The Experts below are selected from a list of 19908 Experts worldwide ranked by ideXlab platform
Sebastian Munstermann - One of the best experts on this subject based on the ideXlab platform.
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a strain gradient isotropic elastoplastic damage model with j3 dependence
International Journal of Solids and Structures, 2019Co-Authors: Ioanna Papadioti, N Aravas, Junhe Lian, Sebastian MunstermannAbstract:Abstract A “plastic-strain-gradient” version of an isotropic elastoplastic damage model that depends on the third invariant J3 of the stress deviator is developed. The model is based on the “non-local” equivalent plastic strain ep defined by Peerlings et al. (2001) and Engelen et al. (2003) and introduces a “material length” l to the constitutive equations. It is shown that the non-local equivalent plastic strain ep at a material point P can be identified with the average value of the local von Mises equivalent plastic strain e ¯ p over a sphere centered at P and of radius approximately equal to 3 l. A methodology for the numerical integration of the constitutive equations is presented. The algorithm is appropriate for rate-independent as well as rate-dependent (viscoplastic) models. The model is implemented in the ABAQUS general-purpose finite element program and both quasi-static and dynamic problems are solved. Two possible ABAQUS implementations are discussed. First,“user elements” are developed, which can be used for the solution of both quasi-static and dynamic problems. Reduced 1-point Gauss integration is discussed in 8-node hexahedral elements and the “physical stabilization” method of Puso (2000) is used to remove the resulting numerical singularities (hourglass control). Second, the implementation of the model via “user material” Subroutines is discussed. Quasi-static problems can be solved with ABAQUS/Standard using a *COUPLED TEMPERATURE-DISPLACEMENT, STEADY STATE analysis together with user Subroutine UMAT, in which temperature is identified with the non-local equivalent plastic strain ep; the solution of dynamic problems requires use of ABAQUS/Explicit together with a *DYNAMIC TEMPERATURE-DISPLACEMENT analysis option and user Subroutines VUMAT and DFLUX. Several example problems are solved.
Junhe Lian - One of the best experts on this subject based on the ideXlab platform.
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a strain gradient isotropic elastoplastic damage model with j3 dependence
International Journal of Solids and Structures, 2019Co-Authors: Ioanna Papadioti, N Aravas, Junhe Lian, Sebastian MunstermannAbstract:Abstract A “plastic-strain-gradient” version of an isotropic elastoplastic damage model that depends on the third invariant J3 of the stress deviator is developed. The model is based on the “non-local” equivalent plastic strain ep defined by Peerlings et al. (2001) and Engelen et al. (2003) and introduces a “material length” l to the constitutive equations. It is shown that the non-local equivalent plastic strain ep at a material point P can be identified with the average value of the local von Mises equivalent plastic strain e ¯ p over a sphere centered at P and of radius approximately equal to 3 l. A methodology for the numerical integration of the constitutive equations is presented. The algorithm is appropriate for rate-independent as well as rate-dependent (viscoplastic) models. The model is implemented in the ABAQUS general-purpose finite element program and both quasi-static and dynamic problems are solved. Two possible ABAQUS implementations are discussed. First,“user elements” are developed, which can be used for the solution of both quasi-static and dynamic problems. Reduced 1-point Gauss integration is discussed in 8-node hexahedral elements and the “physical stabilization” method of Puso (2000) is used to remove the resulting numerical singularities (hourglass control). Second, the implementation of the model via “user material” Subroutines is discussed. Quasi-static problems can be solved with ABAQUS/Standard using a *COUPLED TEMPERATURE-DISPLACEMENT, STEADY STATE analysis together with user Subroutine UMAT, in which temperature is identified with the non-local equivalent plastic strain ep; the solution of dynamic problems requires use of ABAQUS/Explicit together with a *DYNAMIC TEMPERATURE-DISPLACEMENT analysis option and user Subroutines VUMAT and DFLUX. Several example problems are solved.
