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J Kadkhodapour - One of the best experts on this subject based on the ideXlab platform.
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micromechanics stress strain Behavior prediction of dual phase steel considering plasticity and grain boundaries debonding
Materials & Design, 2015Co-Authors: H Hosseinitoudeshky, B Anbarlooie, J KadkhodapourAbstract:Abstract Stress–strain response of multiphase materials similar to dual phase (DP) steel depends on the elastic–plastic and damage Behavior of all ingredient phases. DP steels typically contains of ferrite and martensite phases, but the grain boundaries of martensite phase may act as important location with possible occurrence of damage or debonding under static loading. The focus of this paper is consideration of ferrite and martensite interface debonding in addition to the elastic–plastic Behavior of ferrite and martensite to predict the stress–strain Behavior of DP steel using a finite element (FE) micromechanical approach. For this purpose the micromechanics representative geometry is selected from scanning electron microscopy (SEM) images and the finite element mesh is generated based on the real shape of grains. Interface elements based on the cohesive zone modeling are also used for consideration of damage or debonding on the ferrite and martensite interfaces. Therefore, the developed micro mechanic finite element model is based on the real microstructure, uses cohesive elements between martensite islands and ferrite matrix and also considers the elastic–plastic Behavior of ferrite and martensite phases. Handling of such simulation procedure with two source of material nonlinearity (plasticity and cohesive zone damage) is not an easy task. It is shown that the obtained stress–strain Behaviors are in well agreement with the experimental results.
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micromechanics stress strain Behavior prediction of dual phase steel considering plasticity and grain boundaries debonding
Materials & Design, 2015Co-Authors: H Hosseinitoudeshky, B Anbarlooie, J KadkhodapourAbstract:Abstract Stress–strain response of multiphase materials similar to dual phase (DP) steel depends on the elastic–plastic and damage Behavior of all ingredient phases. DP steels typically contains of ferrite and martensite phases, but the grain boundaries of martensite phase may act as important location with possible occurrence of damage or debonding under static loading. The focus of this paper is consideration of ferrite and martensite interface debonding in addition to the elastic–plastic Behavior of ferrite and martensite to predict the stress–strain Behavior of DP steel using a finite element (FE) micromechanical approach. For this purpose the micromechanics representative geometry is selected from scanning electron microscopy (SEM) images and the finite element mesh is generated based on the real shape of grains. Interface elements based on the cohesive zone modeling are also used for consideration of damage or debonding on the ferrite and martensite interfaces. Therefore, the developed micro mechanic finite element model is based on the real microstructure, uses cohesive elements between martensite islands and ferrite matrix and also considers the elastic–plastic Behavior of ferrite and martensite phases. Handling of such simulation procedure with two source of material nonlinearity (plasticity and cohesive zone damage) is not an easy task. It is shown that the obtained stress–strain Behaviors are in well agreement with the experimental results.
Mary C Boyce - One of the best experts on this subject based on the ideXlab platform.
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elastic plastic Behavior of non woven fibrous mats
Journal of The Mechanics and Physics of Solids, 2012Co-Authors: Meredith N Silberstein, Chialing Pai, Gregory C Rutledge, Mary C BoyceAbstract:Abstract Electrospinning is a novel method for creating non-woven polymer mats that have high surface area and high porosity. These attributes make them ideal candidates for multifunctional composites. Understanding the mechanical properties as a function of fiber properties and mat microstructure can aid in designing these composites. Further, a constitutive model which captures the membrane stress–strain Behavior as a function of fiber properties and the geometry of the fibrous network would be a powerful design tool. Here, mats electrospun from amorphous polyamide are used as a model system. The elastic–plastic Behavior of single fibers are obtained in tensile tests. Uniaxial monotonic and cyclic tensile tests are conducted on non-woven mats. The mat exhibits elastic–plastic stress–strain Behavior. The transverse strain Behavior provides important complementary data, showing a negligible initial Poisson's ratio followed by a transverse:axial strain ratio greater than −1:1 after an axial strain of 0.02. A triangulated framework has been developed to emulate the fibrous network structure of the mat. The micromechanically based model incorporates the elastic–plastic Behavior of single fibers into a macroscopic membrane model of the mat. This representative volume element based model is shown to capture the uniaxial elastic–plastic response of the mat under monotonic and cyclic loading. The initial modulus and yield stress of the mat are governed by the fiber properties, the network geometry, and the network density. The transverse strain Behavior is linked to discrete deformation mechanisms of the fibrous mat structure including fiber alignment, fiber bending, and network consolidation. The model is further validated in comparison to experiments under different constrained axial loading conditions and found to capture the constraint effect on stiffness, yield, post-yield hardening, and post-yield transverse strain Behavior. Due to the direct connection between microstructure and macroscopic Behavior, this model should be extendable to other electrospun systems and other two dimensional random fibrous networks.
