Inappropriateness in composite laminate orthotropic elasticity formulations and numerical implementation of laminate elasto-plasticity within backward Euler integration algorithm

2018 ◽  
Vol 191 ◽  
pp. 119-122
Author(s):  
Rui Ren ◽  
ZhenDong Zhang ◽  
Jianlin Zhong ◽  
Dawei Ma
Keyword(s):  
Composite Laminate ◽  
Numerical Implementation ◽  
Integration Algorithm ◽  
Orthotropic Elasticity ◽  
Backward Euler ◽  
Elasto Plasticity

scholarly journals Numerical Implementation of a Hydro-Mechanical Coupling Constitutive Model for Unsaturated Soil Considering the Effect of Micro-Pore Structure

2021 ◽  
Vol 11 (12) ◽  
pp. 5368
Author(s):  
Guoqing Cai ◽  
Bowen Han ◽  
Mengzi Li ◽  
Kenan Di ◽  
Yi Liu ◽  
...  
Keyword(s):  
Constitutive Model ◽  
Mechanical Behavior ◽  
Pore Structure ◽  
Unsaturated Soil ◽  
Fortran Program ◽  
Numerical Implementation ◽  
Numerical Application ◽  
Integration Algorithm ◽  
Mechanical Coupling ◽  
Numerical Program

An unsaturated soil constitutive model considering the influence of microscopic pore structure can more accurately describe the hydraulic–mechanical behavior of unsaturated soil, but its numerical implementation is more complicated. Based on the fully implicit Euler backward integration algorithm, the ABAQUS software is used to develop the established hydro-mechanical coupling constitutive model for unsaturated soil, considering the influence of micro-pore structure, and a new User-defined Material Mechanical Behavior (UMAT) subroutine is established to realize the numerical application of the proposed model. The developed numerical program is used to simulate the drying/wetting cycle process of the standard triaxial specimen. The simulation results are basically consistent with those calculated by the Fortran program, which verifies the rationality of the developed numerical program.

FINITE ELEMENT IMPLEMENTATION OF A SUPER-ELASTIC CONSTITUTIVE MODEL FOR TRANSFORMATION RATCHETTING OF NiTi ALLOY

2012 ◽  
Vol 09 (01) ◽  
pp. 1240022 ◽  
Author(s):  
Q. H. KAN ◽  
G. Z. KANG ◽  
S. J. GUO
Keyword(s):  
Finite Element ◽  
Constitutive Model ◽  
Niti Alloy ◽  
Cyclic Stress ◽  
Euler Method ◽  
Convergence Criterion ◽  
Integration Algorithm ◽  
Finite Element Implementation ◽  
Backward Euler ◽  
Forward Transformation

In the previous work, a new constitutive model describing the transformation ratchetting of super-elastic NiTi alloy was proposed. The finite element implementation of the proposed model is discussed in this work, because such implementation is necessary to launch a numerical analysis for the cyclic stress–strain responses of NiTi alloy devices including the transformation ratchetting. During the implementation, a new stress integration algorithm is adopted, and a new expression of the consistent tangent modulus is derived for the forward transformation and the reverse transformation. The finite element implementation is elaborated by the user subroutine of UMAT in ABAQUS based on backward Euler method. The accumulated error during cyclic transformation is controlled by a robust convergence criterion. Finally, the validity of such implementation is verified by several numerical examples.

Research on WALKER Constitutive Model Tangent Modulus

2012 ◽  
Vol 249-250 ◽  
pp. 113-117
Author(s):  
Yan Chen ◽  
Qing Wu Wang ◽  
Quan Shan
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Constitutive Model ◽  
Constitutive Equations ◽  
Tangent Modulus ◽  
Finite Element Code ◽  
Numerical Examples ◽  
Rate Dependent ◽  
Backward Euler ◽  
Elasto Plasticity

In elasto-plasticity computation on materials by sub-increase finite element method, in general, it is necessary to calculate the consistent tangent modulus of elements. In this paper, based on the backward Euler integration, for an unified viscoplasticity constitutive equations, a new expression of consistent tangent modulus is derived for rate-dependent plasticity. The constitutive equations and consistent tangent modulus expression are implemented into a commercial finite element code-MARC. Numerical examples are given to verify the finite element implementation.This template explains and demonstrates how to prepare your camera-ready paper for Trans Tech Publications. The best is to read these instructions and follow the outline of this text.

scholarly journals A Coupled Elastoplastic Damage Model for Clayey Rock and Its Numerical Implementation and Validation

Geofluids ◽  
2020 ◽  
Vol 2020 ◽  
pp. 1-14 ◽  
Author(s):  
Shanpo Jia ◽  
Zhenyun Zhao ◽  
Guojun Wu ◽  
Bisheng Wu ◽  
Caoxuan Wen
Keyword(s):  
Damage Model ◽  
Clayey Rock ◽  
Triaxial Tests ◽  
Numerical Implementation ◽  
Integration Algorithm ◽  
Stress Criterion ◽  
Proposed Model ◽  
Maximal Tensile Stress ◽  
Nonlinear Hardening ◽  
Elastoplastic Damage

This paper presents a new constitutive model for describing the strain-hardening and strain-softening behaviors of clayey rock. As the conventional Mohr-Coulomb (CMC) criterion has its limitation in the tensile shear region, a modified Mohr-Coulomb (MMC) criterion is proposed for clayey rock by considering the maximal tensile stress criterion. Based on the results of triaxial tests, a coupled elastoplastic damage (EPD) model, in which the elastic and plastic damage laws are introduced to describe the nonlinear hardening and softening behaviors, respectively, is developed so as to fully describe the mechanical behavior of clayey rock. Starting from the implicit Euler integration algorithm, the stress-strain constitutive relationships and their numerical formulations are deduced for finite element implementation in the commercial package ABAQUS where a user-defined material subroutine (UMAT) is provided for clayey rock. Finally, the proposed model is used to simulate the triaxial tests and the results validate the proposed model and numerical implementation.

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