according to the field of soil physical property indexes, the in-situ stress balance of stress and displacement of soil before and after comparison. In-situ stress balance of soil displacement of orders of magnitude less than 10-6, and the depth of the vertical stress value equal to the depth and the product of the density of soil.

  3. The Damage Law of HTPB Propellant under Thermomechanical Loading

    Liu, Cheng-wu; Yang, Jian-hong; Wang, Xian-meng; Ma, Yong-kang

    2016-01-01

    By way of measuring the acoustic emission (AE) signals of Hydroxyl-terminated polybutadiene (HTPB) propellant in condition of uniform speed, and combined with the scanning electron microscopy (SEM) fracture surface observation, the damage law of HTPB composite solid propellant under thermomechanical loading was studied. The results show that the effects of thermomechanical loading on HTPB propellant are related to the time and can be divided into three different stages. In the first stage, thermal air aging dominates; in the second stage, interface damage is dominant; and in the third stage, thermal air aging is once again dominant.

  4. Computer codes for the analysis of flask impact problems

    This review identifies typical features of the design of transportation flasks and considers some of the analytical tools required for the analysis of impact events. Because of the complexity of the physical problem, it is unlikely that a single code will adequately deal with all the aspects of the impact incident. Candidate codes are identified on the basis of current understanding of their strengths and limitations. It is concluded that the HONDO-II, DYNA3D AND ABAQUS codes which ar already mounted on UKAEA computers will be suitable tools for use in the analysis of experiments conducted in the proposed AEEW programme and of general flask impact problems. Initial attention should be directed at the DYNA3D and ABAQUS codes with HONDO-II being reserved for situations where the three-dimensional elements of DYNA3D may provide uneconomic simulations in planar or axisymmetric geometries. Attention is drawn to the importance of access to suitable mesh generators to create the nodal coordinate and element topology data required by these structural analysis codes. (author)

  5. Precision Glass Molding: Validation of an FE Model for Thermo-Mechanical Simulation

    Sarhadi, Ali; Hattel, Jesper Henri; Hansen, Hans Nørgaard

    2014-01-01

    glass molding process including heating, pressing, and cooling stages. Temperature- dependent viscoelastic and structural relaxation behavior of the glass material are implemented through a FORTRAN material subroutine (UMAT) into the commercial FEM program ABAQUS, and the FE model is validated...

  6. Simulation of the irradiation-induced thermo-mechanical behaviors evolution in monolithic U–Mo/Zr fuel plates under a heterogeneous irradiation condition

    Highlights: • The three-dimensional stress update algorithms in a co-rotational framework are developed for U–Mo and Zircalloy with the irradiation effects. • An effective method for three-dimensional modeling of the in-pile behaviors in heterogeneously irradiated monolithic fuel plates is established and validated. • The effects of the fission-induced creep effects in the U–Mo foil are investigated in detail. • A deformation phenomenon similar to the irradiation experimental results is obtained. - Abstract: For monolithic fuel plates with U–Mo foil and Zircalloy cladding, the three-dimensional large deformation incremental constitutive relations and stress update algorithms in the co-rotational coordinate framework are developed for the fuel and cladding with their respective irradiation effects involved. Three-dimensional finite element simulation of their in-pile thermo-mechanical coupling behaviors under a location-dependent irradiation condition is implemented via the validated user-defined subroutines UMATHT and UMAT in ABAQUS. Comparison of the simulation results for two cases with or without creep considered in the U–Mo foil indicates that with the irradiation creep included (1) considerable stress-relaxation appears in the U–Mo foil, and the mechanical interaction between fuel and cladding is weakened; (2) approximately identical thickness increments in the plate and fuel foil exist and become comparably larger; (3) plastic deformation in the cladding is significantly diminished

  7. Thermomechanical loading applied on the cladding tube during the pellet cladding mechanical interaction phase of a rapid reactivity initiated accident

    Hellouin de Menibus, Arthur, E-mail: arthur.hellouin-de-menibus@cea.fr [CEA Saclay/DEN/DANS/DMN/SRMA, 91191 Gif-sur-Yvette (France); Sercombe, Jerome [CEA Cadarache/DEN/CAD/DEC/SESC, 13108 St Paul lez Durance (France); Auzoux, Quentin; Poussard, Christophe [CEA Saclay/DEN/DANS/DMN/SEMI, 91191 Gif-sur-Yvette (France)

    2014-10-15

    Calculations of the CABRI REP-Na5 pulse were performed with the ALCYONE code in order to determine the evolution of the thermomechanical loading applied on the cladding tube during the Pellet–Cladding Mechanical Interaction (PCMI) phase of a rapid Reactivity Initiated Accident (RIA) initiated at 280 °C that lasted 8.8 ms. The evolution of the following parameters are reported: the cladding temperature, heating rate, strain rate and loading biaxiality. The impact of these parameters on the cladding mechanical behavior and fracture are then briefly reviewed.

  8. Thermo-mechanical Analysis of the CLIC Post-Linac Energy Collimators

    Resta-Lopez, J; Latina, A

    2012-01-01

    The post-linac energy collimation system of the Compact Linear Collider (CLIC) has been designed for passive protection of the Beam Delivery System (BDS) against miss-steered beams due to failure modes in the main linac. In this paper, a thermo-mechanical analysis of the CLIC energy collimators is presented. This study is based on simulations using the codes FLUKA and ANSYS when an entire bunch train hits the collimators. Different failure mode scenarios in the main linac are considered. The aim is to improve the collimator in order to make a reliable and robust design so that survives without damage the impact of a full bunch train in case of likely events generating energy errors.

  9. Thermomechanical effects on permeability for a 3-D model of YM rock

    The authors estimate how thermomechanical processes affect the spatial variability of fracture permeability for a 3-D model representing Topopah Spring tuff at the nuclear-waste repository horizon in Yucca Mountain, Nevada. Using a finite-difference code, they compute thermal stress changes. They evaluate possible permeability enhancement resulting from shear slip along various mapped fracture sets after 50 years of heating, for rock in the near-field environment of the proposed repository. The results indicate permeability enhancement of a factor of 2 for regions about 10 to 30 m above drifts, for north-south striking vertical fractures. Shear slip and permeability increases of a factor of 4 can occur in regions just above drifts, for east-west striking vertical fractures. Information on how permeability may change over the lifetime of a geologic repository is important to the prediction and evaluation of repository performance

  10. A program to validate computer codes for container impact analysis

    The detailed analysis of containers during impacts to assess either margins to failure or the consequences of different design strategies, requires the use of sophisticated computer codes to model the interactions of the various structural components. The combination of plastic deformation, impact and sliding at interfaces and dynamic loading effects provides a severe test of both the skill of the analyst and the robustness of the computer codes. A program of experiments has been under way at Winfrith since 1987 using extensively instrumented models to provide data for the validation of such codes. Three finite element codes, DYNA3D, HONDO-II and ABAQUS, were selected as suitable tools to cover the range of conditions expected in typical impacts. The impact orientation, velocity and instrumentation locations for the experiments are specified by pre-test calculations using these codes. Post-test analyses using the actual impact orientation and velocities are carried out as necessary if significant discrepancies are found

  11. Strengthening of Aluminum Alloy 2219 by Thermo-mechanical Treatment

    Li, Xifeng; Lei, Kun; Song, Peng; Liu, Xinqin; Zhang, Fei; Li, Jianfei; Chen, Jun

    2015-10-01

    Strengthening of aluminum alloy 2219 by thermo-mechanical treatment has been compared with artificial aging. Three simple deformation modes including pre-stretching, compression, and rolling have been used in thermo-mechanical treatment. The tensile strength, elongation, fracture feature, and precipitated phase have been investigated. The results show that the strengthening effect of thermo-mechanical treatment is better than the one of artificial aging. Especially, the yield strength significantly increases with a small decrease of elongation. When the specimen is pre-stretched to 8.0%, the yield strength reaches 385.0 MPa and increases by 22.2% in comparison to the one obtained in aging condition. The maximum tensile strength of 472.4 MPa is achieved with 4.0% thickness reduction by compression. The fracture morphology reveals locally ductile and brittle failure mechanism, while the coarse second-phase particles distribute on the fracture surface. The intermediate phases θ″ or θ' orthogonally precipitate in the matrix after thermo-mechanical treatment. As compared to artificial aging, the cold plastic deformation increases distribution homogeneity and the volume fraction of θ'' or θ' precipitates. These result in a better strengthening effect.

  12. Stress wave propagation in the Institute of Thermomechanics

    Okrouhlík, Miloslav

    Prague : ITAM AS CR, v. v. i., 2012 - (Náprstek, J.; Fischer, C.), s. 969-970 ISBN 978-80-86246-40-6. [Engineering Mechanics 2012 /18./. Svratka (CZ), 14.05.2012-17.05.2012] Institutional research plan: CEZ:AV0Z20760514 Keywords : historical survey * stress wave propagation in solids * Institute of Thermomechanics Subject RIV: BI - Acoustics

  13. A piezo-thermal probe for thermomechanical analysis

    Gaitas, A.; Gianchandani, S.; Zhu, W.

    2011-01-01

    Thermomechanical analysis (TMA) is widely used to characterize materials and determine transition temperatures and thermal expansion coefficients. Atomic-force microscopy (AFM) microcantilevers have been used for TMA. We have developed a micromachined probe that includes two embedded sensors: one fo

  14. THERMO-MECHANICALLY PROCESSED ROLLED WIRE FOR HIGH

    V. A. Lutsenko

    2015-06-01

    Full Text Available It is shown that at twisting of wire of diameter 1,83 mm, produced by direct wire drawing of thermomechanically processed rolled wire of diameter 5,5 mm of steel 90, metal stratification is completely eliminated at decrease of carbon, manganese and an additional alloying of chrome.

  15. Obtaining a TRIP microstructure by thermomechanical treatment without isothermal holding

    Masek, B.; Jirkova, H.; Kucerova, L.; F-X Wagner, M.

    2016-03-01

    The contemporary development of technological processes for the production of modern multiphase steels can be characterized by the need for precise control of their technological parameters. The design of modern technological processes that allow sophisticated microstructures to be obtained usually cannot be carried out on real production equipment for technical as well as economical reasons. Therefore, new processes and test devices are continuously being developed to make it possible to simulate and model thermomechanical treatments on small specimens with precise control and monitoring of process parameters. A simulator for experimental modelling of thermomechanical processes has been developed at the University of West Bohemia. In this paper, to demonstrate the feasibility of simulating thermomechanical treatments with this setup on a lab scale, we discuss the thermomechanical treatment of TRIP steels without isothermal holding - a processing route that is difficult to handle and thus poses several technological as well as economic problems. The realistic processing of wire rolling with different cooling strategies is tested on the TRIP CMnSiNb steel. Our results show that the processing route without isothermal holding allows to obtain multiphase microstructures with a tensile strength of up to 835 MPa and a ductility A5mm = 25%.

  16. On the simulation of thermo-mechanical forming processes

    Huetink, J.

    1986-01-01

    A formulation for elastic-plastic constitutive equations is given based on principles of continuum thermo-mechanics and thermodynamics. Energy dissipation and phase changes are included in the mathematical model. It is shown that kinematic hardening can be described properly for large deformations,

  17. Thermomechanical fatigue and damage mechanisms in Sanicro 25 steel

    Petráš, Roman; Škorík, Viktor; Polák, Jaroslav

    2016-01-01

    Roč. 650, JAN (2016), s. 52-62. ISSN 0921-5093 R&D Projects: GA MŠk(CZ) EE2.3.30.0063 Institutional support: RVO:68081723 Keywords : thermomechanical fatigue * Sanicro 25 steel * damage mechanism * FIB cutting * localized oxidation-cracking Subject RIV: JL - Materials Fatigue, Friction Mechanics Impact factor: 2.567, year: 2014

  18. Performance analysis of VVER-type fuel rods with the STOFFEL-1 computer code

    The main features of the fuel rod performance modelling computer code STOFFEL-1 are described. Submodels of the code are briefly characterized, and some results of comparisons between model predictions and experiments are presented. Examples of modelling calculations are given for some thermo-mechanical values of VVER-1000 fuel rods. (author)

  19. 基于ABAQUS的列车盘型制动的温度场分析%Analysis on Temperature Field of Train Disc Brake Based on ABAQUS

    王国顺

    2013-01-01

    The influences of rotating speed and the friction radius,height and shape,and place form of braking block on the temperature field of the brake disc and brake block were simulated by the finite element analysis software of ABAQUS.The results show that with the increase of crank's rotating speed,the brake disc and brake block's temperatures are increased,and the distribution of high temperature region is changed from stripe to speckle.The reason is that with the increase of revolving speed,the vibration between the friction pairs is aggravated,and the local contact was produced to cause the high temperature.There is an inflection point of temperature in the thickness direction of brake disc,with the increase of the distance to the friction surface,the temperature is declined rapidly,and in the distance of 3 ~ 6 mm to the friction surface,the change of temperature is not obvious.The change of brake block height or shape has no obvious influence on the brake disc temperature,while the placement form of the triangle brake block has influence on temperature distribution.%应用有限元软件ABAQUS,模拟转动速度和制动块摩擦半径、高度以及形状与放置形式等对制动盘和制动块温度场的影响.得出如下结论:随转速的提高,制动盘和制动块温度升高,高温区的分布由条带状向斑点状转变,原因在于随转速增加,摩擦副间的振动程度加剧,从而造成局部接触产生高温.制动盘温度在厚度方向上存在一个拐点,随深度增加,制动盘温度快速下降,在距摩擦表面3~6mm时,温度变化不明显.制动块高度、形状改变,对制动盘温度无明显影响,而三角形制动块的放置形式对制动块温度分布有影响.

  20. Thermomechanical behavior of Mexican fabricated fuel

    The Fuel Fabrication Pilot Plant of the Instituto Nacional de Investigaciones Nucleares (ININ-National Institute of Nuclear Research supplied four fuel assemblies of the GE9B type for the Laguna Verde Nuclear Power Plant (LVNPP). The Institute carried out the ceramic and fuel rod fabrication and assembled the fuel bundles, using General Electric Nuclear Energy (GENE) materials. This company licensed the Mexican Nuclear Research Institute as fuel supplier for the LVNPP, provided technical support, and issued the nuclear and mechanical fuel performance guarantees for the ININ fuel. Irradiation was carried out at Unit 1 of LVNPP and fuel burnup was calculated with the HELIOS-CM-PRESTO system. Post-irradiation examination of the Institute fuel was not performed because of the high costs involved. However, the exhaustive Q.C. carried out during fabrication permitted the use of real values for many fabrication parameters. A computational code is currently being developed for evaluating the neutronic, thermal and mechanical performance of a fuel element under several different operation conditions. This code has been benchmarked with against data from the LVNPP. (authors)

  1. A holistic approach to thermomechanical processing of alloys

    S Venugopal; Baldev Raj

    2003-06-01

    New process design and control methods are needed for significantly improving productivity and reducing costs of thermomechanical processes such as hot metal forging. Current practices for accomplishing basic design tasks such as selecting the number of forming steps and specifying the processing conditions for each thermomechanical operation produce feasible solutions that are often far from optimal. Substantial improvements in effectiveness and efficiency can be realized through holistic approaches that optimize the whole system performance and not just individual subsystems such as workpiece material behavior, material flow in dies, and equipment responses. Recent progress in the application of dynamical modelling and process design techniques using ideal forming concepts and trajectory optimization are discussed. Monitoring methods for the on-line monitoring of the process and an intelligent forging system has been proposed.