N Aravas - One of the best experts on this subject based on the ideXlab platform.
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a strain gradient isotropic elastoplastic damage model with j3 dependence
International Journal of Solids and Structures, 2019Co-Authors: Ioanna Papadioti, N Aravas, Junhe Lian, Sebastian MunstermannAbstract:Abstract A “plastic-strain-gradient” version of an isotropic elastoplastic damage model that depends on the third invariant J3 of the stress deviator is developed. The model is based on the “non-local” equivalent plastic strain ep defined by Peerlings et al. (2001) and Engelen et al. (2003) and introduces a “material length” l to the constitutive equations. It is shown that the non-local equivalent plastic strain ep at a material point P can be identified with the average value of the local von Mises equivalent plastic strain e ¯ p over a sphere centered at P and of radius approximately equal to 3 l. A methodology for the numerical integration of the constitutive equations is presented. The algorithm is appropriate for rate-independent as well as rate-dependent (viscoplastic) models. The model is implemented in the ABAQUS general-purpose finite element program and both quasi-static and dynamic problems are solved. Two possible ABAQUS implementations are discussed. First,“user elements” are developed, which can be used for the solution of both quasi-static and dynamic problems. Reduced 1-point Gauss integration is discussed in 8-node hexahedral elements and the “physical stabilization” method of Puso (2000) is used to remove the resulting numerical singularities (hourglass control). Second, the implementation of the model via “user material” Subroutines is discussed. Quasi-static problems can be solved with ABAQUS/Standard using a *COUPLED TEMPERATURE-DISPLACEMENT, STEADY STATE analysis together with user Subroutine UMAT, in which temperature is identified with the non-local equivalent plastic strain ep; the solution of dynamic problems requires use of ABAQUS/Explicit together with a *DYNAMIC TEMPERATURE-DISPLACEMENT analysis option and user Subroutines VUMAT and DFLUX. Several example problems are solved.
Ioanna Papadioti - One of the best experts on this subject based on the ideXlab platform.
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a strain gradient isotropic elastoplastic damage model with j3 dependence
International Journal of Solids and Structures, 2019Co-Authors: Ioanna Papadioti, N Aravas, Junhe Lian, Sebastian MunstermannAbstract:Abstract A “plastic-strain-gradient” version of an isotropic elastoplastic damage model that depends on the third invariant J3 of the stress deviator is developed. The model is based on the “non-local” equivalent plastic strain ep defined by Peerlings et al. (2001) and Engelen et al. (2003) and introduces a “material length” l to the constitutive equations. It is shown that the non-local equivalent plastic strain ep at a material point P can be identified with the average value of the local von Mises equivalent plastic strain e ¯ p over a sphere centered at P and of radius approximately equal to 3 l. A methodology for the numerical integration of the constitutive equations is presented. The algorithm is appropriate for rate-independent as well as rate-dependent (viscoplastic) models. The model is implemented in the ABAQUS general-purpose finite element program and both quasi-static and dynamic problems are solved. Two possible ABAQUS implementations are discussed. First,“user elements” are developed, which can be used for the solution of both quasi-static and dynamic problems. Reduced 1-point Gauss integration is discussed in 8-node hexahedral elements and the “physical stabilization” method of Puso (2000) is used to remove the resulting numerical singularities (hourglass control). Second, the implementation of the model via “user material” Subroutines is discussed. Quasi-static problems can be solved with ABAQUS/Standard using a *COUPLED TEMPERATURE-DISPLACEMENT, STEADY STATE analysis together with user Subroutine UMAT, in which temperature is identified with the non-local equivalent plastic strain ep; the solution of dynamic problems requires use of ABAQUS/Explicit together with a *DYNAMIC TEMPERATURE-DISPLACEMENT analysis option and user Subroutines VUMAT and DFLUX. Several example problems are solved.
James A. Miller - One of the best experts on this subject based on the ideXlab platform.
