Fracture mechanics interpretation of multiple-creep cracking using damage-mechanics concepts

Abstract

Damage-mechanics concepts are incorporated into a fracture-mechanics interpretation of multiple grain-boundary cracking in uniaxial tensile creep specimens that undergo power–law creep deformation. Initially, methods of evaluating the fracture–mechanics creep parameter C^* for a structure containing a single macroscopic crack are extended to a uniform distribution of grain-boundary voids. Damage-mechanics models are then applied to describe damage accumulation. It is shown that, when the voids grow as disc-shaped cavities, the analysis yields predictions of growth rates which are consistent with characterizations of macroscopic crack growth behaviour involving the exhaustion of the available creep ductility in a process zone at the crack tip.

MST/195