We propose a decomposition of constitutive relations into crack-driving and persistent portions, specifically designed for materials with anisotropic/orthotropic behavior in the phase field approach to fracture account tension-compression asymmetry. This follows variational framework, satisfying orthogonality condition anisotropic materials. implies that present model can be applied arbitrary e...

biomechanical properties of soft tissue, such as liver, are important in modeling computer aided surgical procedures. experimental evidences show that liver tissue is transversely isotropic. in this article, considering the liver tissue as an incompressible fiber-reinforced composite with one family of fibers, an exponential strain energy function (sef) is proposed. the proposed sef is based on...

In their original formulation of the method of isotropic extension via structural tensors, which is meant for applications to the derivation of coordinate-free representation formulas for anisotropic constitutive functions, both Boehler and Liu start with the assumption that the invariance group of structural tensors is the symmetry group that defines the anisotropy of the constitutive function...

this paper presents a model for prediction of the mechanical behavior of sand-gravel mixtures using generalized plasticity and critical state concepts. proposed model is based on the difference between critical state lines of sand and sand-gravel mixture in e-lnp' plane. a generalized plasticity model is considered as the base model for sandy soil. its state parameter, dilation rate and ha...

In this paper, the general case of an anisotropic thermo-electro elastic body subjected to static biasing fields is considered. The biasing fields may be introduced by heat flux, body forces, external surface tractions, and electric fields. By introducing proper thermodynamic functions and employing variational principle for a thermo-electro elastic body, the nonlinear constitutive relations an...

Dense granular materials behave differently from classical fluids or solids and can not be described through the continuum theories developed for those. In fact behavior at macro-scale is strongly related to smaller-scale field variables and kinetic processes. The influence of the micromechanics on the non-coaxiality of stress, strain and anisotropy of soils, is an essential part of a constitut...