  2. Hydrogen embrittlement of thermomechanically treated 18Ni Maraging steel

    The influence of thermomechanical treatments on susceptibility to cracking in 100 percent relative humidity air and low pressure (93.3 KPa) gaseous hydrogen has been investigated for 18Ni (350 ksi) Maraging steel. Two thermomechanical treatments were studied, ausforming and marforming and compared with the standard solution treated and aged material. Although little difference exists for the strength and toughness values between these treatments, a two to five-fold increase in the stress intensity threshold for cracking was found for both the ausformed and marformed material. A dramatic difference in cracking kinetics was also apparent as shown by the failure times at comparable stress intensities. Fractographic analysis showed that the primary fracture mode was 100 percent intergranular for the solution treated and aged samples while the ausform and marform failures were predominately quasi-cleavage or intergranular depending on orientation. Finally, permeation and diffusion measurements were conducted on the above materials and these results are correlated with the environmental cracking behavior

  3. Thermomechanics analysis and optimization for high power density blanket

    Thermomechanics analysis, i.e. steady thermal analysis and steady thermal stress analysis have been carried out for a high power density blanket. The Fusion Experimental Breeder (FEB) is adopted as the reference reactor. The parts for the blanket module in Pro/ENGINEER were created, then turn to Pro/MECHANICA functionality for thermomechanics analysis. During analysis, the distribution of the power density in the blanket was optimized to be more flat, the arched curvature and rounds of the cooling tube panels were optimized to less stiffness, and the boundary condition at the interface of helium cooling tube panel and manifold chamber was optimized, which is reasonable by using advanced welding processes with electron beam or laser beam in a single pass. To the end, a maximum temperature Tm 350 degree C and a maximum shear stress τm 80 MPa for the helium cooling panels have been shown in the calculations. (authors)

  4. Thermomechanical process intensification for oil extraction from orange peels.

    Rezzoug, Sid-Ahmed; Louka, Nicolas

    2009-01-01

    The study investigated the intensification and improvement of oil extraction from orange peel through a thermomechanical process: the Instantaneous Controlled Pressure Drop (briefly D.I.C process). This process involves subjecting orange peel for a short time to steam pressure, followed by an instantaneous decompression to vacuum at 50 mbar. Central composite design was used to study the combined effects of processing steam pressure (1–7 bar; which corresponds to a temperature ranging between...

  5. Thermomechanical Behavior of High Performance Epoxy/Organoclay Nanocomposites

    Artur Soares Cavalcanti Leal; Carlos Jose de Araújo; Antônio Gilson de Barbosa Lima; Suédina Maria Lima Silva

    2014-01-01

    Nanocomposites of epoxy resin containing bentonite clay were fabricated to evaluate the thermomechanical behavior during heating. The epoxy resin system studied was prepared using bifunctional diglycidyl ether of bisphenol A (DGEBA), crosslinking agent diaminodiphenylsulfone (DDS), and diethylenetriamine (DETA). The purified bentonite organoclay (APOC) was used in all experiments. The formation of nanocomposite was confirmed by X-ray diffraction analysis. Specimens of the fabricated nanocompo...

  6. Progress in thermomechanical control of steel plates and their commercialization

    Kiyoshi Nishioka and Kazutoshi Ichikawa

    2012-01-01

    The water-cooled thermomechanical control process (TMCP) is a technology for improving the strength and toughness of water-cooled steel plates, while allowing control of the microstructure, phase transformation and rolling. This review describes metallurgical aspects of the microalloying of steel, such as niobium addition, and discusses advantages of TMCP, for example, in terms of weldability, which is reduced upon alloying. Other covered topics include the development of equipment, distortio...

  7. ISOTHERMAL AND THERMOMECHANICAL FATIGUE OF A NICKEL-BASE SUPERALLOY

    Carlos Carvalho Engler-Pinto Júnior; Dirceu Spinelli

    2014-01-01

    Thermal gradients arising during transient regimes of start-up and shutdown operations produce a complex thermal and mechanical fatigue loading which limits the life of turbine blades and other engine components operating at high temperatures. More accurate and reliable assessment under non-isothermal fatigue becomes therefore mandatory. This paper investigates the nickel base superalloy CM 247LC-DS under isothermal low cycle fatigue (LCF) and thermomechanical fatigue (TMF). Test ...

  8. Finite elements for the thermomechanical calculation of massive structures

    The paper examines the fine element analysis of thermal stress and deformation problems in massive structures. To this end compatible idealizations are utilized for heat conduction and static analysis in order to minimize the data transfer. For transient behaviour due to unsteady heat flow and/or inelastics material processes the two computational parts are interwoven in form of an integrated software package for finite element analysis of thermomechanical problems in space and time. (orig.)

  9. Thermo-mechanical design aspects of mercury bombardment ion thrusters.

    Schnelker, D. E.; Kami, S.

    1972-01-01

    The mechanical design criteria are presented as background considerations for solving problems associated with the thermomechanical design of mercury ion bombardment thrusters. Various analytical procedures are used to aid in the development of thruster subassemblies and components in the fields of heat transfer, vibration, and stress analysis. Examples of these techniques which provide computer solutions to predict and control stress levels encountered during launch and operation of thruster systems are discussed. Computer models of specific examples are presented.

  10. Thermo-mechanical properties of compressed rubber block

    Pešek, Luděk; Půst, Ladislav; Šulc, Petr

    Besancon: Comité Francais pour la Promotion de la Science des Mécanismes et des Machines, 2007 - (Merlet, J.; Dahan, M.), s. 868-873 [IFToMM 2007 /12./. Besancon (FR), 17.06.2007-21.06.2007] R&D Projects: GA ČR GA101/05/2669 Institutional research plan: CEZ:AV0Z20760514 Keywords : vibrodamping elements * thermo-mechanic interaction * rubber Subject RIV: BI - Acoustics

  11. A thermomechanical pretreatment to improve enzymatic hydrolysis of wheat straw

    Maache-Rezzoug, Zoulikha; Maugard, Thierry; Nouviaire, Armelle; Goude, Romain; Geoffroy, Stanley; Rezzoug, Sid-Ahmed

    2009-01-01

    International audience Wheat straw was pretreated with a thermomechanical process developed in our laboratory to increase the enzymatic hydrolysis extent of potentially fermentable sugars. This process involves subjecting the lignocellulosic biomass for a short time to saturated steam pressure, followed by an instantaneous decompression to vacuum at 50 mbar. Increasing of the heat induced by the saturated steam result in intensive vapour formation in the capillary porous structure of the p...

  12. Thermo-mechanical behaviour of a compacted swelling clay

    TANG, Anh Minh; Cui, Yu-Jun; Barnel, Nathalie

    2008-01-01

    International audience Compacted unsaturated swelling clay is often considered as a possible buffer material for deep nuclear waste disposal. An isotropic cell permitting simultaneous control of suction, temperature and pressure was used to study the thermo-mechanical behaviour of this clay. Tests were performed at total suctions ranging from 9 to 110 MPa, temperature from 25 to 80 °C, isotropic pressure from 0.1 to 60 MPa. It was observed that heating at constant suction and pressure indu...

  13. Fuel performance analysis code 'FAIR'

    For modelling nuclear reactor fuel rod behaviour of water cooled reactors under severe power maneuvering and high burnups, a mechanistic fuel performance analysis code FAIR has been developed. The code incorporates finite element based thermomechanical module, physically based fission gas release module and relevant models for modelling fuel related phenomena, such as, pellet cracking, densification and swelling, radial flux redistribution across the pellet due to the build up of plutonium near the pellet surface, pellet clad mechanical interaction/stress corrosion cracking (PCMI/SSC) failure of sheath etc. The code follows the established principles of fuel rod analysis programmes, such as coupling of thermal and mechanical solutions along with the fission gas release calculations, analysing different axial segments of fuel rod simultaneously, providing means for performing local analysis such as clad ridging analysis etc. The modular nature of the code offers flexibility in affecting modifications easily to the code for modelling MOX fuels and thorium based fuels. For performing analysis of fuel rods subjected to very long power histories within a reasonable amount of time, the code has been parallelised and is commissioned on the ANUPAM parallel processing system developed at Bhabha Atomic Research Centre (BARC). (author). 37 refs

  14. A finite element model for thermomechanical analysis in casting processes

    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.)

  15. Modelling of WWER fuel rod during LOCA conditions using FEM code ANSYS

    The report presents the results of the computer simulation of the IFA-650.6 experiment, the sixth test in Halden LOCA test project series, performed in May 18, 2007 with a pre-irradiated WWER-440 fuel with maximum burnup of 56 MWd/kgU. The thermo-mechanical analysis was fulfilled with the license finite element ANSYS code package.The calculation was carried out with the 2D axisymmetric and 3D problem definitions. Analysis of the calculational results shows that the ANSYS code can adequately simulate thermo-mechanical behavior of cladding under IFA-650.6 test conditions. (authors)

  16. Free Vibration Analysis for Layered Shells Accounting of Variable Kinematic and Thermo-Mechanical Coupling

    S. Brischetto; Carrera, E.

    2012-01-01

    The free vibration analysis of one-layered and two-layered metallic cylindrical shell panels is evaluated in this work. The free frequency values are investigated for both thermo-mechanical and pure mechanical problems. Thermo-mechanical frequencies are calculated by means of a fully coupled thermo-mechanical model where both the displacement and temperature are primary variables in the considered governing equations. Pure mechanical frequencies are obtained from a mechanical model where the ...

  17. Neutronic and thermo-mechanic calculations for the design of the TRADE spallation target

    The spallation target of the TRADE Project-at present in stand-by waiting for further decisions on budget availability-is based on the concept of a solid target cooled by forced convection. The solid target approach presents a maximum power density limitation due to the high thermal stresses which are generated by the huge differential temperatures in the material. These at their turn stem from the proton energy loss in the volume of the target material and the water cooling on the external surface. The maximum operating beam power and the proton beam profile were imposed by experimental and geometrical considerations; the peak power density of the target material (Tantalum) turned out to be about 8E09 W/m3. The power generation of the reference configuration of the spallation target was accurately calculated by the code MCNPX, which allows to simulate individual particle tracks in 3-D geometry, starting from the accelerated 140 MeV protons down to all the relevant secondary particles. The temperature distribution and the stress and strain maps were calculated by the thermo-mechanical ANSYS code. The main calculation results are reported. The elastic-plastic analysis of the target material is performed in terms of maximum allowable deformation, fatigue and progressive plastic deformation

  18. Transient Thermo-Mechanical Analysis of the TPSG4 Beam Diluter

    Goddard, B; Herrera-Martínez, A; Kadi, Y; Marque, S

    2002-01-01

    A new extraction channel is being built in the Super Proton Synchrotron (SPS) Long Straight Section 4 (LSS4) to transfer proton beams to the Large Hadron Collider (LHC) and also to the CERN Neutrino to Gran Sasso (CNGS) target. The beam is extracted in a fast mode during a single turn. For this purpose a protection of the MSE copper septum coil, in the form of a beam diluting element placed upstream, will be required to cope with the new failure modes associated with the fast extraction operation. The present analysis focuses on the thermo-mechanical behavior of the proposed TPSG4 diluter element irradiated by a fast extracted beam (up to 4.9 x 10^13 protons per 7.2 mus pulse) from the SPS. The deposited energy densities, estimated from primary and secondary particle simulations using the high-energy particle transport code FLUKA, were converted to internal heat generation rates taken as a thermal load input for the finite-element engineering analyses code ANSYS. According to the time dependence of the extrac...

  19. DART-TM: A thermomechanical version of DART for LEU VHD dispersed and monolithic fuel analysis

    A collaboration agreement between ANL/USDOE and CNEA Argentina, in the area of Low Enriched Uranium Advanced Fuels has been in place since October 16, 1997 under the 'Implementation Arrangement for Technical Exchange and Cooperation in the Area of Peaceful Uses of Nuclear Energy'. An annex concerning DART code optimization has been operative since February 8, 1999. Previously, as a part of this annex a visual thermal FASTDART version was developed that includes mechanistic models for the calculation of the fission-gas-bubble and fuel particle size distribution, reaction layer thickness, and meat thermal conductivity. FASTDART was presented at the last RERTR Meeting that included validation against RERTR 3 irradiation data. The thermal FASTDART version was assessed as an adequate tool for modeling the behavior of LEU U-Mo dispersed fuels under irradiation against PIE RERTR irradiation data. During this past year the development of a 3-D thermo-mechanical version of the code for modeling the irradiation behavior of LEU U-Mo monolithic and dispersion fuel was initiated. Some preliminary results of this work will be shown during RERTR-2003 meeting. (author)

  20. Clinical coding. Code breakers.

    Mathieson, Steve

    2005-02-24

    --The advent of payment by results has seen the role of the clinical coder pushed to the fore in England. --Examinations for a clinical coding qualification began in 1999. In 2004, approximately 200 people took the qualification. --Trusts are attracting people to the role by offering training from scratch or through modern apprenticeships. PMID:15768716

  1. Permutation codes

    Ericson, Thomas

    1993-01-01

    Slepians permutation codes are investigated in detail. In particular we optimize the initial vector and derive all dominating codes in dimension n 2 6. With the exception of the simplex and biorthogonal codes - which are always included as special cases of permutation codes - there are probably no further good codes in higher dimensions.

  2. Thermo-mechanical behavior of epoxy shape memory polymer foams

    Di Prima, M. A.; Lesniewski, M.; Gall, K.; McDowell, D. L.; Sanderson, T.; Campbell, D.

    2007-12-01

    Shape memory polymer foams have significant potential in biomedical and aerospace applications, but their thermo-mechanical behavior under relevant deformation conditions is not well understood. In this paper we examine the thermo-mechanical behavior of epoxy shape memory polymer foams with an average relative density of nearly 20%. These foams are deformed under conditions of varying stress, strain, and temperature. The glass transition temperature of the foam was measured to be approximately 90 °C and compression and tensile tests were performed at temperatures ranging from 25 to 125 °C. Various shape recovery tests were used to measure recovery properties under different thermo-mechanical conditions. Tensile strain to failure was measured as a function of temperature to probe the maximum recovery limits of the foam in both temperature and strain space. Compression tests were performed to examine compressibility of the material as a function of temperature; these foams can be compacted as much as 80% and still experience full strain recovery over multiple cycles. Furthermore, both tensile strain to failure tests and cyclic compression recovery tests revealed that deforming at a temperature of 80 °C maximizes macroscopic strain recovery. Deformation temperatures above or below this optimal value lead to lower failure strains in tension and the accumulation of non-recoverable strains in cyclic compression. Micro-computed tomography (micro-CT) scans of the foam at various compressed states were used to understand foam deformation mechanisms. The micro-CT studies revealed the bending, buckling, and collapse of cells with increasing compression, consistent with results from published numerical simulations.

  3. Proceedings of the first thermomechanical workshop for shale

    Chapter 2 provides a description of the three federal regulations that pertain to the development of a high-level nuclear waste repository regardless of the rock type. Chapter 3 summarizes the reference shale repository conditions selected for this workshop. A room-and-pillar configuration was considered at an extraction ratio of about 0.25. The depth was assumed to be 700 m. Chapter 4 gives a summary of several case histories that were considered to be valuable in gaining an understanding of some of the design and construction features that might be unique in creating underground openings in shale. Chapter 5 assesses the data and information needs, availability, technology for acquisition, and the research and development necessary for analytical/numerical modeling in heat transfer, fluid flow, and thermomechanics. Chapter 6 assesses data and information needs in the laboratory and considerations associated with shale rock characterization. Chapter 7 assesses the data and information needs, availability, technology for acquisition, and the research and development necessary for field/in situ testing. Chapter 8 presents the consensus of the workshop participants that there is a definite need to advance the state of knowledge concerning the thermomechanical behavior of shales and to gain experience in applying this knowledge to the design of room-and-pillar excavations. Finally, Chapter 9 provides a summary of the research and development needs in the various interacting activities of repository development, including analytical/numerical modeling, laboratory testing, and field/in situ testing. The main conclusion of the workshop was that a need exists for an aggressive program in laboratory, field, numerical modeling, and design studies to provide a thermomechanical, technological base for comparison of shale types and shale regions/areas/sites

  4. On thermo-mechanical issues induced by irradiation swelling inside the back-plate of the IFMIF target assembly

    Within the framework of the IFMIF R and D program and in close cooperation with ENEA-Brasimone, at the Department of Nuclear Engineering of the University of Palermo a research campaign has been launched to investigate the thermo-mechanical issues potentially induced by irradiation swelling in the threaded connections between frame and back-plate of IFMIF target assembly. The main aim of the research campaign has relied in the assessment of the maximum swelling-induced volumetric strain that may be accepted in order to allow screws to withstand thermo-mechanical stresses and work in safe conditions or to avoid unduly high unscrewing torques during back-plate remotely handled maintenance operations. A theoretical approach based on the Finite Element Method (FEM) has been followed and a quoted commercial code has been adopted to perform the study. Since swelling-induced volumetric strain distribution within back-plate has not yet been assessed, a parametric analysis has been carried out, assuming swelling-induced volumetric strains ranging from 0.001% to 0.1%. A realistic 3D FEM model of a portion of frame and back-plate pertaining to a single screw has been set-up and a realistic set of loads and boundary conditions has been imposed. The results obtained are presented and critically discussed.