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constitutive modeling of the rate temperature and hydration dependent deformation response of nafion to monotonic and cyclic loading
Journal of Power Sources, 2010Co-Authors: Meredith N Silberstein, Mary C BoyceAbstract:Abstract The elastic–plastic Behavior of the polymer electrolyte membrane (PEM) Nafion is characterized via monotonic and cyclic uniaxial tension testing as a function of strain rate, temperature, and hydration. Dynamic mechanical analysis shows that, under dry (30%RH) conditions, the material begins to transition from the glassy to the rubbery state at 75 ° C, with a glass transition of 105 ° C. DMA reveals the fully hydrated state to be significantly more compliant than the dry state, with a glass transition beginning at 40 ° C. Large strain monotonic tensile tests find the rate-dependent stress–strain Behavior to be highly dependent on temperature and hydration. The dry state transitions from an elastic–plastic Behavior at 25 ° C to an increasingly more compliant Behavior and lower yield stress as temperature is increased through the glass transition, until exhibiting a rubbery-like Behavior at 100 ° C. At 25 ° C, the stress–strain Behavior remains Elastic-Plastic for all hydrated states with the stiffness and yield stress decreasing with increasing hydration. Increasing hydration at all temperatures acts to decrease the initial elastic stiffness and yield stress. Unloading from different strains reveals the Elastic-Plastic nature of the Behavior even for the elevated temperature and hydrated states. Cyclic loading-unloading-reloading excursions to different strains show significant nonlinear recovery at all strains past yield with a highly nonlinear reloading Behavior which rejoins the initial loading path. A micromechanically motivated constitutive model consisting of an intermolecular resistance in parallel with an elastic network resistance is shown to be capable of capturing the rate, temperature, and hydration dependence of the monotonic stress-strain Behavior. The intermolecular resistance captures the local intermolecular barriers to initial elastic deformation and also captures the thermally activated nature of yield; these intermolecular barriers are modeled to decrease with increasing temperature and hydration, in particular mimicking the reduction in these barriers as the material approaches and enters the glass transition regime, successfully capturing the strong temperature and hydration dependence of the stress-strain Behavior. The highly nonlinear post-yield unloading and reloading suggest the development of a back stress during inelastic deformation which aids reverse plastic flow during unloading. Inclusion of a back stress which saturates after reaching a critical level provides an ability to capture the highly nonlinear cyclic loading stress response. Hence, the proposed model provides the capability to describe the complex evolution of stress and strain that occurs in PEM membranes due to the constrained hygrothermal cyclic swelling/deswelling characteristic of membranes in operating fuel cells.
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nanoscale anisotropic plastic deformation in single crystal aragonite
Physical Review Letters, 2006Co-Authors: Cathal J Kearney, Mary C Boyce, Z Zhao, B J F Bruet, Raul Radovitzky, Christine OrtizAbstract:The nanoscale anisotropic Elastic-Plastic Behavior of single-crystal aragonite is studied using nanoindentation and tapping mode atomic force microscopy imaging. Force-depth curves coaxial to the axis exhibited load plateaus indicative of dislocation nucleation events. Plasticity on distinct slip systems was evident in residual topographic impressions where four pileup lobes were present after indentation with a conospherical probe and distinct, protruding slip bands were present after indentation with a Berkovich pyramidal probe. A finite element crystal plasticity model revealed the governing roles of the {110} slip system family, as well as the (100)[010], (100)[001], (010)[100], (010)[001], (001)[100] and (001)[010] systems.
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a constitutive model for the anisotropic elastic plastic deformation of paper and paperboard
International Journal of Solids and Structures, 2002Co-Authors: Mary C Boyce, D M ParksAbstract:Abstract A three-dimensional, anisotropic constitutive model is presented to model the in-plane elastic–plastic deformation of paper and paperboard. The proposed initial yield surface is directly constructed from internal state variables comprising the yield strengths measured in various loading directions and the corresponding ratios of plastic strain components. An associated flow rule is used to model the plastic flow of the material. Anisotropic strain hardening of yield strengths is introduced to model the evolution in the yield surface with strain. A procedure for identifying the needed material properties is provided. The constitutive model is found to capture major features of the highly anisotropic elastic–plastic Behavior of paper and paperboard. Furthermore, with material properties fitted to experimental data in one set of loading directions, the model predicts the Behavior of other loading states well.
Zhen Zhang - One of the best experts on this subject based on the ideXlab platform.
