DAMAGE MODEL FOR BRITTLE ELASTIC SOLIDS WITH UNEQUAL TENSILE AND COMPRESSIVE STRENGTHS

The paper presents a rate-type constitutive analysis of damage, applic able to brittle materials whose elastic properties degrade during a de formation process. Different tensile and compressive material response s are modeled incorporating positive and negative projections of the s tress or strain tensors. Proposed evolution laws for the rate of compl iance tensors are consistent with some of the prominent features of br ittle material response. A new structure of the damage surface is intr oduced for a more accurate account of the effects of the hydrostatic s tates of stress on the overall response. Derived rate constitutive equ ations provide the explicit representation of the tangent compliance t enser. The proposed model is applied to uniaxial tension and compressi on to illustrate nonlinear relationships between stress and longitudin al, lateral, and volumetric strains. The proposed model is compared wi th some of the existing theories.