  5. The Numerical Nuclear Reactor for High-Fidelity Integrated Simulation of Neutronic, Thermal-Hydraulic, and Thermo-Mechanical Phenomena

    A comprehensive high fidelity reactor core modeling capability has been developed for detailed analysis of current and advanced reactor designs as part of a US-ROK collaborative I-NERI project. High fidelity was accomplished by integrating highly refined solution modules for the coupled neutronic, thermal-hydraulic, and thermo-mechanical phenomena. Each solution module employs methods and models that are formulated faithfully to the first-principles governing the physics, real geometry, and constituents. Specifically, the critical analysis elements that are incorporated in the coupled code capability are whole-core neutron transport solution, ultra-fine-mesh computational fluid dynamics/heat transfer solution, and finite-element-based thermo-mechanics solution, all obtained with explicit (fuel pin cell level) heterogeneous representations of the components of the core. The vast computational problem resulting from such highly refined modeling is solved on massively parallel computers, and serves as the 'numerical nuclear reactor'. Relaxation of modeling parameters were also pursued to make problems run on clusters of workstations and PCs for smaller scale applications as well

  6. The Numerical Nuclear Reactor for High-Fidelity Integrated Simulation of Neutronic, Thermal-Hydraulic, and Thermo-Mechanical Phenomena

    Kim, K. S.; Ju, H. G.; Jeon, T. H. and others

    2005-03-15

    A comprehensive high fidelity reactor core modeling capability has been developed for detailed analysis of current and advanced reactor designs as part of a US-ROK collaborative I-NERI project. High fidelity was accomplished by integrating highly refined solution modules for the coupled neutronic, thermal-hydraulic, and thermo-mechanical phenomena. Each solution module employs methods and models that are formulated faithfully to the first-principles governing the physics, real geometry, and constituents. Specifically, the critical analysis elements that are incorporated in the coupled code capability are whole-core neutron transport solution, ultra-fine-mesh computational fluid dynamics/heat transfer solution, and finite-element-based thermo-mechanics solution, all obtained with explicit (fuel pin cell level) heterogeneous representations of the components of the core. The vast computational problem resulting from such highly refined modeling is solved on massively parallel computers, and serves as the 'numerical nuclear reactor'. Relaxation of modeling parameters were also pursued to make problems run on clusters of workstations and PCs for smaller scale applications as well.

  7. Thermomechanical layout of the NET first wall assembly

    The 2D-finite element (FE) method is applied for the NET first wall structure to compute the quasi-harmonic steady-state temperature distribution within the wall and to determine the nonlinear elastic stresses under thermomechanical loads. 26 different cases (as proposed) have been investigated for the structure containing plane wall, grooved wall and thin wall concepts, respectively. The wall's support condition and the nonlinear material and thermal parameters are varied. The computations are carried out once with water coolant and then with high pressure helium coolant. The results are documented in this final report. (orig./GG)

  8. Thermomechanical Analysis (TMA) and its application to polymer systems

    Adams, Jillian Cathleen [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

    2016-05-25

    Thermomechanical analysis (TMA) instruments are used to measure dimensional changes as a sample is heated or cooled. Data obtained from these instruments can be used to calculate the glass transition (Tg) and the coefficient of thermal expansion (CTE). Commonly, materials expand when heated and contract when cooled; however, the rate of such changes depends largely on the type of material. In manufacturing, it is important to use components with similar CTE values to avoid product failure, leaks, or a build-up of thermal stress. Therefore, TMA is a straightforward, useful tool in research and industry.

  9. Technical Aspects of New Concentrating Solar Thermomechanic Conversion

    Ivan Herec

    2005-01-01

    Full Text Available The article concerns technical aspects of new concentrating solar thermo-mechanic conversion from the point of view of automated control algorithms of solar thermal motor working on a principle of modified Clausius-Rankin's thermal circulation. On the basis of the proposed algorithms for controlling of thermodynamic processes of the functional model of the solar thermal motor, which uses internal-system absorption of incoming heat radiation, double-step steam generation and regeneration of out coming heat, the design and the testing of controlling single-chip microprocessor electronics with specially designed software was executed.

  10. Thermo-mechanical interaction in nonlinear vibrating systems

    Pešek, Luděk; Půst, Ladislav

    Praha : Ústav termomechaniky AV ČR, 2003 - (Dobiáš, I.), s. 147-154 ISBN 80-85918-81-1. [Národní konference s mezinárodní účastí : Dynamika strojů. Praha (CZ), 11.02.2003-12.02.2003] R&D Projects: GA ČR GA101/02/0241 Institutional research plan: CEZ:AV0Z2076919 Keywords : thermo-mechanic interaction * non-linear * response curves Subject RIV: BI - Acoustics

  11. Thermomechanical CSM analysis of a superheater tube in transient state

    Taler, Dawid; Madejski, Paweł

    2011-12-01

    The paper presents a thermomechanical computational solid mechanics analysis (CSM) of a pipe "double omega", used in the steam superheaters in circulating fluidized bed (CFB) boilers. The complex cross-section shape of the "double omega" tubes requires more precise analysis in order to prevent from failure as a result of the excessive temperature and thermal stresses. The results have been obtained using the finite volume method for transient state of superheater. The calculation was carried out for the section of pipe made of low-alloy steel.

  12. Thermomechanical behavior of rapidly solidified Fe-25Cr-20Ni

    Draissia, M.; Boukhris, N.; Debili, M.Y. [LM2S, Dept. de Physique, Faculte des Sciences, Univ. Badji-Mokhtar, Annaba, Algerie (Turkey)

    2004-07-01

    The thermomechanical treatment at 1050 C under a stress of about 30 MPa, of milled ribbons from Fe-25Cr-20Ni (0.060%Ni-0.1%Ti) refractory stainless steel, leads to a recrystallisation of the as-melt-spun structure which is intermediate between cellular and columnar dendritic. The mean grain size in the relatively high density zones (85%) may be considered as low and do not exceed 10{mu}m. Other grains appear abnormally large and reach 30 {mu}m. The origin of these grains, must be researched in an exaggerate growth phenomenon under a local deformation near the critical work hardening. (orig.)

  13. Thermomechanical Behavior of High Performance Epoxy/Organoclay Nanocomposites

    Artur Soares Cavalcanti Leal

    2014-01-01

    Full Text Available Nanocomposites of epoxy resin containing bentonite clay were fabricated to evaluate the thermomechanical behavior during heating. The epoxy resin system studied was prepared using bifunctional diglycidyl ether of bisphenol A (DGEBA, crosslinking agent diaminodiphenylsulfone (DDS, and diethylenetriamine (DETA. The purified bentonite organoclay (APOC was used in all experiments. The formation of nanocomposite was confirmed by X-ray diffraction analysis. Specimens of the fabricated nanocomposites were characterized by dynamic mechanical analysis (DMA. According to the DMA results a significant increase in glass transition temperature and storage modulus was evidenced when 1 phr of clay is added to epoxy resin.

  14. Thermomechanical and macropermeability experiments in the Stripa granite: status report

    The first portion of this paper reviews the status of thermomechanical experiments just completed in the time scale and full scale drifts. The second part discusses the macropermeability experiment underway in the ventilation drift. The initial results of the macropermeability experiment show that the ventilation and pressure measurement techniques applied at Stripa can be reliably employed to generate reproduceable results in the measurement of low hydraulic conductivities in large volumes of fractured rock. LBL's tests have shown, however, that the accuracy of these techniques is quite sensitive to local geological and hydrologic conditions, and this use should be carefully evaluated for each application

  15. Thermomechanical effects caused by heavy ions propagating in tissue

    The thermomechanical effects caused by ions propagating in tissue are discussed. Large energy densities in small regions surrounding ion paths cause shock waves propagating in tissue. The strength of the shock waves depends on the linear energy transfer. Molecular dynamics simulations help in determining the necessary strength of shock waves in order for the stresses caused by them to directly produce DNA strand breaks. At much smaller values of linear energy transfer, the shock waves may be instrumental in propagating reactive species formed close to the ion's path to large distances, successfully competing with diffusion. (authors)

  16. Grain size refinement of inconel 718 thermomechanical processing

    Inconel 718 is a Ni-Fe precipitation treated superalloy. It presents good thermal fatigue properties when the material has small grain size. The aim of this work is to study the grain size refinement by thermomechanical processing, through observations of the microstructural evolution and the influence of some of the process variables in the final grain size. The results have shown that this refinement occured by static recrystallization. The presence of precipitates have influenced the final grain size if the deformations are below 60%. For greater deformations the grain size is independent of the precipitate distribution in the matrix and tends to a limit size of 5 μm. (author)

  17. Preliminary AD-Horn Thermomechanical and Electrodynamic Simulations

    Lopez Sola, Edmundo; Calviani, Marco

    2016-01-01

    As part of the Antiproton Decelerator (AD) target area consolidation activities planned for LS2, it has been necessary to perform a comprehensive study of the thermo-structural behaviour of the AD magnetic horn during operation, in order to detail specific requirements for the upgrade projects and testing procedures. The present work illustrates the preliminary results of the finite element analysis carried out to evaluate the thermal and structural behaviour of the device, as well as the methodology used to model and solve the thermomechanical and electrodynamic simulations performed in the AD magnetic horn.

  18. A radiation change in the properties of graphite after its thermomechanical treatment

    For graphite obtained by the thermomechanical treatment method the dependence of changing sample form on neutron irradiation dose and temperature. It has been found that with formation growth during thermomechanical treatment anisotropy of properties including that of form change is inccreased. It is shown that radiation changes in modulus, electric resistance, thermal expansion coefficient are anisotropic

  19. Development and validation of a fuel performance analysis code

    CAD has been developing a computer code 'FRAVIZ' for calculation of steady-state thermomechanical behaviour of nuclear reactor fuel rods. It contains four major modules viz., Thermal module, Fission Gas Release module, Material Properties module and Mechanical module. All these four modules are coupled to each other and feedback from each module is fed back to others to get a self-consistent evolution in time. The computer code has been checked against two FUMEX benchmarks. Modelling fuel performance in Advance Heavy Water Reactor would require additional inputs related to the fuel and some modification in the code.(author)

  20. Application of a new thermo-mechanical model for the study of the nuclear waste disposal in clay rocks

    Document available in extended abstract form only. One of the cornerstones of the nuclear waste disposal researches concerns the evolution of the damaged zone which can offer a preferential path for migration of radionuclide through modifications of its mechanical and hydraulic properties. Even if the thermo-mechanical behaviour of clays is well documented in the literature, the development of the damaged zone induced by an excavation with temperature is not well known. To investigate this problem, a new thermo-mechanical constitutive law has been implemented in the non-linear finite element code LAGAMINE developed at ULg (Universite de Liege) and has been used to model the PRACLAY experiment (Preliminary demonstration test for clay disposal of vitrified high level radioactive waste) at Mol URL (Underground Research Laboratory). Though several models are being to reproduce the different phenomena met when a thermal loading is applied to a clay specimen, the applications of such thermo-mechanical models to simulate large scale in-situ experiment are rare. Based on the work of Sultan a new thermo-mechanical constitutive law has been implemented in combination with a Cap model in the code LAGAMINE. The Cap model is a combination of a frictional criterion, a Cam-Clay model and a traction criterion. The influence of the temperature is considered through the thermo-mechanical law developed by Cui et al. (2000). This law permits to reproduce common features of the thermo-mechanical behaviour of clay, such as the decrease of the pre-consolidation pressure with temperature, the volume change, the thermal hardening, the transition between thermal dilation and thermal contraction for over-consolidated clays. These aspects are modelled with two curves in the (p',T) plane. The first one is related to the generation of the thermal volumetric plastic strains (TY curve (Thermal Yield)). The second one reproduces the decrease of the pre-consolidation pressure with the temperature

  1. Operating experience with the Harwell thermo-mechanical generators

    The Stirling-cycle thermo-mechanical generator (TMG) provides small amounts of electrical power continuously over long periods, while requiring much less fuel than other power sources running from hydrocarbon fuel or radio-isotopes. Two of these 25-watt generators, fuelled by propane, have been used to power the UK National Buoy on two successive missions. A total of more than three years experience at sea has now been accumulated. In addition, a 60-watt version has provided the power for a major lighthouse for more than a year. An early development version of the Thermo-mechanical Generator, adapted to run from the heat of a radio-isotope source, was loaded with strontium 90 titanate in October 1974 and has run continuously in the laboratory ever since. The improvements and changes found necessary in the course of 90,000 generator-hours of running time are described, and the improvements in operational performance and reliability which have resulted are outlined. (author)

  2. Thermomechanical design considerations of particulate reinforced silicon carbide materials

    Much attention has been paid to silicon carbides with continuous fiber reinforcement for a large-sized core component in a fusion reactor. The choice of the toughening measures may be justified by achieving a highest fracture resistance. Many efforts in the line of a continuous SiC fiber reinforcement have been made on manufacturing optimization and materials characterization including their irradiation effects at high temperatures. According to the recent investigations on neutron irradiation effects in some experimental grade SiC/SiC composites prepared by the CVI and PIP routes, it has been emphasized that properties of continuous fiber reinforced SiC composites are controlled by fiber grade, volume fraction, weave, fiber/matrix interface and matrix properties. In parallel with these efforts for plasma facing materials and components, SiC ceramic-based composites are promising for use in a high temperature reactor (HTGR) system. In order particularly to understand their envisaged complicated behaviors under high temperature neutron irradiations, one should notice those intrinsic composite parameters that are required in a micro/mesoscopic structure-based thermomechanics approach. With this direction in mind, the paper deals with essential thermomechanical phenomena in porous polycrystalline ceramics, option on particulate reinforced SiC composites, and preparation for materials testing using the HTTR. (author)

  3. Experimental identification of cohesive zone models from thermomechanical imaging techniques

    This work deals with the identification of cohesive zone models. These models were initially proposed in the 1960's. They are now more and more frequently used in numerical simulations to account for crack initiation and propagation in different materials and structures. The identification of these models still remains a delicate issue. The recent developments in imaging techniques now allow reaching local measurement fields (e.g. strain, temperature,..). We propose here to use the large amount of information given by these techniques to set up an identification procedure accounting for either the localization development (structural effect) and also the character of the different irreversibility sources encountered (thermomechanical behavior). We study damageable elasto-plastic ductile materials. Damage is associated to a cohesive behavior of the interface between volumic elements supposed to remain purely elasto-plastic. The identification procedure involves two steps. The first one consists in characterizing the shape and the parameters of the cohesive zone on tensile tests by analyzing the mechanical fields locally developed. The second one consists in checking the thermo-mechanical consistency of the identified model by confronting the calorimetric measurements deduced from temperature fields with the previsions of the identified model. This method is applied on different materials (Dual Phase steel and copper). A specific caution is conferred to the characterization of the characteristic length necessarily introduced by the identification. It is shown that this length can be estimated regarding the different parameters introduced in the image processing. (author)

  4. ISOTHERMAL AND THERMOMECHANICAL FATIGUE OF A NICKEL-BASE SUPERALLOY

    Carlos Carvalho Engler-Pinto Júnior

    2014-06-01

    Full Text Available Thermal gradients arising during transient regimes of start-up and shutdown operations produce a complex thermal and mechanical fatigue loading which limits the life of turbine blades and other engine components operating at high temperatures. More accurate and reliable assessment under non-isothermal fatigue becomes therefore mandatory. This paper investigates the nickel base superalloy CM 247LC-DS under isothermal low cycle fatigue (LCF and thermomechanical fatigue (TMF. Test temperatures range from 600°C to 1,000°C. The behavior of the alloy is strongly affected by the temperature variation, especially in the 800°C-1,000°C range. The Ramberg-Osgood equation fits very well the observed isothermal behavior for the whole temperature range. The simplified non-isothermal stress-strain model based on linear plasticity proposed to represent the thermo-mechanical fatigue behavior was able to reproduce the observed behavior for both in-phase and out-of-phase TMF cycling.