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triaxial Behavior of granular material under complex loading path by a new numerical true triaxial engine
Advanced Powder Technology, 2019Co-Authors: Xiaoliang Wang, Zhen ZhangAbstract:Abstract A new numerical true triaxial engine based on discrete element method accounting for rolling resistance contact is developed. By this engine, we have simulated mechanical Behavior of granular materials under complex stress loading path in this study. Stress-strain responses of a kind of typical granular sand under several stress loading path in meridian and deviatoric stress space are provided. The results show that the three dimensional effects like the intermediate principal stress play an important role in the modeling processes. Theoretical analysis in strength characteristic implies the strength criteria with three parameters such as unified strength criterion and van Eekelen strength criterion are capable of describing cohesionless granular material Behaviors in three dimensional stress states. Moreover, the case study for Chende sand further demonstrates the numerical true triaxial engine, is a potential tool. As compared to conventional triaxial compression test, this new developed apparatus could be widely used to “measure” Elastic-Plastic Behavior in three dimensional stress space for finite element analysis in geotechnical problems.
H Hosseinitoudeshky - One of the best experts on this subject based on the ideXlab platform.
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micromechanics stress strain Behavior prediction of dual phase steel considering plasticity and grain boundaries debonding
Materials & Design, 2015Co-Authors: H Hosseinitoudeshky, B Anbarlooie, J KadkhodapourAbstract:Abstract Stress–strain response of multiphase materials similar to dual phase (DP) steel depends on the elastic–plastic and damage Behavior of all ingredient phases. DP steels typically contains of ferrite and martensite phases, but the grain boundaries of martensite phase may act as important location with possible occurrence of damage or debonding under static loading. The focus of this paper is consideration of ferrite and martensite interface debonding in addition to the elastic–plastic Behavior of ferrite and martensite to predict the stress–strain Behavior of DP steel using a finite element (FE) micromechanical approach. For this purpose the micromechanics representative geometry is selected from scanning electron microscopy (SEM) images and the finite element mesh is generated based on the real shape of grains. Interface elements based on the cohesive zone modeling are also used for consideration of damage or debonding on the ferrite and martensite interfaces. Therefore, the developed micro mechanic finite element model is based on the real microstructure, uses cohesive elements between martensite islands and ferrite matrix and also considers the elastic–plastic Behavior of ferrite and martensite phases. Handling of such simulation procedure with two source of material nonlinearity (plasticity and cohesive zone damage) is not an easy task. It is shown that the obtained stress–strain Behaviors are in well agreement with the experimental results.
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micromechanics stress strain Behavior prediction of dual phase steel considering plasticity and grain boundaries debonding
Materials & Design, 2015Co-Authors: H Hosseinitoudeshky, B Anbarlooie, J KadkhodapourAbstract:Abstract Stress–strain response of multiphase materials similar to dual phase (DP) steel depends on the elastic–plastic and damage Behavior of all ingredient phases. DP steels typically contains of ferrite and martensite phases, but the grain boundaries of martensite phase may act as important location with possible occurrence of damage or debonding under static loading. The focus of this paper is consideration of ferrite and martensite interface debonding in addition to the elastic–plastic Behavior of ferrite and martensite to predict the stress–strain Behavior of DP steel using a finite element (FE) micromechanical approach. For this purpose the micromechanics representative geometry is selected from scanning electron microscopy (SEM) images and the finite element mesh is generated based on the real shape of grains. Interface elements based on the cohesive zone modeling are also used for consideration of damage or debonding on the ferrite and martensite interfaces. Therefore, the developed micro mechanic finite element model is based on the real microstructure, uses cohesive elements between martensite islands and ferrite matrix and also considers the elastic–plastic Behavior of ferrite and martensite phases. Handling of such simulation procedure with two source of material nonlinearity (plasticity and cohesive zone damage) is not an easy task. It is shown that the obtained stress–strain Behaviors are in well agreement with the experimental results.
D M Parks - One of the best experts on this subject based on the ideXlab platform.
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a constitutive model for the anisotropic elastic plastic deformation of paper and paperboard
International Journal of Solids and Structures, 2002Co-Authors: Mary C Boyce, D M ParksAbstract:Abstract A three-dimensional, anisotropic constitutive model is presented to model the in-plane elastic–plastic deformation of paper and paperboard. The proposed initial yield surface is directly constructed from internal state variables comprising the yield strengths measured in various loading directions and the corresponding ratios of plastic strain components. An associated flow rule is used to model the plastic flow of the material. Anisotropic strain hardening of yield strengths is introduced to model the evolution in the yield surface with strain. A procedure for identifying the needed material properties is provided. The constitutive model is found to capture major features of the highly anisotropic elastic–plastic Behavior of paper and paperboard. Furthermore, with material properties fitted to experimental data in one set of loading directions, the model predicts the Behavior of other loading states well.
