Multiple surface crack initiation and growth in glass-ceramics loaded by a sphere

A study is presented in which a finite element method was used to visualize initiation and growth of a crack system observed in Hertzian contact between a sphere and a glass-ceramic half-space with limited plasticity. This method uses a micromechanically based approach to simulate crack evolution, and a unified stress-based fracture criterion to predict the crack initiation and growth. Stress intensity factors (SIFs) at the crack tip are first computed. The effect of plasticity on the SIFs is investigated. A fracture parameter is proposed as a function of material toughness and mesh scale. Visualizations of the crack system that were performed to verify the proposed unified stress-based fracture criterion are reported. (C) 2000 Elsevier Science Ltd. All rights reserved.