  5. Effects Of Thermo-Mechanical Treatment On ALMG2 Alloy

    Thermo-mechanical treatment consisting of hot rolling and annealing process has been applied to ALMG2 plate. The ALMG2 plate was a dressed by hot rolling process at 400o with step deformation, and the ALMG2 plate was then annealed at 425o for one-hour. The observation on the microstructure was performed by using optical metallography, the hardness test was performed using Vickers method, and thermal conductivity was measured using conductometer. Thermo-mechanical treatment generates changes in ALMG2 microstructures and mechanical properties. The changes have been identified using optical metallography and Vickers micro hardness test. The treatment transforms the ALMG-equiaxial grain to elongated grain and the alloy hardness is still relatively soft. The hardness reaches about 58,5 Kg/mm2 after deformation of 18 %, 41 % and 76 % and 66 Kg/mm2 after deformation of 133 %. An one-our annealing treatment at 425o caused decreasing of the hardness to about (41-42) Kg/mm2 for 18 %, 41 % and 76 % deformation and to about 39 Kg/mm2 for 133 % deformation. This treatment makes the form of the grain equiaxial and the site of the grain larger. The results of the measurements using conductometer on the original ALMG2 alloy and it was addressed by hot rolling indicate that thermal conductivity of 143 W/mo to 140 W/mo

  6. Surface finishing and levelling of thermomechanically hardened rolled steel

    The finishing of high-strength merchant shapes from alloy steel was tried out under industrial conditions with the equipment of metallurgical plants. After thermomechanical hardening in the production line of the rolling mill, 30KhGSN2A and 40Kh1NVA steel rounds 32 and 31 mm in diameter were straightened on a two-roller straightening machine designed by the All-Union Scientific Research Institute for Metallurgical Machinery (VNII Metmash). This made possible subsequent turning and grinding of the rods. The conditions of straightening, turning and grinding have been worked so as to obtain thermomechanically strengthened and ground rolled products approximating the gauged and ground metal in shape geometry and surface finish. It is shown that the labour-consuming operation of turning can be eliminated by reducing the machining pass of the rolled product, and this lowers the labour required for the finishing operations by 75%. After grinding with 40- and 25-grain abrasive wheels, high strength rolled shapes were obtained with a diameter of 30-0.20 mm and a surface finish of class 6-5 satisfying the technical specifications. (author)

  7. Lessons learned from the computational simulation of thermomechanical behaviour of the WWER-1000 reactor cores: FA development and its implantation into the Balakovo NPP unit 1

    The fuel assembly is forced under operation conditions by weight and hydraulic force; hold-down force; contact transversal forces; non-uniform thermal and neutron fields; thermomechanical forces in the fuel assembly multirod structure. The fuel assembly bowing has been investigated in this work. The objective of the study is to recommend the optimal design for fuel assemblies. Calculations are made using the code TEREMOK. A new generation fuel assemblies for WWER-1000 named FA-2 are suggested. The performance of the FA- 2 has been studied. The theoretical approach and the calculation technique have been verified

  8. First calculations of the thermomechanical effects following ultimate disposal of high-level radioactive wastes in a salt formation

    The thermal load of a saltdome after ultimate disposal of radioactive wastes leads to a direct heat effect, the temperature distribution, as well as a indirect heat effect, the stress/strain distribution. In the past essentially the temperature distribution had been calculated. In the mean time the thermomechanical effects of the heat dissipation will become more and more important. Therefore, the material behaviour of rock salt will be discussed and a simple mathematical description based on a rheological model will be shown. Furthermore, first results of a near field and a fare field problem in simple geometry show that the stress distribution in some parts of the calculated region is very similar to the temperature distribution. To get reliable results much researches on the material model as well as on computer codes will have to be done. (Auth.)

  9. Review of SKB's Code Documentation and Testing

    SKB is in the process of developing the SR-Can safety assessment for a KBS 3 repository. The assessment will be based on quantitative analyses using a range of computational codes aimed at developing an understanding of how the repository system will evolve. Clear and comprehensive code documentation and testing will engender confidence in the results of the safety assessment calculations. This report presents the results of a review undertaken on behalf of SKI aimed at providing an understanding of how codes used in the SR 97 safety assessment and those planned for use in the SR-Can safety assessment have been documented and tested. Having identified the codes us ed by SKB, several codes were selected for review. Consideration was given to codes used directly in SKB's safety assessment calculations as well as to some of the less visible codes that are important in quantifying the different repository barrier safety functions. SKB's documentation and testing of the following codes were reviewed: COMP23 - a near-field radionuclide transport model developed by SKB for use in safety assessment calculations. FARF31 - a far-field radionuclide transport model developed by SKB for use in safety assessment calculations. PROPER - SKB's harness for executing probabilistic radionuclide transport calculations using COMP23 and FARF31. The integrated analytical radionuclide transport model that SKB has developed to run in parallel with COMP23 and FARF31. CONNECTFLOW - a discrete fracture network model/continuum model developed by Serco Assurance (based on the coupling of NAMMU and NAPSAC), which SKB is using to combine hydrogeological modelling on the site and regional scales in place of the HYDRASTAR code. DarcyTools - a discrete fracture network model coupled to a continuum model, recently developed by SKB for hydrogeological modelling, also in place of HYDRASTAR. ABAQUS - a finite element material model developed by ABAQUS, Inc, which is used by SKB to model repository buffer

  10. ABAQUS中三维梁单元材料单轴本构模型的二次开发%Material uniaxial constitutive model secondary development of three-dimensional beam elements in ABAQUS

    袁伟泽; 陈清军

    2013-01-01

    To achieve the elastoplastic calculation of three - dimensional reinforced concrete fiber beam element in ABAQUS software, using the user - defined subroutine interface UMAT of the software implicit modules, based on the concrete constitutive theory, which combined by Mander pressure skeleton curve, Guo Zhenhai pressure loading and unloading rules and Teng Zhiming tension loading and unloading rules, and Stee102 constitutive theory of OpeenSEES, uniaxial constitutive hysteretic models for concrete and steel rebar were developed for three - dimensional fiber beam elements in ABAQUS software, then comparisons with the existing low cyclic loading test results were carried out. The results show that the user - defined material subroutines in ABAQUS software do well in simulating hysteretic behavior of the three - dimensional reinforced concrete skeletal structures.%为了在ABAQUS软件中实现对三维钢筋混凝土纤维梁单元的弹塑性计算,利用ABAQUS软件隐式模块下的用户自定义子程序接口UMAT,基于Mander受压骨架曲线、过镇海受压加卸载规则及滕智明受拉加卸载规则组合的混凝土本构理论和OpenSEES中Steel02采用的钢筋本构理论,在ABAQUS软件中开发了用于空间梁单元的混凝土和钢筋单轴本构滞回模型,并与已有的低周反复加载试验结果进行了比较.结果表明,本文基于ABAQUS软件二次开发的材料单轴滞回模型能够较好地模拟空间钢筋混凝土杆系结构的弹塑性滞回行为.

  11. Speech coding

    Gersho, Allen

    1990-05-01

    Recent advances in algorithms and techniques for speech coding now permit high quality voice reproduction at remarkably low bit rates. The advent of powerful single-ship signal processors has made it cost effective to implement these new and sophisticated speech coding algorithms for many important applications in voice communication and storage. Some of the main ideas underlying the algorithms of major interest today are reviewed. The concept of removing redundancy by linear prediction is reviewed, first in the context of predictive quantization or DPCM. Then linear predictive coding, adaptive predictive coding, and vector quantization are discussed. The concepts of excitation coding via analysis-by-synthesis, vector sum excitation codebooks, and adaptive postfiltering are explained. The main idea of vector excitation coding (VXC) or code excited linear prediction (CELP) are presented. Finally low-delay VXC coding and phonetic segmentation for VXC are described.

  12. code {poems}

    Ishac Bertran

    2012-08-01

    Full Text Available "Exploring the potential of code to communicate at the level of poetry," the code­ {poems} project solicited submissions from code­writers in response to the notion of a poem, written in a software language which is semantically valid. These selections reveal the inner workings, constitutive elements, and styles of both a particular software and its authors.

  13. Numerical simulation of thermo-mechanical fatigue properties for particulate reinforced composites

    Ran Guo; Huiji Shi; Zhenhan Yao

    2005-01-01

    In this paper, a two dimensional Voronoi cell element, formulated with creep, thermal and plastic strain, is applied for the numerical simulation of thermo-mechanical fatigue behavior for particulate reinforced composites.The relation between mechanical fatigue phases and thermal fatigue phases influences the thermo-mechanical fatigue behavior and cyclic creep damage. The topological features of micro-structure in particulate reinforced composites, such as the orientation, depth-width ratio, distribution and volume fraction of inclusions, have a great influence on thermomechanical behavior. Some related conclusions are obtained by examples of numerical simulation.

  14. Low cycle fatigue improvement of powder metallurgy titanium alloy through thermomechanical treatment

    LIU Bin; LIU Yong; HE Xiao-yu; TANG Hui-ping; CHEN Li-fang

    2008-01-01

    A low-cost β type Ti-1.5Fe-6.8Mo-4.8Al-1.2Nd (mass fraction, %)(T12LCC) alloy was produced by blended elemental powder metallurgy(P/M) method and subsequent thermomechanical treatment. Low cycle fatigue(LCF) behavior of P/M T12LCC alloy before and after thermomechanical treatment was studied. The results show that the LCF resistance of P/M titanium alloy is significantly enhanced through the thermomechanical treatment. The mechanisms for the improvement of LCF behavior are attributed to the elimination of residual pores, the microstructure refining and homogenization.

  15. A thermomechanical crystal plasticity constitutive model for ultrasonic consolidation

    Siddiq, Amir

    2012-01-01

    We present a micromechanics-based thermomechanical constitutive model to simulate the ultrasonic consolidation process. Model parameters are calibrated using an inverse modeling approach. A comparison of the simulated response and experimental results for uniaxial tests validate and verify the appropriateness of the proposed model. Moreover, simulation results of polycrystalline aluminum using the identified crystal plasticity based material parameters are compared qualitatively with the electron back scattering diffraction (EBSD) results reported in the literature. The validated constitutive model is then used to simulate the ultrasonic consolidation process at sub-micron scale where an effort is exerted to quantify the underlying micromechanisms involved during the ultrasonic consolidation process. © 2011 Elsevier B.V. All rights reserved.

  16. Thermomechanical analysis and microstructural characterization of high performance concretes

    Ren, Fei [ORNL; Wang, Jy-An John [ORNL; Dipaolo, Beverly P [ORNL

    2012-01-01

    Ultra-high performance concrete (UHPC) is a family of emerging materials for buildings and constructions. Behaviors of UHPCs at high temperatures are very important to their reliability and safety. In the current study, two UHPC materials were studied using the thermomechanical analysis (TMA) technique between room temperature and 800oC. Both reversible and irreversible phase transformations were observed from the TMA results, which were likely due to the - quartz transformation, and the decarburization and the dehydroxylation transitions, respectively. Thermal expansion coefficients exhibited significant variations in different temperature regimes. Postmortem SEM examinations revealed extensive cracking in the heated samples. In addition, micro-porosities were observed in the C-S-H phase as a result of phase changes during heating.

  17. Thermo-mechanical process for treatment of welds

    Benefits from thermo-mechanical processing (TMP) of austenitic stainless steel weldments, analogous to hot isostatic pressing (HIP) of castings, most likely result from compressive plastic deformation, enhanced diffusion, and/or increased dislocation density. TMP improves ultrasonic inspectability of austenitic stainless steel welds owing to: conversion of cast dendrites into equiaxed austenitic grains, reduction in size and number of stringers and inclusions, and reduction of delta ferrite content. TMP induces structural homogenization and healing of void-type defects and thus contributes to an increase in elongation, impact strength, and fracture toughness as well as a significant reduction in data scatter for these properties. An optimum temperature for TMP or HIP of welds is one which causes negligible grain growth and an acceptable reduction in yield strength, and permits healing of porosity

  18. Geometrical Field Formulation of Thermomechanics in Rational Mechanics

    Jianhua, Xiao

    2010-01-01

    In modern science, the thermo mechanics motion can be traced back to quantum motion in micro viewpoint. On the other hand, the thermo mechanics is definitely related with geometrical configuration motion (phase) in macro viewpoint. On this sense, the thermomechanics should be formulated by two kinds of motion: quantum motion and configuration motion. Its principle goal ought to be bridge the gap between atomic physics and engineering practice. In this research, the configuration motion is formulated by deformation geometrical field (motion transformation tensor). The quantum motion is formulated by the wave function of quantum state. Based on these two fields, the thermo stress is formulated as the coupling of quantum motion and configuration motion. Along this line, the entropy is interpreted and formulated according to thermodynamics rules. For scalar entropy, the traditional meaning of entropy is reserved. For infinitesimal configuration variation, the formulation is degenerated to the traditional elastici...

  19. Microstructure and mechanical properties of vanadium alloys after thermomechanical treatments

    The results of investigation of dispersion strengthening effect on parameters of structural-phase states and characteristics of short-term strength and ductility of vanadium alloys of V–4Ti–4Cr, V–2.4Zr–0.25C, V–1.2Zr–8.8Cr and V–1.7Zr–4.2Cr–7.6W systems with different concentration of interstitial elements after optimized thermomechanical treatment mode were summarized. It was shown that for effective realization of dispersion strengthening by Orowan-type mechanism at least 25–50% of the initial volume fraction of coarse particles should be transformed into fine-disperse state and redistributed over the volume of material

  20. Thermomechanical design of a static gas target for electron accelerators

    Brajuskovic, B; Holt, R J; Reneker, J; Meekin, D; Solvignon, P

    2013-01-01

    Gas targets are often used at accelerator facilities. A design of high-pressure gas cells that are suitable for hydrogen and helium isotopes at relatively high electron beam currents is presented. In particular, we consider rare gas targets, $^3$H$_2$ and $^3$He. In the design, heat transfer and mechanical integrity of the target cell are emphasized. ANSYS 12 was used for the thermo-mechanical studies of the target cell. Since the ultimate goal in this study was to design a gas target for use at the Jefferson Laboratory (JLab), particular attention is given to the typical operating conditions found there. It is demonstrated that an aluminum alloy cell can meet the required design goals.

  1. Standard practice for strain controlled thermomechanical fatigue testing

    American Society for Testing and Materials. Philadelphia

    2010-01-01

    1.1 This practice covers the determination of thermomechanical fatigue (TMF) properties of materials under uniaxially loaded strain-controlled conditions. A “thermomechanical” fatigue cycle is here defined as a condition where uniform temperature and strain fields over the specimen gage section are simultaneously varied and independently controlled. This practice is intended to address TMF testing performed in support of such activities as materials research and development, mechanical design, process and quality control, product performance, and failure analysis. While this practice is specific to strain-controlled testing, many sections will provide useful information for force-controlled or stress-controlled TMF testing. 1.2 This practice allows for any maximum and minimum values of temperature and mechanical strain, and temperature-mechanical strain phasing, with the restriction being that such parameters remain cyclically constant throughout the duration of the test. No restrictions are placed on en...

  2. Structural and Thermomechanical Properties of Stove Tile Ceramics

    Anton TRNÍK

    2013-12-01

    Full Text Available The thermomechanical and thermodilatometric behavior of fired heatproof stove tile ceramic material Letovice, which contains quartz, mullite and small amounts of feldspar and glassy phase, was studied while increasing temperature up to 1100 °C. Young’s modulus was measured using the non-destructive sonic resonant method mf-TMA. To find actual dimensions of the sample, thermodilatometry was carried out at the same temperature regime as mf-TMA. A significant increase in Young’s modulus was observed in the region of the α ® b transformation of quartz. This can be explained by the healing effect of the induced radial stresses around the quartz grains on microcracks. The presence of glassy phase caused a small decrease of Young’s modulus at temperatures above ~950 °C. DOI: http://dx.doi.org/10.5755/j01.ms.19.4.2916

  3. Potential of thermomechanical processing of dilute uranium alloys

    Preliminary results of studies on uranium-2.25 wt % niobium and uranium-0.75 wt % titanium suggest that thermomechanical processing of dilute uranium alloys might: (1) eliminate the need for quenching to obtain moderate yield strengths (approx. 900 MPa), (2) provide higher usable yield strengths (> 1050 MPa). Analysis of the stress-strain curve of annealed uranium-2.25% niobium indicates that deformation hardening should produce substantial increases in yield strength with very small decreases in ductility. Preliminary rolling experiments reveal that this material can be successfully warm worked over a wide range of conditions. Analysis of the stress-strain curve of solution treated uranium-0.75% titanium indicates that deformation hardening should produce better combinations of yield strength and ductility than can be obtained by age hardening. Preliminary rolliing experiments demonstrate that this alloy can be uniformly hardened at temperatures below 3000C and that the hardening effects of deformation and aging are approximately additive

  4. A self-sustaining micro thermomechanic-pyroelectric generator

    Ravindran, S. K. T.; Huesgen, T.; Kroener, M.; Woias, P.

