scholarly journals A Two-Surface Model with Anisotropic Hardening and Nonassociated Flow Rule for Geomaterials

1998 ◽  
Vol 38 (1) ◽  
pp. 45-59 ◽  
Author(s):  
Shoichi Kiyama ◽  
Takashi Hasegawa
Keyword(s):  
Surface Model ◽  
Flow Rule ◽  
Anisotropic Hardening ◽  
Nonassociated Flow Rule

A non-quadratic pressure-sensitive constitutive model under non-associated flow rule with anisotropic hardening: Modeling and validation

2020 ◽  
Vol 135 ◽  
pp. 102808 ◽  
Author(s):  
Yong Hou ◽  
Junying Min ◽  
Thomas B. Stoughton ◽  
Jianping Lin ◽  
John E. Carsley ◽  
...  
Keyword(s):  
Constitutive Model ◽  
Flow Rule ◽  
Anisotropic Hardening ◽  
Pressure Sensitive ◽  
Associated Flow Rule

A Generalized Anisotropic Hardening Rule Based on the Mroz Multi-Yield-Surface Model

2008 ◽  
Author(s):  
K. S. Choi ◽  
J. Pan
Keyword(s):  
Cyclic Loading ◽  
Yield Surface ◽  
Kinematic Hardening ◽  
Constitutive Relations ◽  
Yield Function ◽  
Surface Model ◽  
Loading Conditions ◽  
Anisotropic Hardening ◽  
Hardening Rule ◽  
Strain Data

In this paper, a generalized anisotropic hardening rule based on the Mroz multi-yield-surface model is derived. The evolution equation for the active yield surface is obtained by considering the continuous expansion of the active yield surface during the unloading/reloading process. The incremental constitutive relation based on the associated flow rule is then derived for a general yield function. As a special case, detailed incremental constitutive relations are derived for the Mises yield function. The closed-form solutions for one-dimensional stress-plastic strain curves are also derived and plotted for the Mises materials under cyclic loading conditions. The stress-plastic strain curves show closed hysteresis loops under uniaxial cyclic loading conditions and the Masing hypothesis is applicable. A user material subroutine based on the Mises yield function, the anisotropic hardening rule and the constitutive relations was then written and implemented into ABAQUS. Computations were conducted for a simple plane strain finite element model under uniaxial monotonic and cyclic loading conditions based on the anisotropic hardening rule and the isotropic and nonlinear kinematic hardening rules of ABAQUS. The results indicate that the plastic response of the material follows the intended input stress-strain data for the anisotropic hardening rule whereas the plastic response depends upon the input strain ranges of the stress-strain data for the nonlinear kinematic hardening rule.

An Associative and Non-Associative Anisotropic Bounding Surface Model for Clay

2012 ◽  
Vol 79 (3) ◽  
Author(s):  
Jianhong Jiang ◽  
Hoe I. Ling ◽  
Victor N. Kaliakin
Keyword(s):  
Mechanical Behavior ◽  
Strain Hardening ◽  
Strain Softening ◽  
Surface Model ◽  
Flow Rule ◽  
Reasonable Accuracy ◽  
Bounding Surface ◽  
Softening Behavior ◽  
Different Types ◽  
Undrained Behavior

An anisotropic elastoplastic bounding surface model with non-associative flow rule is developed for simulating the mechanical behavior of different types of clays. The non-associative flow rule allows for the simulation of not only strain-hardening but also strain-softening response. The theoretical framework of the model is given, followed by the verification of the model as applied to the experimental results of a strain-hardening Kaolin tested under different undrained stress paths. The undrained behavior of Boston Blue clay, which exhibits a strain-softening behavior, is also simulated. It is shown that the non-associative nature of the model gives more accurate results than those of the same model employing an associative flow rule, especially for normally consolidated Kaolin specimens. The results show that the model is also capable of simulating the strain-softening behavior of Boston blue clay with reasonable accuracy.

Stability analysis of a deep buried elliptical tunnel in cohesive–frictional (c–ϕ) soils with a nonassociated flow rule

2017 ◽  
Vol 54 (5) ◽  
pp. 736-741 ◽  
Author(s):  
Feng Yang ◽  
Xinlei Sun ◽  
Xiangcou Zheng ◽  
Junsheng Yang
Keyword(s):  
Finite Element Method ◽  
Upper Bound ◽  
Yield Criterion ◽  
Ground Surface ◽  
Unit Weight ◽  
Flow Rule ◽  
Collapse Mechanisms ◽  
Nonassociated Flow Rule ◽  
Critical Unit ◽  
Soil Weight

The stabilities and associated collapse mechanisms of deep buried unlined elliptical tunnels in cohesive–frictional (c–[Formula: see text]) soils with the action of soil weight are investigated by the “upper-bound finite element method with rigid translatory moving elements” (UBFEM–RTME). The soil masses are assumed to obey the Mohr–Coulomb yield criterion and a nonassociated flow rule. Upper-bound stability coefficients (γcrD/c, where γcr is critical unit weight; D is tunnel height; c is cohesion) are deduced for different values of friction angles ([Formula: see text]), dilatancy coefficients (ψ/[Formula: see text], where ψ is dilation angle), and dimensionless spans (B/D, where B is span). The obtained collapse mechanisms do not extend to the ground surface and are primarily composed of a series of mutually movable rigid blocks. The γcrD/c values increase while the collapse zones decrease with an increasing [Formula: see text] and ψ/[Formula: see text] and a decreasing B/D.

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