A THEORY OF DAMAGE IN BRITTLE MATERIALS

The present paper addresses the geometric representation of damage in brittle solids, its equation of evolution and its incorporation in the constitutive equation. The concept of a damage coordinate is introduced and a thermodynamic derivation of the evolution equation follows. A continuum damage theory ensues. The theory is applied to the case of a thin plate with a central crack under a tensile load in a direction normal to the plane of the crack. The fracture stress is calculated numerically using a finite element code for various crack lengths and a comparison is made with its observed value. Excellent agreement between the two is obtained with the aid of only one damage parameter, the damage propensity constant. A congruence between the theory and linear fracture mechanics is then shown when the damage coordinate is the crack length. © 1990.