    2011-09-01

    Pyroelectric generators (PEGs) can be used for thermal energy harvesting and present a potential alternative to thermoelectric generators. However, in contrary to thermoelectric generators, the PEG principle requires thermal transients to stimulate the conversion process. Such suitable thermal transients are rare in nature, hindering the deployment. In this paper, we present a micro thermomechanic-pyroelectric energy generator (μTMPG) that converts a stationary spatial thermal gradient into the required transient temperature profile across the PEG. The measured power output of the μTMPG is 3 μW from a temperature difference of 79.5 K. However, with an optimized design, a power output of 39.4 mW is estimated for the same temperature difference.

  5. Thermomechanical fatigue, oxidation, and Creep: Part II. Life prediction

    Neu, R. W.; Sehitoglu, Huseyin

    1989-09-01

    A life prediction model is developed for crack nucleation and early crack growth based on fatigue, environment (oxidation), and creep damage. The model handles different strain-temperature phasings (i.e., in-phase and out-of-phase thermomechanical fatigue, isothermal fatigue, and others, including nonproportional phasings). Fatigue life predictions compare favorably with experiments in 1070 steel for a wide range of test conditions and strain-temperature phasings. An oxide growth (oxide damage) model is based on the repeated microrupture process of oxide observed from microscopic measurements. A creep damage expression, which is stress-based, is coupled with a unified constitutive equation. A set of interrupted tests was performed to provide valuable damage progression information. Tests were performed in air and in helium atmospheres to isolate creep damage from oxidation damage.

  6. Mechanical and thermomechanical properties of polyamide 6/Brazilian organoclay nanocomposites

    Renê Anisio da Paz

    2016-02-01

    Full Text Available Abstract Polymer/clay nanocomposites are a new class of composites with polymer matrices where the disperse phase is a silicate with elementary particles that have at least one of dimensions in nanometer order. Polyamide 6/Brazilian organoclay nanocomposites were prepared by melt intercalation, and the mechanical, thermal and thermomechanical properties were studied. The structure and morphology of the nanocomposites were evaluated by X-ray diffraction (XRD and transmission electron microscopy (TEM. It was verified by XRD and TEM analysis that all systems presented exfoliated structure predominantly. By thermogravimetry (TG, nanocomposites showed higher stabilities in relation to pure polymer. It was observed that the nanocomposites showed better mechanical properties compared to the properties of polyamide 6. The heat deflection temperature (HDT values of the nanocomposites showed a significant increase in relation to pure polymer.

  7. On the thermomechanical deformation of silver shape memory nanowires

    Park, Harold S. [Department of Civil and Environmental Engineering, Vanderbilt University, VU Station B 351831, 2301 Vanderbilt Place, Nashville, TN 37235-1831 (United States)]. E-mail: harold.park@vanderbilt.edu; Ji, Changjiang [Department of Civil and Environmental Engineering, Vanderbilt University, VU Station B 351831, 2301 Vanderbilt Place, Nashville, TN 37235-1831 (United States)

    2006-06-15

    We present an analysis of the uniaxial thermomechanical deformation of single-crystal silver shape memory nanowires using atomistic simulations. We first demonstrate that silver nanowires can show both shape memory and pseudoelastic behavior, then perform uniaxial tensile loading of the shape memory nanowires at various deformation temperatures, strain rates and heat transfer conditions. The simulations show that the resulting mechanical response of the shape memory nanowires depends strongly upon the temperature during deformation, and can be fundamentally different from that observed in bulk polycrystalline shape memory alloys. The energy and temperature signatures of uniaxially loaded silver shape memory nanowires are correlated to the observed nanowire deformation, and are further discussed in comparison to bulk polycrystalline shape memory alloy behavior.

  8. Thermomechanical modeling of the Spent Fuel Test-Climax

    The Spent Fuel Test-Climax (SFT-C) was conducted to evaluate the feasibility of retrievable deep geologic storage of commercially generated spent nuclear-reactor fuel assemblies. One of the primary aspects of the test was to measure the thermomechanical response of the rock mass to the extensive heating of a large volume of rock. Instrumentation was emplaced to measure stress changes, relative motion of the rock mass, and tunnel closures during three years of heating from thermally decaying heat sources, followed by a six-month cooldown period. The calculations reported here were performed using the best available input parameters, thermal and mechanical properties, and power levels which were directly measured or inferred from measurements made during the test. This report documents the results of these calculations and compares the results with selected measurements made during heating and cooling of the SFT-C

  9. Thermo-Mechanical Analyses of Dynamically Loaded Rubber Cylinders

    Johnson, Arthur R.; Chen, Tzi-Kang

    2002-01-01

    Thick rubber components are employed by the Army to carry large loads. In tanks, rubber covers road wheels and track systems to protect roadways. It is difficult for design engineers to simulate the details of the hysteretic heating for large strain viscoelastic deformations. In this study, an approximation to the viscoelastic energy dissipated per unit time is investigated for use in estimating mechanically induced viscoelastic heating. Coupled thermo-mechanical simulations of large cyclic deformations of rubber cylinders are presented. The cylinders are first compressed axially and then cyclically loaded about the compressed state. Details of the algorithm and some computational issues are discussed. The coupled analyses are conducted for tall and short rubber cylinders both with and without imbedded metal disks.

  10. Thermomechanical and isothermal fatigue behavior of bare and coated superalloys

    Thermomechanical fatigue (TMF) and isothermal fatigue (IF) experiments were performed on bare Mar-M246 as well as bare and coated Mar-M247 nickel based superalloys at strain ranges from 0.335 to 1 percent. The experiments were conducted in air, through a temperature range of 500 to 1,038 C at a constant strain rate of 5.0 x 10-5 s-1. Due to the coarse-grained structure of Mar-M246, TMF lives scattered considerably under low strain range conditions. Electron microscopy studies show that significant surface oxidation and gamma prime, γ', depleted zones occur for Mar-M246 under these conditions. In the surface grain, where the change in γ' morphology is most pronounced, γ' rafted along axes ∼±45 deg from the loading axis. The influence of a protective coating on the IF and TMF lives of Mar-M247 was also examined. Results indicate that the coating does not significantly affect the fatigue lives of Mar-M247. The oxidation behavior of bare and coating Mar-M247 was investigated via X-ray microprobe and Auger Spectroscopy. Through these analyses, it is evident that the coating was completely degraded when exposed to the test environment for a long time. In both Mar-M246 and Mar-M247, in-phase thermomechanical fatigue (TMF IP) loading resulted in intergranular cracking. TMF IP loading promoted multiple cracks at the coating/substrate interface of coating Mar-M247. Finally, Eshelby techniques were used to calculate stress distributions in the vicinity of a surface oxide and second-phase particle at the coating/substrate interface

  11. On the numerical assessment of the thermo-mechanical performances of the DEMO Helium-Cooled Pebble Bed breeding blanket module

    Highlights: • HCPB blanket module thermo-mechanical behavior has been investigated under normal operation and over-pressurization steady state scenarios. • A theoretical–computational approach based on the finite element method (FEM) has been followed, adopting a qualified commercial FEM code. • Under normal operation scenario, SDC-IC safety rule relevant to the loss of ductility is not fulfilled in the FW and in the hot spots of SPv. • Under over-pressurization scenario, SDC-IC safety rule relevant to the loss of ductility is not met in the hot spots of lower and upper SPv. - Abstract: Within the framework of the European DEMO Breeder Blanket Programme, a research campaign has been launched by University of Palermo, ENEA-Brasimone and Karlsruhe Institute of Technology to theoretically investigate the thermo-mechanical behavior of the Helium-Cooled Pebble Bed (HCPB) breeding blanket module of the DEMO1 blanket vertical segment, under normal operation and over-pressurization loading scenarios. The research campaign has been carried out following a theoretical–computational approach based on the finite element method (FEM) and adopting a qualified commercial FEM code. A realistic 3D FEM model of the HCPB blanket module central poloidal–radial region has been developed, including one breeder cell in the toroidal direction and all the five cells in the poloidal one. No Breeder Units have been modeled, their presence being simulated by effective thermo-mechanical loads. Two sets of uncoupled steady state thermo-mechanical analyses have been carried out with reference to the investigated loading scenarios. In particular, under normal operation scenario (level A) the module has been supposed to undergo both 8 MPa coolant pressure on its cooling channel walls and thermal deformations due to the flat-top plasma operational state thermal field, while under over-pressurization scenario (level D) it has been assumed to experience 8 MPa coolant pressure on its

  12. Thermo-mechanical response and fatigue behavior of shape memory alloy

    Kusagawa, Masaki; Asada, Yasuhide; Nakamura, Toshiya [Tokyo Univ. (Japan). Dept. of Mechanical Engineering

    1998-11-01

    Mechanical, thermo-mechanical and fatigue behaviors of Ni-Ti-Nb shape memory alloy (SMA) have been studied to prepare material data for a design purpose. Presented are testing devices, testing procedure and test results of monotonic tensile, recovery of inelastic deformation due to post heating (thermo-mechanical recovery) and fatigue for future use of the SMA as a structural material of nuclear incore structures. (orig.)

  13. Thermo-mechanical modeling of plasterboard- lined partition submitted to fire load

    Sakji, S.; Soize, Christian; Heck, J.-V.

    2006-01-01

    An important problem is the development of a thermo-mechanical model of plasterboard lined partition submitted to fire load. A fundamental key to solve such a problem is the development and the experimental validation of a deterministic and a probabilistic thermo-mechanical model of cardboard-plaster-cardboard (CPC) submitted to fire load. The proposed model takes into account system parameter uncertainties and model uncertainties. The first part concerns the constitution of an experimental t...

  14. Evolution of Microstructure and Precipitation State during Thermomechanical Processing of a Low Carbon Microalloyed Steel

    Valles, P.; Gómez, Manuel; Medina, Sebastián F.; Pastor, A.; Vilanova, O.

    2012-01-01

    The increasing demand of sources of energy such as oil and natural gas induces at the steel industry a development on low carbon microalloyed steels for pipeline applications in order to achieve excellent mechanical properties of strength and toughness at a reduced cost. To obtain an adequate fine-grained final structure, the strict control of thermomechanical processing and accelerated cooling is crucial. Depending on the thermomechanical processing conditions and chemical composition, pipel...

  15. GaN-on-diamond electronic device reliability: Mechanical and thermo-mechanical integrity

    Liu, Dong; Sun, Huarui; Pomeroy, James W.; Francis, Daniel; Faili, Firooz; Twitchen, Daniel J.; Kuball, Martin

    2015-12-01

    The mechanical and thermo-mechanical integrity of GaN-on-diamond wafers used for ultra-high power microwave electronic devices was studied using a micro-pillar based in situ mechanical testing approach combined with an optical investigation of the stress and heat transfer across interfaces. We find the GaN/diamond interface to be thermo-mechanically stable, illustrating the potential for this material for reliable GaN electronic devices.

  16. GaN-on-diamond electronic device reliability: Mechanical and thermo-mechanical integrity

    The mechanical and thermo-mechanical integrity of GaN-on-diamond wafers used for ultra-high power microwave electronic devices was studied using a micro-pillar based in situ mechanical testing approach combined with an optical investigation of the stress and heat transfer across interfaces. We find the GaN/diamond interface to be thermo-mechanically stable, illustrating the potential for this material for reliable GaN electronic devices

  17. Mechanical properties of thermomechanical treated hyper-eutectic Al-Si-(Fe, Mn, Cu) materials

    Umezawa, Osamu

    2005-01-01

    Tensile and high-cycle fatigue behavior of thermomechanical treated hyper-eutectic Al-Si-(Fe, Mn, Cu) materials were studied. Through the repeated thermomechanical treatment (RTMT) which is a repeat of the multi steps cold-working followed by heat treatment, Si crystals and/or intermetallic compounds were broken into some fragments and dispersed in the aluminum matrix. Fine dispersion of the second phase particles exhibited good ductility, since early fracture was overcome. A few large Si cry...

  18. Thermo-mechanical response and fatigue behavior of shape memory alloy

    Mechanical, thermo-mechanical and fatigue behaviors of Ni-Ti-Nb shape memory alloy (SMA) have been studied to prepare material data for a design purpose. Presented are testing devices, testing procedure and test results of monotonic tensile, recovery of inelastic deformation due to post heating (thermo-mechanical recovery) and fatigue for future use of the SMA as a structural material of nuclear incore structures. (orig.)

  19. Simulation of thermo-mechanical effect in bulk-silicon FinFETs

    Burenkov, Alex; LORENZ, Jürgen

    2016-01-01

    The thermo-mechanical effect in bulk-silicon FinFETs of the 14 nm CMOS technology node is studied by means of numerical simulation. The electrical performance of such devices is significantly enhanced by the intentional introduction of mechanical stress during the device processing. The thermo-mechanical effect modifies the mechanical stress distribution in active regions of the transistors when they are heated. This can lead to a modification of the electrical performance. Numerical simulati...

  20. Multi-Fidelity Multidisciplinary Whole Engine Thermo-Mechanical Design Optimization

    Toal, David J.J.; Keane, Andy J; Benito, Diego; Dixon, Jeffery A.; Yang, Jingbin; Price, Matthew; Robinson, Trevor; Remouchamps, Alain; Kill, Norbert

    2014-01-01

    Traditionally, the optimization of a turbomachinery engine casing for tip clearance has involved either twodimensional transient thermomechanical simulations or three-dimensional mechanical simulations. This paper illustrates that three-dimensional transient whole-engine thermomechanical simulations can be used within tip clearance optimizations and that the efficiency of such optimizations can be improved when a multifidelity surrogate modeling approach is employed. These simulations are emp...

  1. The effects of short-lived radionuclides and porosity on the early thermo-mechanical evolution of planetesimals

    Lichtenberg, Tim; Golabek, Gregor J.; Gerya, Taras V.; Meyer, Michael R.

    2016-08-01

    The thermal history and internal structure of chondritic planetesimals, assembled before the giant impact phase of chaotic growth, potentially yield important implications for the final composition and evolution of terrestrial planets. These parameters critically depend on the internal balance of heating versus cooling, which is mostly determined by the presence of short-lived radionuclides (SLRs), such as 26Al and 60Fe, as well as the heat conductivity of the material. The heating by SLRs depends on their initial abundances, the formation time of the planetesimal and its size. It has been argued that the cooling history is determined by the porosity of the granular material, which undergoes dramatic changes via compaction processes and tends to decrease with time. In this study we assess the influence of these parameters on the thermo-mechanical evolution of young planetesimals with both 2D and 3D simulations. Using the code family I2ELVIS/I3ELVIS we have run numerous 2D and 3D numerical finite-difference fluid dynamic models with varying planetesimal radius, formation time and initial porosity. Our results indicate that powdery materials lowered the threshold for melting and convection in planetesimals, depending on the amount of SLRs present. A subset of planetesimals retained a powdery surface layer which lowered the thermal conductivity and hindered cooling. The effect of initial porosity was small, however, compared to those of planetesimal size and formation time, which dominated the thermo-mechanical evolution and were the primary factors for the onset of melting and differentiation. We comment on the implications of this work concerning the structure and evolution of these planetesimals, as well as their behavior as possible building blocks of terrestrial planets.

  2. Thermomechanical analysis of Natural Rubber behaviour stressed at room temperature.

    Chrysochoos A.

    2010-06-01

    Full Text Available Owing to their high molecular mobility, stressed rubber chains can easily change their conformations and get orientated. This phenomena leads to so high reversible draw ratio that this behaviour is called rubber elasticity [1-3]. The analogy with ideal gases leads to an internal energy independent of elongation, the stress being attributed to a so-called configuration entropy. However, this analysis cannot take thermal expansion into account and moreover prohibits predicting standard thermo-elastic effect noticed at small elongations and the thermoelastic inversion effects [4]. This paper aims at : observing and quantifying dissipative and coupling effects associated with deformation energy, generated when Natural Rubber is stretched. re-examine the thermomechanical behaviour model of rubberlike materials, under the generalised standard material concept. From an experimental viewpoint, energy balance is created using infrared and quantitative imaging techniques. Digital Image Correlation (DIC provides in-the-plane displacement fields and, after derivation, strain and strain-rate fields. We have used those techniques to evidence the thermoelastic inversion effect as shown on Figure 1 where different weights have been fixed to warmed specimen and we monitored the sample deformation while it recovers room temperature. But we have also used those techniques to perform energy balance : analysis of the mechanical equilibrium allows estimates of the stress pattern and computation of deformation energy rates under a plane stress hypothesis [5]. Infrared Thermography (IRT gives the surface temperature of the sample. To estimate the distribution of heat sources, image processing with a local heat equation and a minimal set of approximation functions (image filtering was used. The time courses of deformation energy and heat associated with cyclic process are plotted in Figure 2. The time derivatives of both forms of energy are approximately similar. This

  3. Speaking Code

    Cox, Geoff

    Speaking Code begins by invoking the “Hello World” convention used by programmers when learning a new language, helping to establish the interplay of text and code that runs through the book. Interweaving the voice of critical writing from the humanities with the tradition of computing and software...

