Thermoplasticity and strain localization in transversely isotropic materials based on anisotropic critical state plasticity

• Published in: International journal for numerical and analytical methods in geomechanics 2016-12, Vol.40 (18), p.2423-2449
• Main Authors: Semnani, Shabnam J., White, Joshua A., Borja, Ronaldo I.
• Format: Article
• Language: English
• Subjects: Adiabatic flow; Anisotropy; bifurcatio; bifurcation; Computer simulation; Localization; MATERIALS SCIENCE; Mathematical models; Position (location); shear band; Slip bands; Strain localization; thermo-plasticity; thermoplasticity; transverse isotropy
• ISSN: 0363-9061; 1096-9853
• DOI: 10.1002/nag.2536

Summary Geomaterials such as soils and rocks are inherently anisotropic and sensitive to temperature changes caused by various internal and external processes. They are also susceptible to strain localization in the form of shear bands when subjected to critical loads. We present a thermoplastic framework for modeling coupled thermomechanical response and for predicting the inception of a shear band in a transversely isotropic material using the general framework of critical state plasticity and the specific framework of an anisotropic modified Cam–Clay model. The formulation incorporates anisotropy in both elastic and plastic responses under the assumption of infinitesimal deformation. The model is first calibrated using experimental data from triaxial tests to demonstrate its capability in capturing anisotropy in the mechanical response. Subsequently, stress‐point simulations of strain localization are carried out under two different conditions, namely, isothermal localization and adiabatic localization. The adiabatic formulation investigates the effect of temperature on localization via thermomechanical coupling. Numerical simulations are presented to demonstrate the important role of anisotropy, hardening, and thermal softening on strain localization inception and orientation. Copyright © 2016 John Wiley & Sons, Ltd.