Microscopically based new damage constitutive model with applications

Abstract

In this paper we put forward a new formulation of constitutive relations based on micro-mechanical analysis to describe the behavior of damaged materials. The constitutive theory of continuum damage mechanics has been further developed, based on the foundations of elastoplastic deformation and analysis of the mechanical behavior of a microelement of damaged material in which different damage mechanisms are involved. The description of ductile fracture phenomena by the evolution of damage parameter f, measuring the void volume fraction, is applied. Softening functions have been introduced into the macroscopic constitutive equations to model the damage effects on material response. The method has been applied to the analysis of the stress and damage distribution near the tip of the notch of the notched bar under uniaxial loading. Calculated results for distribution of stress and damage, based on the new constitutive description and corresponding finite element code, are compared with the experimental data obtained by deformation tests and photointerpreter. Calculated results show satisfactory agreement with experimental data.