  4. Code Cactus

    This code handles the following problems: -1) Analysis of thermal experiments on a water loop at high or low pressure; steady state or transient behavior; -2) Analysis of thermal and hydrodynamic behavior of water-cooled and moderated reactors, at either high or low pressure, with boiling permitted; fuel elements are assumed to be flat plates: - Flowrate in parallel channels coupled or not by conduction across plates, with conditions of pressure drops or flowrate, variable or not with respect to time is given; the power can be coupled to reactor kinetics calculation or supplied by the code user. The code, containing a schematic representation of safety rod behavior, is a one dimensional, multi-channel code, and has as its complement (FLID), a one-channel, two-dimensional code. (authors)

  5. Morphological features of retained austenite in thermo-mechanically processed C-Mn-Si-Al-Nb-Ti multiphase steel

    A. Grajcar

    2010-01-01

    Purpose: The aim of the paper is to determine the influence of isothermal bainitic transformation temperature on morphological features and a fraction of retained austenite in a new-developed thermo-mechanically processed C-Mn-Si-Al-Nb-Ti multiphase steel.Design/methodology/approach: The thermo-mechanical processing was realized in a multi-stage compression test by the use of the Gleeble thermomechanical simulator. The steel was isothermally held for 600 s in a bainitic transformation tempera...

  6. Long term thermomechanical stability of a spent fuel final repository located in granite at large depth

    The research program at INR Pitesti includes among other issues, the item of final disposal of the spent fuel from Cernavoda NPP. The heat release by the spent fuel and high radioactive waste leads to an increase of the temperature around each canister and in the granite rock. A series of processes such as canister's corrosion are dependent on the temperature. On the other hand, the temperature distribution inside the repository affects the stress and deformation state in different zones of the repository and implicitly its stability. The present work reports the results of a 3-D thermomechanical analysis carried out by means of ANSYS code for the final disposal of CANDU spent fuel from the Cernavoda NPP. The repository proposed consists in 72 parallel tunnels drilled in the granite rock at a 500 m depth. The spent fuel canisters are placed in parallel wells located at a 6 m distance from tunnel axis. The 3-D distribution of the temperature increase inside the repository after placing the fuel containers and tunnel closing are presented. The peak temperatures reached at the container's center and on its surface amount about 134 deg. C and 116 deg. C, respectively. These temperature values were reached at 25 years after containers' disposal inside the repository. Also, the stress distribution directly after excavation and after 25 years from containers' disposal was evaluated. The highest values of the axial stress were obtained in the canister's vicinity and at the tunnel ends. To evaluate the rock stability directly after excavation and at 25 years after containers' disposal the Hoek and Brown braking criterion was used

  7. Analysis of the thermo-mechanical deformations in a hot forging tool by numerical simulation

    L-Cancelos, R.; Varas, F.; Martín, E.; Viéitez, I.

    2016-03-01

    Although programs have been developed for the design of tools for hot forging, its design is still largely based on the experience of the tool maker. This obliges to build some test matrices and correct their errors to minimize distortions in the forged piece. This phase prior to mass production consumes time and material resources, which makes the final product more expensive. The forging tools are usually constituted by various parts made of different grades of steel, which in turn have different mechanical properties and therefore suffer different degrees of strain. Furthermore, the tools used in the hot forging are exposed to a thermal field that also induces strain or stress based on the degree of confinement of the piece. Therefore, the mechanical behaviour of the assembly is determined by the contact between the different pieces. The numerical simulation allows to analyse different configurations and anticipate possible defects before tool making, thus, reducing the costs of this preliminary phase. In order to improve the dimensional quality of the manufactured parts, the work presented here focuses on the application of a numerical model to a hot forging manufacturing process in order to predict the areas of the forging die subjected to large deformations. The thermo-mechanical model developed and implemented with free software (Code-Aster) includes the strains of thermal origin, strains during forge impact and contact effects. The numerical results are validated with experimental measurements in a tooling set that produces forged crankshafts for the automotive industry. The numerical results show good agreement with the experimental tests. Thereby, a very useful tool for the design of tooling sets for hot forging is achieved.

  8. Thermomechanical performance of the Eu TBMs under a typical Iter transient

    Six different breeding blanket concepts will be tested in ITER under the form of six different Test Blanket Modules (TBMs). In the frame of the activities of the European TBM Consortium of Associates the Helium Cooled Pebble Bed (HCPB-TBM) and the Helium Cooled Lithium Lead (HCLL) Test Blanket Modules are developed in Karlsruhe Institute of Technology (KIT) and in CEA Saclay respectively. For each EU TBM concept, four different TBMs will be installed into one dedicated ITER equatorial port and tested during different test campaigns. The main goal of the ITER TBM program is providing DEMO relevant experimental data for the three main functions of a blanket module of a future fusion reactor, namely removing heat, breeding tritium and shielding sensitive components from radiation. The two EU TBMs share a common external structure (the so called TBM box) while featuring a different internal design of the Breeder Units (BUs), reflecting the different breeding concept. The preliminary design assessment of the two TBMs boxes is based on nuclear analyses and on the evaluation of the power produced in the BU and deposed on the TBM box structures. The preliminary thermomechanical designs have been presented and are based on steady state analyses. The TBMs will work under ITER loads, i.e. cyclic loads defined by the typical ITER pulses. Transient thermal and mechanical analyses of the two EU TBMs under a typical ITER pulse are presented in this paper, identifying the main design issues related to structural behavior of the TBM box, codes and standard rules for assessing the TBM box integrity, TBM operational domain and related DEMO relevancy of the experimental campaign. Solutions to improve the weak structural points of the present designs are proposed, identifying the missing rules and the modelling development needs. (authors)

  9. Thermomechanical Analysis of Shape-Memory Composite Tape Spring

    Yang, H.; Wang, L. Y.

    2013-06-01

    Intelligent materials and structures have been extensively applied for satellite designs in order to minimize the mass and reduce the cost in the launch of the spacecraft. Elastic memory composites (EMCs) have the ability of high-strain packaging and shape-memory effect, but increase the parts and total weight due to the additional heating system. Shape-memory sandwich structures Li and Wang (J. Intell. Mater. Syst. Struct. 22(14), 1605-1612, 2011) can overcome such disadvantage by using the metal skin acting as the heating element. However, the high strain in the micro-buckled metal skin decreases the deployment efficiency. This paper aims to present an insight into the folding and deployment behaviors of shape-memory composite (SMC) tape springs. A thermomechanical process was analyzed, including the packaging deformation at an elevated temperature, shape frozen at the low temperature and shape recovery after reheating. The result shows that SMC tape springs can significantly decrease the strain concentration in the metal skin, as well as exhibiting excellent shape frozen and recovery behaviors. Additionally, possible failure modes of SMC tape springs were also analyzed.

  10. The development of heat exchangers with advanced thermomechanical materials

    Current metallurgical limitations necessarily impose a number of restrictions on the efficiency of power plant and combustion systems. These limitations include both temperature and corrosion resistance. If significant improvements can be made in these areas, then not only will it be possible to obtain higher system efficiencies, but it will also be possible to further exploit new technologies. Consequently, there is appreciable interest in the development of ceramic tubes for heat exchangers. Such tubes would offer the potential of operation at much higher temperatures combined with a much improved resistance to chemical attack. They are unlikely to be suitable for high pressure operation, at least in the foreseeable future, and hence their use would be limited generally to gas to gas exchangers. In spite of the limitations on details and specific technological solutions imposed by industrial property conditions, this report provides an overview on the development of these components, which is in charge of all the major international industrial companies of the field, in consideration of the relevant benefits coming from their large industrialization. After an analysis of the industrial situation of the product, in terms both of possible applications and economical impacts on the market, an overview of major on-going R and D programmes is carried out. At present, these programmes are mostly within the general frame of the study of advanced thermomechanical components and the related manufacturing technologies development

  11. Thermomechanical response of inhibited carbon-carbon composites

    Analytical models to capture the additional inhomogeneities such as boron carbide particulates added to enhance the oxidation resistance of carbon-carbon composites are developed. In parallel, the test results of laminates subjected to static and fatigue loading at ambient and high temperature (900 C) are monitored so that an interactive numerical simulation and observation procedure can be developed. The material system studied is HITCO 2D CC137EH, highly inhibited, eight harness satin weave, RT42 CVD SiC coated, carbon-carbon laminate. The static testing to date focuses on generating the upper bound loads to be used in the thermomechanical fatigue tests. The stress-strain response obtained from the static tension tests reveal a region of nonlinearity which is attributed to the presence of the porosity, the microcracking and the inhibitors. The significant number of oxidation tests of coated as well as partially uncoated specimens clearly indicate the preferential oxidation along the fiber bundles perpendicular to the exposed edges

  12. Progress with thermomechanical investigations of the Stripa site

    The Stripa mine in Sweden has provided an unusual opportunity to investigate the thermomechanical behavior of a granitic rock mass and the effect on such behavior of the discontinuities that are a persistent feature. Experiments to simulate the thermal effects of burying radioactive wastes have been carried out at a depth of about 340m. All of the thousands of underground measurements of temperatures, displacements, and stresses in the rock, recorded continuously over this period, have been made available on digital tape and in hard copy. This paper presents some results of recent investigations. Although temperature fields predicted by calculations based on linear heat conduction compare well with measured field data, evidence for some convective heat transfer has been found. Measured values of displacements have been significantly less than those predicted by calculations. Evidence that these displacements are diminished by fractures in the granite has been found. A program of laboratory investigations has been started to measure coefficients of thermal expansion and elastic moduli for Stripa granite. USAP (Underground Structural Analysis Program) is a unique finite element program that has been developed specifically for the analysis of underground structures; it has the potential to be used effectively in general problems associated with the underground storage of nuclear waste

  13. Progress in thermomechanical control of steel plates and their commercialization

    Kiyoshi Nishioka and Kazutoshi Ichikawa

    2012-01-01

    Full Text Available The water-cooled thermomechanical control process (TMCP is a technology for improving the strength and toughness of water-cooled steel plates, while allowing control of the microstructure, phase transformation and rolling. This review describes metallurgical aspects of the microalloying of steel, such as niobium addition, and discusses advantages of TMCP, for example, in terms of weldability, which is reduced upon alloying. Other covered topics include the development of equipment, distortions in steel plates, peripheral technologies such as steel making and casting, and theoretical modeling, as well as the history of property control in steel plate production and some early TMCP technologies. We provide some of the latest examples of applications of TMCP steel in various industries such as shipbuilding, offshore structures, building construction, bridges, pipelines, penstocks and cryogenic tanks. This review also introduces high heat-affected-zone toughness technologies, wherein the microstructure of steel is improved by the addition of fine particles of magnesium-containing sulfides and magnesium- or calcium-containing oxides. We demonstrate that thanks to ongoing developments TMCP has the potential to meet the ever-increasing demands of steel plates.

  14. Progress in thermomechanical control of steel plates and their commercialization

    The water-cooled thermomechanical control process (TMCP) is a technology for improving the strength and toughness of water-cooled steel plates, while allowing control of the microstructure, phase transformation and rolling. This review describes metallurgical aspects of the microalloying of steel, such as niobium addition, and discusses advantages of TMCP, for example, in terms of weldability, which is reduced upon alloying. Other covered topics include the development of equipment, distortions in steel plates, peripheral technologies such as steel making and casting, and theoretical modeling, as well as the history of property control in steel plate production and some early TMCP technologies. We provide some of the latest examples of applications of TMCP steel in various industries such as shipbuilding, offshore structures, building construction, bridges, pipelines, penstocks and cryogenic tanks. This review also introduces high heat-affected-zone toughness technologies, wherein the microstructure of steel is improved by the addition of fine particles of magnesium-containing sulfides and magnesium- or calcium-containing oxides. We demonstrate that thanks to ongoing developments TMCP has the potential to meet the ever-increasing demands of steel plates. (topical review)

  15. Thermomechanical fatigue behavior of Sn-Ag solder joints

    Choi, S.; Subramanian, K. N.; Lucas, J. P.; Bieler, T. R.

    2000-10-01

    Microstructural studies of thermomechanically fatigued actual electronic components consisting of metallized alumina substrate and tinned copper lead, soldered with Sn-Ag or 95.5Ag/4Ag/0.5Cu solder were carried out with an optical microscope and environmental scanning electron microscope (ESEM). Damage characterization was made on samples that underwent 250 and 1000 thermal shock cycles between -40°C and 125°C, with a 20 min hold time at each extreme. Surface roughening and grain boundary cracking were evident even in samples thermally cycled for 250 times. The cracks were found to originate on the free surface of the solder joint. With increased thermal cycles these cracks grew by grain boundary decohesion. The crack that will affect the integrity of the solder joint was found to originate from the free surface of the solder very near the alumina substrate and progress towards and continue along the solder region adjacent to the Ag3Sn intermetallic layer formed with the metallized alumina substrate. Re-examination of these thermally fatigued samples that were stored at room temperature after ten months revealed the effects of significant residual stress due to such thermal cycles. Such observations include enhanced surface relief effects delineating the grain boundaries and crack growth in regions inside the joint.

  16. Thermomechanical Impact of Polyurethane Potting on Gun Launched Electronics

    A. S. Haynes

    2013-01-01

    Full Text Available Electronics packages in precision guided munitions are used in guidance and control units, mission computers, and fuze-safe-and-arm devices. They are subjected to high g-loads during gun launch, pyrotechnic shocks during flight, and high g-loads upon impact with hard targets. To enhance survivability, many electronics packages are potted after assembly. The purpose of the potting is to provide additional structural support and shock damping. Researchers at the US Army recently completed a series of dynamic mechanical tests on a urethane-based potting material to assess its behavior in an electronics assembly during gun launch and under varying thermal launch conditions. This paper will discuss the thermomechanical properties of the potting material as well as simulation efforts to determine the suitability of this potting compound for gun launched electronics. Simulation results will compare stresses and displacements for a simplified electronics package with and without full potting. An evaluation of the advantages and consequences of potting electronics in munitions systems will also be discussed.

  17. Microstructure and Thermomechanical Properties of Magnesium Alloys Castings

    P. Lichý

    2012-04-01

    Full Text Available Magnesium alloys thanks to their high specific strength have an extensive potential of the use in a number of industrial applications. The most important of them is the automobile industry in particular. Here it is possible to use this group of materials for great numbers of parts from elements in the car interior (steering wheels, seats, etc., through exterior parts (wheels particularly of sporting models, up to driving (engine blocks and gearbox mechanisms themselves. But the use of these alloys in the engine structure has its limitations as these parts are highly thermally stressed. But the commonly used magnesium alloys show rather fast decrease of strength properties with growing temperature of stressing them. This work is aimed at studying this properties both of alloys commonly used (of the Mg-Al-Zn, Mn type, and of that ones used in industrial manufacture in a limited extent (Mg-Al-Sr. These thermomechanical properties are further on complemented with the microstructure analysis with the aim of checking the metallurgical interventions (an effect of inoculation. From the studied materials the test castings were made from which the test bars for the tensile test were subsequently prepared. This test took place within the temperature range of 20°C – 300°C. Achieved results are summarized in the concluding part of the contribution.

  18. Thermomechanical analyses of phenolic foam reinforced with glass fiber mat

    Highlights: • Over 10% glass fiber was used to reinforce phenolic foam in the shape of glass fiber mat. • Nucleating agents were used together with glass fiber mat and improved tensile strength of phenolic foam by 215.6%. • Nucleating agents lead to a smaller bubble size of phenolic foam. • The glass transition temperature of phenolic foam remained unchanged during the reinforcement. - Abstract: In this paper, thermomechanical analysis (TMA) and dynamic mechanical analysis were employed to study the properties of phenolic foam reinforced with glass fiber mat. Unreinforced phenolic foam was taken as the control sample. Mechanical tests and scanning electron microscopy were performed to confirm the results of TMA. The results show that glass fiber mat reinforcement improves the mechanical performance of phenolic foam, and nucleating agents improve it further. Phenolic foam reinforced with glass fiber mat has a smaller thermal expansion coefficient compared with unreinforced foam. The storage modulus of the reinforced phenolic foam is also higher than that in unreinforced foam, whereas the loss modulus of the former is lower than that of the latter. The glass transition temperature of the phenolic foam matrix remains unchanged during the reinforcement

  19. Micromechanisms of thermomechanical fatigue: A comparison with isothermal fatigue

    Bill, R. C.

