Analysis of stable crack growth in brittle materials Part II: A bridge zone model

Abstract

The phenomenon of stable crack growth in brittle materials is considered where stable crack growth is modeled as the formation of a bridge zone in the wake of a stably propagating main crack. The hypothesis that compressive zones surround and protect isolated ligaments under residual tension, which then leads to stable crack growth with attendant toughness enhancement, is incorporated into the bridge-zone formulation. Effects associated with debonding of ligaments on stable crack growth are explored via a simple treatment of microcrack branching. Similarity between the present bridge-zone description and a previously developed process-zone description of stable crack growth is quantitatively established. The importance of interpreting experimentally determined resistance-curve data subject to K-dominance requirements is highlighted by comparison of model predictions with select data in the literature.