Evolution of the stiffness tetrad in fiber-reinforced materials under large plastic strain : material plasticity

Abstract

The main aim of this work is to track the evolution of the stiffness tetrad during large plastic strain. Therefore, the framework of a general finite plasticity theory is developed. Some special cases are examined, and the case of a material plasticity theory is considered more closely. Its main feature is that the elasticity law changes during plastic deformations, for whichwe develop an approach.As samplematerials,we use three types of fiber-reinforced composites. For numerical experiments and verification of the model’s predictions, finite element simulations of representative volume elements for uni-, bi- and tri-directional reinforced materials with periodic boundary conditions are used. From these, we extract the stiffness tetrads before and after large deformations of the material.We quantify the change of the stiffness tetrads due to the fiber reorientation. Finally,we propose an analytical evolutionwith three parameters that account reasonablywell for the evolution of the stiffness tetrad.