    1986-01-01

    Thermomechanical Fatigue (TMF) experiments were conducted on Mar-M 200, B-1900, and PWA-1480 (single crystals) over temperature ranges representative of gas turbine airfoil environments. The results were examined from both a phenomenological basis and a micromechanical basis. Depending on constituents present in the superalloy system, certain micromechanisms dominated the crack initiation process and significantly influenced the TMF lives as well as sensitivity of the material to the type TMF cycle imposed. For instance, high temperature cracking around grain boundary carbides in Mar-M 200 resulted in short in-phase TMF lives compared to either out-of-phase or isothermal lives. In single crystal PWA-1480, the type of coating applied was seen to be the controlling factor in determining sensitivity to the type of TMF cycle imposed. Micromechanisms of deformation were observed over the temperature range of interest to the TMF cycles, and provided some insight as to the differences between TMF damage mechanisms and isothermal damage mechanisms. Finally, the applicability of various life prediction models to TMF results was reviewed. Current life prediction models based on isothermal data must be modified before being generally applied to TMF.

  20. Low cycle fatigue behavior of thermo-mechanically treated rebar

    Highlights: • Strain and stress controlled low cycle fatigue behavior of TMT rebar. • Decrease in the cyclic yield stress is responsible for cyclic softening of TMT rebar. • Fatigue crack initiates form the transverse rib root and propagate along the same region. • Stress concentration and high stress triaxiality observed at the root of the transverse rib. - Abstract: The strain and stress controlled low cycle fatigue behavior of thermo-mechanically treated rebar are examined in this current work at room temperature. Severe cyclic softening is observed in all applied strain amplitudes during strain controlled low cycle fatigue. Cyclic softening deteriorates the seismic resistance property of the rebar. Decrease in the cyclic yield stress (linear portion of the hysteresis loop) is responsible for cyclic softening. Cyclic softening results progressive opening up the hysteresis loop during stress controlled low cycle fatigue. It is experimentally observed that irrespective of control mode (stress/strain) and loading conditions, fatigue crack initiates form the transverse rib root and propagate along the same region. Finite element simulation result reveal that stress concentration takes place at the root of the transverse rib and stress triaxiality become higher in the same region. Tensile strain accumulation at the transverse rib root is detected in simulation. Simulation result explains the experimental fact that fatigue crack initiate and propagate along the transverse rib root

  1. The AMP (Advanced MultiPhysics) Nuclear Fuel Performance code

    Highlights: ► New, three-dimensional, parallel, multi-physics code to simulate fuel behavior in nominal operation. ► Fully-coupled thermomechanics for nominal operation and operation during transients. ► Isotopic depletion using Scale/ORIGEN-S within a fuel performance code. ► Leveraging of existing, validated material models from existing fuel performance codes. ► Initial validation evaluation of an advanced modeling and simulation code for fuel performance. - Abstract: The AMP (Advanced MultiPhysics) Nuclear Fuel Performance code is a new, three-dimensional, multi-physics tool that uses state-of-the-art solution methods and validated nuclear fuel models to simulate the nominal operation and anticipated operational transients of nuclear fuel. The AMP Nuclear Fuel Performance code leverages existing validated material models from traditional fuel performance codes and the Scale/ORIGEN-S spent-fuel characterization code to provide an initial capability that is shown to be sufficiently accurate for a single benchmark problem and anticipated to be accurate for a broad range of problems. The thermomechanics foundation can be solved in a time-dependent or quasi-static approach with any variation of operator-split or fully-coupled solutions at each time step through interoperable interfaces to leading computational mathematics tools, including PETSc, Trilinos, and SUNDIALS. A baseline validation of the AMP Nuclear Fuel Performance code has been performed through the modeling of an experiment in the Halden Reactor Project (IFA-432) that demonstrates the integrated capability and provides a baseline of the initial accuracy of the software.

  2. Free Vibration Analysis for Layered Shells Accounting of Variable Kinematic and Thermo-Mechanical Coupling

    S. Brischetto

    2012-01-01

    Full Text Available The free vibration analysis of one-layered and two-layered metallic cylindrical shell panels is evaluated in this work. The free frequency values are investigated for both thermo-mechanical and pure mechanical problems. Thermo-mechanical frequencies are calculated by means of a fully coupled thermo-mechanical model where both the displacement and temperature are primary variables in the considered governing equations. Pure mechanical frequencies are obtained from a mechanical model where the effect of the temperature field is not included in the stiffness matrix and the displacement is the only primary variable of the problem. The inclusion of the thermal part in the stiffness matrix gives larger frequencies. Both thermo-mechanical and pure mechanical models are developed in the framework of Carrera's Unified Formulation (CUF in order to obtain several variable kinematic models. Both equivalent single layer and layer wise approaches are considered for multilayered shells. The use of refined two-dimensional theories for shells permits the evaluation of the effects of the thermo-mechanical coupling for lower and higher order modes, higher frequency values, multilayered configurations, thick and thin shells and several values of the radius of curvature of the shell geometry. It has mainly been concluded that the thermo-mechanical coupling is not influenced by the curvature of the shells, therefore, the main conclusions already given for the plate geometry are here confirmed: – the thermo-mechanical coupling is correctly determined if both the thermal and mechanical parts are correctly approximated; – it is small for each investigated case; – it influences the various vibration modes in different ways; – it has a limited dependence on the considered case, but this dependence vanishes if a global coupling is considered.

  3. The effect of beam interruptions on the integrity of ADSR fuel pin cladding: A thermo-mechanical analysis

    Highlights: ► We present beam interruption data for four high power proton accelerators. ► We extend the PTS-ADS code capabilities to include a thermal stress Subroutine. ► We study the thermo-mechanical response in an ADSR cladding to unplanned beam interruptions. ► We perform a thermal fatigue analysis. ► The cladding integrity is severely affected if the current accelerator technology is deployed. - Abstract: During its lifetime in the core, the cladding of an Accelerator Driven Subcritical Reactor (ADSR) fuel pin is expected to experience variable stresses due to frequent interruptions in the accelerator proton beam. This paper investigates the thermal fatigue damage in the cladding due to repetitive and unplanned beam interruptions under certain operational conditions. Beam trip data was obtained for four operating high power proton accelerators, among which the Spallation Neutron Source (SNS) superconducting accelerator was selected for further analysis. 9Cr–1Mo–Nb–V (T91) steel was selected as the cladding material because of its proven compatibility with proposed ADSR design concepts. The neutronic, thermal and stress analyses were performed using the PTS-ADS, a code that has been specifically developed for studying the dynamic response to beam-induced transients in accelerator driven subcritical systems. The lifetime of the fuel cladding in the core was estimated for three levels of allowed pin power and specific operating conditions.

  4. Thermomechanical evaluation of BWR fuel elements for procedures of preconditioned with FEMAXI-V; Evaluacion termomecanica de elementos combustible BWR para procedimientos de preacondicionado con FEMAXI-V

    Hernandez L, H.; Lucatero, M.A.; Ortiz V, J. [ININ, Carretera Mexico-Toluca Km 36.5, La Marquesa, Estado de Mexico (Mexico)]. e-mail: hhl@nuclear.inin.mx

    2006-07-01

    The limitations in the burnt of the nuclear fuel usually are fixed by the one limit in the efforts to that undergo them the components of a nuclear fuel assembly. The limits defined its provide the direction to the fuel designer to reduce to the minimum the fuel failure during the operation, and they also prevent against some thermomechanical phenomena that could happen during the evolution of transitory events. Particularly, a limit value of LHGR is fixed to consider those physical phenomena that could lead to the interaction of the pellet-shirt (Pellet Cladding Interaction, PCI). This limit value it is related directly with an PCI limit that can be fixed based on experimental tests of power ramps. This way, to avoid to violate the PCI limit, the conditioning procedures of the fuel are still required for fuel elements with and without barrier. Those simulation procedures of the power ramp are carried out for the reactor operator during the starting maneuvers or of power increase like preventive measure of possible consequences in the thermomechanical behavior of the fuel. In this work, the thermomechanical behavior of two different types of fuel rods of the boiling water reactor is analyzed during the pursuit of the procedures of fuel preconditioning. Five diverse preconditioning calculations were carried out, each one with three diverse linear ramps of power increments. The starting point of the ramps was taken of the data of the cycle 8 of the unit 1 of the Laguna Verde Nucleo electric Central. The superior limit superior of the ramps it was the threshold of the lineal power in which a fuel failure could be presented by PCI, in function of the fuel burnt. The analysis was carried out with the FEMAXI-V code. (Author)

  5. 基于ABAQUS的钢轨铝热焊接接头的有限元分析%The Finite Element Analysis of Rail Thermite Welding Joint on ABAQUS

    侯健

    2013-01-01

    A finite element model of rail welding joint is built with the finite element software ABAQUS,and the ABAQUS is used to analyze the mechanical properties of rail thermite welding joint under the pure rolling condition and pure sliding contion.Then basing on the analysis of the pure rolling wheel-rail contact,study the influence of the performance parameters such as speed of train,position of welding joint,width of welding zone.The results show that the sliding wheel-rail contact do harm to welding joint,the speed of train,positionof welding joint and width of welding zone has considerable effects on the mechanical properties of welding joints.%运用有限元软件ABAQUS强大的处理功能建立了钢轨铝热焊接接头弹塑性分析的有限元模型,并在此基础上进行轮轨纯滚动接触和全滑动接触两种工况下的焊接接头力学性能分析;然后在纯滚动接触的基础上,研究各项性能参数如车速、焊接接头位置、焊缝热影响区宽度、接头不平顺及波深等的影响.结果表明,轮轨滑动接触对接头损伤较大,车速、焊接接头位置、焊缝热影响区宽度对焊接接头力学性能有重要影响.

  6. Fe Simulation of Cutting Status when High Speed Machining the Ti-6Al-4V Based on Abaqus%基于ABAQUS高速切削Ti-6Al-4V切削状态的有限元仿真

    冯吉路; 姜增辉

    2013-01-01

    A high speed orthogonal cutting Ti-6AMV of Johnson-Cook materials model and fracture criterion was established by Abaqus/Explicit. The influence of cutting speed, cutting depth, tool rake angel on the average cutting force and the chip morphology was discussed respectively. The investigation indicate that serrated degree of chips and teeth space was increased when increasing cutting speed and cutting depth, while tool rake angel is just the opposite. And the average cutting force was steadied during the cutting speed coming up to 60m/min-180m/min, it was increased with the increase of cutting depth, cutting force decreased with the increase of tool rake angel.%文章基于Abaqus/Explicit的Johnson-Cook材料模型以及断裂准则模拟高速正交切削Ti-6Al-4V,仿真分析了切削速度、切削深度、刀具前角变化时对平均切削力以及锯齿状切屑形态的影响.研究结果表明:切屑锯齿化程度和齿距随切削速度和切削深度的增加而增大,随前角的增加而减小.平均切削力在切削速度为60m/min-180m/min时趋于平稳,随切削深度增加而增大,随前角增大而减小.

  7. RAPTA-5 code: Modelling behaviour of WWER-type fuel rods in design basis accidents verification calculations

    RAPTA-5 code used for licensing calculations to validate the compliance with the requirements for WWER fuel safety in design basis accidents. The characteristic results are given of design modelling experiments simulating thermomechanical and corrosion behaviour of WWER and PWR fuel rods in LOCA. The results corroborate the adequate predictability of both individual design models and the code as a whole. (author). 14 refs, 12 figs

  8. Optimal codes as Tanner codes with cyclic component codes

    Høholdt, Tom; Pinero, Fernando; Zeng, Peng

    2014-01-01

    In this article we study a class of graph codes with cyclic code component codes as affine variety codes. Within this class of Tanner codes we find some optimal binary codes. We use a particular subgraph of the point-line incidence plane of A(2,q) as the Tanner graph, and we are able to describe ...

  9. Speech coding

    Ravishankar, C., Hughes Network Systems, Germantown, MD

    1998-05-08

    Speech is the predominant means of communication between human beings and since the invention of the telephone by Alexander Graham Bell in 1876, speech services have remained to be the core service in almost all telecommunication systems. Original analog methods of telephony had the disadvantage of speech signal getting corrupted by noise, cross-talk and distortion Long haul transmissions which use repeaters to compensate for the loss in signal strength on transmission links also increase the associated noise and distortion. On the other hand digital transmission is relatively immune to noise, cross-talk and distortion primarily because of the capability to faithfully regenerate digital signal at each repeater purely based on a binary decision. Hence end-to-end performance of the digital link essentially becomes independent of the length and operating frequency bands of the link Hence from a transmission point of view digital transmission has been the preferred approach due to its higher immunity to noise. The need to carry digital speech became extremely important from a service provision point of view as well. Modem requirements have introduced the need for robust, flexible and secure services that can carry a multitude of signal types (such as voice, data and video) without a fundamental change in infrastructure. Such a requirement could not have been easily met without the advent of digital transmission systems, thereby requiring speech to be coded digitally. The term Speech Coding is often referred to techniques that represent or code speech signals either directly as a waveform or as a set of parameters by analyzing the speech signal. In either case, the codes are transmitted to the distant end where speech is reconstructed or synthesized using the received set of codes. A more generic term that is applicable to these techniques that is often interchangeably used with speech coding is the term voice coding. This term is more generic in the sense that the

  10. An anisotropic thermomechanical damage model for concrete at transient elevated temperatures.

    Baker, Graham; de Borst, René

    2005-11-15

    The behaviour of concrete at elevated temperatures is important for an assessment of integrity (strength and durability) of structures exposed to a high-temperature environment, in applications such as fire exposure, smelting plants and nuclear installations. In modelling terms, a coupled thermomechanical analysis represents a generalization of the computational mechanics of fracture and damage. Here, we develop a fully coupled anisotropic thermomechanical damage model for concrete under high stress and transient temperature, with emphasis on the adherence of the model to the laws of thermodynamics. Specific analytical results are given, deduced from thermodynamics, of a novel interpretation on specific heat, evolution of entropy and the identification of the complete anisotropic, thermomechanical damage surface. The model is also shown to be stable in a computational sense, and to satisfy the laws of thermodynamics. PMID:16243703

  11. Effect of Thermo-mechanical Treatment on Mechanical Properties of Korean RAFM steel

    Kim, M. S.; Chun, Y. B.; Lee, D. W.; Lee, C. K. [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of); Cho, S. Y. [National Fusion Research Institute, Daejeon (Korea, Republic of)

    2015-05-15

    Advanced reduced-activation alloy (ARAA) of Korean RAFM steels was developed by Korea Atomic Energy Research Institute (KAERI) and National Fusion Research Institute (NFRI). Thermo-mechanical treatment (TMT) has been known to be effective to improvement in mechanical properties of several RAFM steels by introducing high densities of dislocations and fine precipitates. This study examines the effect of thermo-mechanical treatment on the microstructure and mechanical properties of ARAA alloy. The effects of thermo-mechanical treatment on microstructure and mechanical properties were studied. TMT consisting of austenitizing and 20% hot-rolling at 700 .deg. C significantly enhances both tensile strength and impact property of ARAA, which suggests that a TMT is a promising way of improving mechanical properties of RAFM steels.

  12. The temperature memory effect and the influence of thermo-mechanical cycling in shape memory alloys

    Apart from the well-known shape memory effect (SME), the temperature memory effect (TME), i.e., the ability of a material to remember the heating interrupted temperature in the previous thermal cycle, is another interesting phenomenon observed in many shape memory alloys (SMAs). In this paper, based on previous and current experimental observations, we propose a phenomenological model to reproduce the TME. Subsequently, we study the influence of thermo-mechanical cycling (uniaxial tension) on the TME in a polycrystalline NiTi SMA wire (0.51 mm diameter). The maximum tensile strain in each cycle is 10%, which is beyond its elastic limit. The evolution of the peak transition temperature in the forward and reverse transformations and the TME upon thermo-mechanical cycling is investigated by differential scanning calorimetry. It is proved that the TME is a stable intrinsic phenomenon and can be utilized even under severe thermo-mechanical conditions

  13. Effect of Thermo-mechanical Treatment on Mechanical Properties of Korean RAFM steel

    Advanced reduced-activation alloy (ARAA) of Korean RAFM steels was developed by Korea Atomic Energy Research Institute (KAERI) and National Fusion Research Institute (NFRI). Thermo-mechanical treatment (TMT) has been known to be effective to improvement in mechanical properties of several RAFM steels by introducing high densities of dislocations and fine precipitates. This study examines the effect of thermo-mechanical treatment on the microstructure and mechanical properties of ARAA alloy. The effects of thermo-mechanical treatment on microstructure and mechanical properties were studied. TMT consisting of austenitizing and 20% hot-rolling at 700 .deg. C significantly enhances both tensile strength and impact property of ARAA, which suggests that a TMT is a promising way of improving mechanical properties of RAFM steels

  14. Semi-analytical solution of time-dependent thermomechanical creep behavior of FGM hollow spheres

    Jafari Fesharaki, J.; Loghman, A.; Yazdipoor, M.; Golabi, S.

