An Internal State Variable Elastoviscoplasticity-Damage Model for Irradiated Metals

2021 ◽  
Vol 144 (1) ◽  
Author(s):  
H. E. Cho ◽  
H. M. Zbib ◽  
M. F. Horstemeyer
Keyword(s):  
Internal State ◽  
Damage Model ◽  
Metal Alloys ◽  
Polycrystalline Materials ◽  
Internal State Variable ◽  
Structure Property ◽  
Irradiation Hardening ◽  
State Variable ◽  
Structure Property Relationships ◽  
Damage Constitutive Model

Abstract This study presents an irradiation-dependent internal state variable (ISV) elastoviscoplasticity-damage constitutive model that accounts for nuclear irradiation hardening and embrittlement of the irradiated polycrystalline materials. The irradiation effects were added to the coupled plasticity-damage kinetics with consideration of the structure–property relationships. The present irradiation-dependent elastoviscoplasticity-damage model was compared with the lab deformation experimental data of irradiated oxygen-free high conductivity (OFHC) copper, modified 9Cr-1Mo steel, and Ti-5Al-2.5Sn. The results show excellent agreement over the entire stress–strain curves at various irradiation doses. Because the ISV model, before the irradiation plasticity-damage addition, had been used on over 80 different metal alloys, it is anticipated that this nuclear irradiation supplement will also allow for application to many more irradiated metal alloys.

A Thermo-Electro-Elasto-Viscoplastic Damage Internal State Variable (ISV) Model for Ductile Metals

2018 ◽  
Author(s):  
Nikolay Dimitrov ◽  
Yucheng Liu ◽  
M. F. Horstemeyer
Keyword(s):  
Internal State ◽  
Deformation Gradient ◽  
Damage Model ◽  
Rate Equations ◽  
Thermodynamic Force ◽  
Practical Implementation ◽  
Internal State Variable ◽  
State Variable ◽  
Simplifying Assumptions ◽  
Future Work

A multiphysics Internal State Variable (ISV) theory that couples the thermoelastoviscoplastic damage model of Bammann-Horstemeyer with electricity-related electromagnetic phenomena is presented in which the kinematics, thermodynamics, and kinetics are internally consistent. An extended multiplicative decomposition of the deformation gradient that accounts for elasticity, plasticity, damage, thermal expansion, electricity, and magnetism is introduced. The different geometrically-affected rate equations are given for each phenomenon after the ISV formalism and have a thermodynamic force pair that acts as an internal stress-like quantity. Guidelines for practical implementation, recommendations for simplifying assumptions, and suggestions for future work supplement the theoretical model. The abstraction of the model can capture the full multi-physics described above; however, the robustness of the model is realized when any of the listed phenomena are not included in the boundary value problem, the model reduces to the previous form — the model will revert to the Bammann-Horstemeyer plasticity-damage ISV model.

Temperature-Dependent Fracture Mechanics-Informed Damage Model for Ceramic Matrix Composites

2021 ◽  
Author(s):  
Travis Skinner ◽  
Aditi Chattopadhyay
Keyword(s):  
Fracture Mechanics ◽  
Internal State ◽  
Damage Model ◽  
Ceramic Matrix ◽  
Model Parameters ◽  
Internal State Variable ◽  
Temperature Dependent ◽  
State Variable ◽  
Initiation And Propagation ◽  
Matrix Damage

Abstract This work presents a temperature-dependent reformulation of a multiscale fracture mechanics-informed matrix damage model previously developed by the authors. In this paper, internal state variable theory, fracture mechanics, and temperature-dependent material properties and model parameters are implemented to account for length scale-specific ceramic matrix composite (CMC) brittle matrix damage initiation and propagation behavior for temperatures ranging from room temperature (RT) to 1200°C. A unified damage internal state variable (ISV) is introduced to capture effects of matrix porosity, which occurs as a result of material diffusion around grain boundaries, as well as matrix property degradation due to matrix crack initiation and propagation. The porosity contribution to the unified damage ISV is related to the volumetric strain, and matrix cracking effects are captured using fracture mechanics and crack growth kinetics. A combination of temperature-dependent material properties and damage model parameters are included in the model to simulate effects of temperature on the deformation and damage behavior of 2D woven C/SiC CMC material systems. Model calibration is performed using experimental data from literature for plain weave C/SiC CMC at RT, 700°C, and 1200°C to determine how damage model parameters change in this temperature range. The nonlinear, temperature-dependent predictive capabilities of the reformulated model are demonstrated for 1000°C using interpolation to obtain expected damage model parameters at this temperature and the predictions are in good agreement with experimental results at 1000°C.

