Non-coaxial elasto-plasticity model and bifurcation prediction of shear banding in sands

2009 ◽  
pp. n/a-n/a
Author(s):  
Maosong Huang ◽  
Xilin Lu ◽  
Jiangu Qian
Keyword(s):  
Shear Banding ◽  
Plasticity Model ◽  
Elasto Plasticity

Application of generalized measures to an orthotropic finite elasto-plasticity model

2003 ◽  
Vol 28 (3-4) ◽  
pp. 696-703 ◽  
Author(s):  
J Löblein ◽  
J Schröder ◽  
F Gruttmann
Keyword(s):  
Plasticity Model ◽  
Elasto Plasticity

Bifurcation Analyses of Steel and Concrete with Rate-Dependent Properties Part One: Model Formulation and Verification

2002 ◽  
Vol 4 (4) ◽  
pp. 217-224
Author(s):  
Yuxing Liu ◽  
Luming Shen ◽  
Zhen Chen
Keyword(s):  
Damage Model ◽  
Three Dimensional ◽  
Plain Concrete ◽  
Environmental Engineering ◽  
Material Failure ◽  
Plasticity Model ◽  
Model Formulation ◽  
University Of Missouri ◽  
Rate Dependent ◽  
Elasto Plasticity

Department of Civil and Environmental Engineering, University of Missouri-Columbia, Columbia MO 65211–2200, U.S.A. The effects of strain rate on the mechanical properties of carbon steel and plain concrete are investigated through a rate-dependent elasto-plasticity model and rate-dependent elasto-damage model, respectively. Continuum tangent stiffness tensors are derived for both models so that bifurcation analyses can be performed to identify the onset of material failure. Three-dimensional constitutive model solvers are designed and the numerical results are compared with the experimental data to verify the proposed models.

Shear Band Analysis for Lubricants Based on a Viscoelastic Plasticity Model

1994 ◽  
Vol 47 (6S) ◽  
pp. S209-S220 ◽  
Author(s):  
Y. K. Lee ◽  
J. Ghosh ◽  
S. Bair ◽  
W. O. Winer
Keyword(s):  
Coupling Effect ◽  
Fluid Model ◽  
Shear Banding ◽  
Shear Bands ◽  
Sufficient Conditions ◽  
Maxwell Fluid ◽  
Plasticity Model ◽  
Field Equations ◽  
Necessary And Sufficient ◽  
Independent Behavior

Shear banding is an outstanding problem in lubricant rheology where a thin film of lubricant is under high pressure and high shear stress. To study such a phenomenon, a viscoelastic-plastic model is proposed. It is postulated that shear bands appear when the character of the field equations changes from elliptic to hyperbolic. The model is derived based on a rate formulation which combines a Maxwell fluid model and a compressible rate-independent plasticity model. The model gives the constitutive relation of a compressible viscoelastic-plastic fluid for which the assumption of Stokes condition becomes unnecessary. It also accounts for the elastic coupling effect of both the viscous and the rate-independent behavior of a lubricant. It provides a novel feature that the development of shear bands can be tracked rather than being determined after they are fully developed. Hence, the process of shear banding may be articulated. The analysis focuses on identifying necessary and sufficient conditions which, if achieved in a deformation, would produce a change in character of the governing field equations. Through the use of Drucker-Prager criterion as the component that governs the rate-independent behavior of a lubricant, the analysis gives results that are in accord with experimental observations. Parametric results are given graphically.

Thermodynamically Consistent Anisotropic Plasticity Model

2006 ◽  
Author(s):  
Alexander A. Lukyanov
Keyword(s):  
Stress Tensor ◽  
Material Properties ◽  
Main Role ◽  
Plasticity Model ◽  
Anisotropic Plasticity ◽  
Future Studies ◽  
Hill Criterion ◽  
Kronecker Delta ◽  
Elasto Plasticity ◽  
Deviatoric Part

The objective of the work presented in this paper is to consider the thermodynamically consistent anisotropic plasticity model based on full decomposition of stress tensor into generalised deviatoric part and generalised spherical part of stress tensor. Two fundamental tensors αij and βij which represents anisotropic material properties are defined and can be considered as generalisations of the Kronecker delta symbol which plays the main role in the theory of isotropic materials. Using two fundamental tensors, αij and βij, the concept of total generalised “pressure” and pressure corresponding to the volumetric deformation are redefined. It is shown that the formulation of anisotropic plasticity in the case of incompressible plastic flow must be considered independently from the generalised hydrostatic “pressure”. Accordingly, a modification to the anisotropic Hill criterion is introduced. Based on experimental research which has been published, the modified Hill (1948, 1950) criterion for anisotropic elasto-plasticity is validated. The results are presented, discussed and future studies are outlined.

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