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Supercedes SAND86-8246B A FORTRAN COMPUTER CODE PACKAGE FOR THE EVALUATION OF GAS-PHASE, MULTICOMPONENT TRANSPORT PROPERTIES
1998Co-Authors: Robert J. Kee, James A. Miller, Michael E. Coltrin, Graham Dixon-lewis, Jürgen Warnatz, Harry K. MoffatAbstract:This report documents a FORTRAN computer code package that is used for the evaluation of gas-phase multicomponent viscosities, thermal conductivities, diffusion coefficients, and thermal diffusion coefficients. The TRANSPORT Property package is in two parts. The first is a preprocessor that computes polynomial fits to the temperature dependent parts of the pure species viscosities and binary diffusion coefficients. The coefficients of these fits are passed to a library of Subroutines via a linking file. Then, any Subroutine from this library may be called to return either pure species properties or multicomponent gas mixture properties. This package uses the gas-phase chemical kinetics package CHEMKIN-III, and the TRANSPORT property Subroutines are designed to be used in conjunction with the CHEMKIN-III Subroutine library
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chemkin iii a fortran chemical kinetics package for the analysis of gas phase chemical and plasma kinetics
Other Information: PBD: May 1996, 1996Co-Authors: F. M. Rupley, Ellen Meeks, James A. MillerAbstract:This document is the user`s manual for the third-generation CHEMKIN package. CHEMKIN is a software package whose purpose is to facilitate the formation, solution, and interpretation of problems involving elementary gas-phase chemical kinetics. It provides a flexible and powerful tool for incorporating complex chemical kinetics into simulations of fluid dynamics. The package consists of two major software components: an Interpreter and a Gas-Phase Subroutine Library. The Interpreter is a program that reads a symbolic description of an elementary, user-specified chemical reaction mechanism. One output from the Interpreter is a data file that forms a link to the Gas-Phase Subroutine Library. This library is a collection of about 100 highly modular FORTRAN Subroutines that may be called to return information on equations of state, thermodynamic properties, and chemical production rates. CHEMKIN-III includes capabilities for treating multi-fluid plasma systems, that are not in thermal equilibrium. These new capabilities allow researchers to describe chemistry systems that are characterized by more than one temperature, in which reactions may depend on temperatures associated with different species; i.e. reactions may be driven by collisions with electrons, ions, or charge-neutral species. These new features have been implemented in such a way as to require little or no changes to CHEMKIN implementation for systems in thermal equilibrium, where all species share the same gas temperature. CHEMKIN-III now has the capability to handle weakly ionized plasma chemistry, especially for application related to advanced semiconductor processing.
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CHEMKIN-III: A Fortran Chemical Kinetics Package for the Analysis of Gas Phase Chemical and Plasma Kinetics," Sandia National Laboratories Report
1996Co-Authors: Robert J. Kee, F. M. Rupley, Ellen Meeks, James A. MillerAbstract:This document is the user's manual for the third-generation CHEMKIN package. CHEMKIN is a software package whose purpose is to facilitate the formation, solution, and interpretation of problems involving elementary gas-phase chemical kinetics. It provides a flexible and powerful tool for incorporating complex chemical kinetics into simulations of fluid dynamics. The package consists of two major software components: an Interpreter and a Gas-Phase Subroutine Library. The Interpreter is a program that reads a symbolic description of an elementary, user-specified chemical reaction mechanism. One output from the Interpreter is a data file that forms a link to the Gas-Phase Subroutine Library. This library is a collection of about 100 highly modular FORTRAN Subroutines that may be called to return information on equations of state, thermodynamic properties, and chemical production rates. CHEMKIN-III includes capabilities for treating multi-fluid plasma systems, that are not in thermal equilibrium. These new capabilities allow researchers to describe chemistry systems that are characterized by more than one temperature, in which reactions may depend on temperatures associated with different species; i.e. reactions may be driven by collisions with electrons, ions, or charge-neutral species. These new features have been implemented in such a way as to require little o