A Physically Motivated Internal State Variable Plasticity/Damage Model Embedded With a Length Scale for Hazmat Tank Cars’ Structural Integrity Applications

2011 ◽  
Author(s):  
Fazle R. Ahad ◽  
Koffi Enakoutsa ◽  
Kiran N. Solanki ◽  
Yustianto Tjipowidjojo ◽  
Douglas J. Bammann
Keyword(s):  
Evolution Equation ◽  
Internal State ◽  
Damage Model ◽  
Mesh Size ◽  
Material Behavior ◽  
Length Scale ◽  
Internal State Variable ◽  
State Variable ◽  
Fe Simulations ◽  
The Impact

In this study, we use a physically-motivated internal state variable plasticity/damage model containing a mathematical length scale to represent the material behavior in finite element (FE) simulations of a large scale boundary value problem. This problem consists of a moving striker colliding against a stationary hazmat tank car. The motivations are (1) to reproduce with high fidelity finite deformation and temperature histories, damage, and high rate phenomena which arise during the impact and (2) to address the pathological mesh size dependence of the FE solution in the post-bifurcation regime. We introduce the mathematical length scale in the model by adopting a nonlocal evolution equation for the damage, as suggested by Pijaudier-Cabot and Bazant (1987) in the context of concrete. We implement this evolution equation into existing implicit and explicit versions of the FE subroutines of the plasticity/failure model. The results of the FE simulations, carried out with the aid of Abaqus/Explicit FE code, show that the material model, accounting for temperature histories and nonlocal damage effects, satisfactorily predicts the damage progression during the tank car impact accident and significantly reduces the pathological mesh size effects.

An internal state variable damage model in crystal plasticity

2007 ◽  
Vol 39 (10) ◽  
pp. 941-952 ◽  
Author(s):  
G.P. Potirniche ◽  
M.F. Horstemeyer ◽  
X.W. Ling
Keyword(s):  
Crystal Plasticity ◽  
Internal State ◽  
Damage Model ◽  
Internal State Variable ◽  
State Variable

A Multiphase Internal State Variable Model With Rate Equations for Predicting Elastothermoviscoplasticity and Damage of Fiber Reinforced Polymer Composites

2017 ◽  
Author(s):  
Ge He ◽  
Yucheng Liu ◽  
D. J. Bammann ◽  
M. F. Horstemeyer
Keyword(s):  
Internal State ◽  
Damage Model ◽  
Matrix Cracking ◽  
Fiber Reinforced Polymer ◽  
Rate Equations ◽  
Internal State Variable ◽  
Fiber Reinforced ◽  
Variable Model ◽  
State Variable ◽  
Reinforced Polymer

This paper agglomerates an Internal State Variable (ISV) model for polymers (Bouvard et al., 2010, 2013) with damage evolution (Horstemeyer and Gokhale, 1999: Horstemeyer et al., 2000; Francis et al., 2014) into a multiphase ISV framework (Rajagopal and Tao, 1995; Bammann et al., 1996) that features a finite strain theoretical framework for Fiber Reinforced Polymer (FRP) composites under various stress states, temperatures, strain rates, and history dependencies. In addition to the inelastic ISVs for the polymer matrix and interphase, new ISVs associated with the interaction between phases are introduced. A scalar damage variable is employed to capture the damage history of such material, which is a result of three damage modes: matrix cracking, fiber breakage, and deterioration of the fiber-matrix interface, and each damage model was well calibrated to the experimental data from Rolland et al., (2016). The constitutive model developed herein arises employing standard postulates of continuum mechanics with the kinematics, thermodynamics, and kinetics being internally consistent.

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