    2014-02-01

    By using a method of successive elastic solution, the time-dependent creep behavior of a functionally graded hollow sphere under thermomechanical loads has been investigated. Based on volume percentage, the mechanical and thermal properties of material, except for the Poisson's ratio, are assumed to be radially dependent. Total strains are assumed to be the sum of elastic, thermal and creep strains. Creep strains are temperature-, stress- and time-dependent. Using the Prandtl-Reuss relations and Sherby's law, histories of stresses and strains are presented from their initial elastic values at zero time up to 30 years after loading. The results show that the creep stresses and strains change with time and material inhomogeneity has influence on thermomechanical creep behavior. The aim of this work was to understand the effect of creep behavior on a functionally graded hollow sphere subjected to thermomechanical load.

  15. NSURE code

    NSURE stands for Near-Surface Repository code. NSURE is a performance assessment code. developed for the safety assessment of near-surface disposal facilities for low-level radioactive waste (LLRW). Part one of this report documents the NSURE model, governing equations and formulation of the mathematical models, and their implementation under the SYVAC3 executive. The NSURE model simulates the release of nuclides from an engineered vault, their subsequent transport via the groundwater and surface water pathways tot he biosphere, and predicts the resulting dose rate to a critical individual. Part two of this report consists of a User's manual, describing simulation procedures, input data preparation, output and example test cases

  16. Improvement of thermo-mechanical properties of ceramic materials for nuclear applications

    In order to improve the thermo-mechanical properties of materials used as neutron absorbers in nuclear reactors, cermet or cercer have been produced with two original microstructures: micro- or macro-dispersed composites. The composites thermal shock resistance has been evaluated in an image furnace. The microstructures we obtained involve different reinforcement mechanisms, such as crack deflection, crack branching, crack bridging or microcrack toughening, and improvement of thermal conductivity. The results reveal a significant improvement of the thermo-mechanical properties of the boron base neutron absorbers whose fabrication process leads to a macro-dispersed microstructure. (authors). 8 refs., 8 figs., 2 tabs

  17. Thermomechanical simulation of the selective laser melting process for PA12 including volumetric shrinkage

    Riedlbauer, D.; Steinmann, P.; Mergheim, J.

    2015-05-01

    The present contribution is concerned with the finite element simulation of the thermomechanical material behavior in the selective laser melting process for PA12. In the process shrinkage of the powder material is observed when becoming melt, as the porous character of the powder vanishes due to the phase transition. A nonlinear thermomechanical finite element model is developed, which captures the shrinkage of the material and includes temperature dependent material parameters. The model is used to simulate the shrinkage of the material in the process, where an adaptive mesh refinement is applied for increasing the accuracy of the simulation. The results are qualitatively compared with experimental data and show a good agreement.

  18. Obtaining an Acicular Microstructure by Thermomechanical Sequences in X-80 Steel

    de Castro, Renato Soares; Pedrosa, Igor Rafael Vilarouco; Yadava, Yogendra Prasad; Ferreira, Ricardo Artur Sanguinetti

    2014-09-01

    Microstructural modification is one of the routes to increase strength and toughness in high-strength low-alloy (HSLA) steels. Considering the good mechanical properties of acicular ferrite, thermomechanical sequences, with continuous cooling or isothermal treatment, were applied in an X-80 HSLA steel to obtain dominant acicular microstructure. Electron microscopy and electron back-scattered diffraction (EBDS) analyses were performed to identify and quantify microstructural changes. It was possible to correlate the misorientation boundaries profile with the occurrence of acicular microstructure, which was characterized by a high quantity of substructured and deformed units. Thermomechanical sequences with continuous cooling were more effective for obtaining acicular microstructure than sequences of isothermal treatments.

  19. Influence of thermomechanical aging on fatigue behaviour of 2014 Al-alloy

    S Singh; D B Goel

    2005-04-01

    The fatigue behaviour of 2014 Al-alloy has been studied in various thermomechanically aged conditions. It is observed that fatigue properties can be improved by a thermomechanical treatment, which would reduce the concentrations of dispersoids, provide a relatively uniform deformation structure and produce fine distribution of ' precipitates. Fine ' particles inhibit dynamic recovery and produce uniform deformation structure, which improves fatigue behaviour. Presence of dispersoids and coarse precipitate particles leads to the formation of persistent slip bands (PSBs) and a highly heterogeneous deformation structure, which cause damage to fatigue properties.

  20. Thermomechanical and Environmental Durability of Environmental Barrier Coated Ceramic Matrix Composites Under Thermal Gradients

    Zhu, Dongming; Bhatt, Ramakrishna T.; Harder, Bryan

    2016-01-01

    This paper presents the developments of thermo-mechanical testing approaches and durability performance of environmental barrier coatings (EBCs) and EBC coated SiCSiC ceramic matrix composites (CMCs). Critical testing aspects of the CMCs will be described, including state of the art instrumentations such as temperature, thermal gradient, and full field strain measurements; materials thermal conductivity evolutions and thermal stress resistance; NDE methods; thermo-mechanical stress and environment interactions associated damage accumulations. Examples are also given for testing ceramic matrix composite sub-elements and small airfoils to help better understand the critical and complex CMC and EBC properties in engine relevant testing environments.

  1. The Aster code; Code Aster

    Delbecq, J.M

    1999-07-01

    The Aster code is a 2D or 3D finite-element calculation code for structures developed by the R and D direction of Electricite de France (EdF). This dossier presents a complete overview of the characteristics and uses of the Aster code: introduction of version 4; the context of Aster (organisation of the code development, versions, systems and interfaces, development tools, quality assurance, independent validation); static mechanics (linear thermo-elasticity, Euler buckling, cables, Zarka-Casier method); non-linear mechanics (materials behaviour, big deformations, specific loads, unloading and loss of load proportionality indicators, global algorithm, contact and friction); rupture mechanics (G energy restitution level, restitution level in thermo-elasto-plasticity, 3D local energy restitution level, KI and KII stress intensity factors, calculation of limit loads for structures), specific treatments (fatigue, rupture, wear, error estimation); meshes and models (mesh generation, modeling, loads and boundary conditions, links between different modeling processes, resolution of linear systems, display of results etc..); vibration mechanics (modal and harmonic analysis, dynamics with shocks, direct transient dynamics, seismic analysis and aleatory dynamics, non-linear dynamics, dynamical sub-structuring); fluid-structure interactions (internal acoustics, mass, rigidity and damping); linear and non-linear thermal analysis; steels and metal industry (structure transformations); coupled problems (internal chaining, internal thermo-hydro-mechanical coupling, chaining with other codes); products and services. (J.S.)

  2. Beyond Stabilizer Codes II: Clifford Codes

    Klappenecker, Andreas; Roetteler, Martin

    2000-01-01

    Knill introduced a generalization of stabilizer codes, in this note called Clifford codes. It remained unclear whether or not Clifford codes can be superior to stabilizer codes. We show that Clifford codes are stabilizer codes provided that the abstract error group has an abelian index group. In particular, if the errors are modelled by tensor products of Pauli matrices, then the associated Clifford codes are necessarily stabilizer codes.

  3. MCNP code

    The MCNP code is the major Monte Carlo coupled neutron-photon transport research tool at the Los Alamos National Laboratory, and it represents the most extensive Monte Carlo development program in the United States which is available in the public domain. The present code is the direct descendent of the original Monte Carlo work of Fermi, von Neumaum, and Ulam at Los Alamos in the 1940s. Development has continued uninterrupted since that time, and the current version of MCNP (or its predecessors) has always included state-of-the-art methods in the Monte Carlo simulation of radiation transport, basic cross section data, geometry capability, variance reduction, and estimation procedures. The authors of the present code have oriented its development toward general user application. The documentation, though extensive, is presented in a clear and simple manner with many examples, illustrations, and sample problems. In addition to providing the desired results, the output listings give a a wealth of detailed information (some optional) concerning each state of the calculation. The code system is continually updated to take advantage of advances in computer hardware and software, including interactive modes of operation, diagnostic interrupts and restarts, and a variety of graphical and video aids

  4. ANIMAL code

    This report describes ANIMAL, a two-dimensional Eulerian magnetohydrodynamic computer code. ANIMAL's physical model also appears. Formulated are temporal and spatial finite-difference equations in a manner that facilitates implementation of the algorithm. Outlined are the functions of the algorithm's FORTRAN subroutines and variables

  5. Thermo-mechanical phenomena in high speed continuous casting processes

    Park, Joong Kil

    Thermo-mechanical phenomena during continuous thin slab casting have been studied with the objectives of understanding the mechanism of mold crack formation, and the effect of mold design upon the mechanical behavior of the stand. To achieve these goals, several finite element models have been developed in conjunction with a series of industrial plant trials. First, an investigation of mold crack formation in thin slab casting was undertaken to elucidate the mechanism by which cracks develop and to evaluate possible solutions to the problem. Three-dimensional finite-element thermal-stress models were developed to predict temperature, distortion, and residual stress in thin-slab casting molds, comparing funnel-shaped to parallel molds. Mold wall temperatures were obtained from POSCO in Korea and analyzed to determine the corresponding heat-flux profiles in thin-slab molds. This data was utilized in an elastic-visco-plastic analysis to investigate the deformation of the molds in service for the two different mold shapes. The results of a metallurgical investigation of mold samples containing cracks were used together with the results of the mathematical models, to determine mechanisms and to suggest solutions for the formation of mold cracks. Large cyclic inelastic strains were found in the funnel transition region just below the meniscus, due to the slightly higher temperature at that location. The cracks appear to have propagated by thermal fatigue caused by major level fluctuations. Next, two-dimensional thermo-elastic-visco-plastic analysis was performed for a horizontal slice of the solidifying strand, which moves vertically down the mold during casting. The model calculates the temperature distributions, the stresses and the strains in the solidifying shell, and the air gap between the casting mold and the solidifying strand. Model predictions were verified with an analytical solution and plant trials that were carried out during billet casting at POSCO. The

  6. 基于ABAQUS强度折减法某铀尾矿坝稳定性分析%The Analysis of a Uranium Tailings Dam Stability Based on ABAQUS Strength Reduction Method

    周薛淼; 刘永; 李国辉; 卢继鹰

    2016-01-01

    From the combination of the finite software of ABAQUS and strength reduction method,making full use of powerful post-processing ability of ABAQUS,this study analyzes a uranium tailings dam stability.The displacement mutation of slope feature control points and plastic zone breakthrough of slipping plane from the dam slope toe to top are used as a sym-bol of the whole slope instability.When plastic zone in the slope sliding surface is connected from the slope toe to top, plastic strain and displacement of characteristic control points result in mutation,the dam slope is in a critical state of sliding failure,while the strength re-duction factor is defined as the minimum safety coefficient of dam slope stability.Through an example of a uranium tailings dam stability analysis, it can predict accurately and vividly dam slope potential sliding surface position and evaluate the stability of dam slop,especially for the stability analysis of complex terrain slope,which is a simple and practicable method.%将ABAQUS有限元软件和强度折减法相结合,充分利用ABAQUS的强大后处理能力对某一铀尾矿坝稳定性进行分析。通过把坡面的特征控制点的位移突变和滑移面塑性区从坡脚到坡顶的贯通作为边坡整体失稳的标志,当滑移面的塑性区贯通,塑性应变和特征控制点的位移发生突变时,则坝坡就处于滑动破坏临界状态,而此时的强度折减系数就定义为坝坡稳定的最小安全系数。通过某铀尾矿坝稳定性分析的实例,可以准确形象的预测出坝潜在坡滑动面的位置和评价坝坡的稳定性,尤其对地形复杂的边坡稳定性分析简单适用。

  7. Thermo-mechanical analysis for determining the optimum design of a deposition hole using FLAC3D

    In this study, the vertical location of canister in a deposition hole was determined from the thermo-mechanical coupling analysis using the three-dimensional finite difference code, FLAC3D. A FISH program was made and used for the modeling for different conditions. The following conclusions could be drawn from the study. (1) The canister moves downward initially, but moves upward with time due to the thermal expansion of buffer. (2) The tunnel floor above the deposition hole remains elastic until 100 years after the emplacement of the canister if the top buffer thickness is more than 1.5 m. (3) It was found that the peak temperature decreases with the increase of the buffer and backfill thickness, when backfilling is done immediately after the emplacement. (4) Without swelling pressure, the maximum tensile stress is up to 18 MPa at 100 days after the emplacement. Since the swelling pressure from the buffer confines the thermal expansion of the canister, the mechanical stability of canister is improved with the swelling pressure. (5) When the air temperature in the tunnels is maintained at 27 .deg. C by ventilation, the peak temperature with delayed backfilling for 50 years is about 75 .deg. while it is over 90 .deg. with immediately backfilling. (6) The buffer and backfill thickness above the canister in a deposition hole should be at least 2 m based on literature review and the computer simulations

  8. Thermomechanical room and canister region benchmark analyses between STEALTH-WI and SPECTROM-32: Draft final report

    This report documents the benchmarking of the two-dimensional waste isolation version of STEALTH (designated STEALTH-WI) against the thermomechanical performance assessment calculations performed by RE/SPEC using SPECTROM-32. An axisymmetric, canister-scale (very-near-field) analysis was performed to compute the peak stress exerted by the salt on the waste package. A plane strain, room-scale (near-field) analysis was also performed to predict disposal room roof-to-floor closure and the temperatures at key locations in the vicinity of the disposal room. Comparisons between the STEALTH and SPECTROM-32 results showed that the temperature predictions agreed to within 5/degree/C, peak canister stresses better than 10%, and the average roof-to-floor closures within 30%. The stress and displacement differences were attributed to differences in the treatment of plasticity in the constitutive laws for salt employed in STEALTH and SPECTROM-32. The temperature differences were due to minor differences in the thermal models employed in STEALTH and SPECTROM- 41, the thermal analysis code which supplies temperatures for SPECTROM-32. 9 refs., 21 figs., 6 tabs

  9. The effects of short-lived radionuclides and porosity on the early thermo-mechanical evolution of planetesimals

    Lichtenberg, Tim; Gerya, Taras V; Meyer, Michael R

    2016-01-01

    The thermal history and internal structure of chondritic planetesimals, assembled before the giant impact phase of chaotic growth, potentially yield important implications for the final composition and evolution of terrestrial planets. These parameters critically depend on the internal balance of heating versus cooling, which is mostly determined by the presence of short-lived radionuclides (SLRs), such as aluminum-26 and iron-60, as well as the heat conductivity of the material. The heating by SLRs depends on their initial abundances, the formation time of the planetesimal and its size. It has been argued that the cooling history is determined by the porosity of the granular material, which undergoes dramatic changes via compaction processes and tends to decrease with time. In this study we assess the influence of these parameters on the thermo-mechanical evolution of young planetesimals with both 2D and 3D simulations. Using the code family I2ELVIS/I3ELVIS we have run numerous 2D and 3D numerical finite-dif...

  10. On the modelling of steel thermo-mechanical and metallurgical behaviour. Application to welding and heat treatment process

    The aim of this research is the prediction of residual stresses and strains in submarine nuclear reactor vessels after a welding operation. In the first part, the author briefly describes the various welding processes, their thermal, metallurgical and mechanical consequences, and gives an overview of the state-of-the-art of computerized modelling of welding. Then, he gives a detailed description of the various proposed models of the thermo-mechanical and metallurgical behaviours of steels. The influence of different phenomena such as plasticity, visco-plasticity, and transformation induced plasticity on the mechanical behaviour of the blend is analysed according to a sequential approach: the behaviour of each metallurgical phase is elastoplastic with linear kinetic cold working, then elasto-viscoplastic. A combined model is presented in which the ferrite phase behaviour is elastoplastic and the austenite behaviour is elasto-viscoplastic. The proposed models are then validated by two computer simulations performed with the COMSOL Multiphysics code. These simulations are simulating two tests which are representative of the phenomena met during a welding operation