3D modeling of cleavage crack arrest with a stress criterion

Abstract

Thermal shock experiments on precracked discs were carried out in order to study cleavage crack arrest capabilities of one bainitic steel. Two thicknesses of specimen were used. Standard analysis shows no influence of thickness but an influence of the initial crack length on arrest toughness. A local stress criterion based on the maximal principal stress was applied in order to predict brittle crack arrest. 3D finite element models were developed in order to simulate the shape of the crack front. A scatter in critical stress for cleavage crack arrest was introduced through Monte-Carlo simulations and Weibull distribution. The comparison with the experiment is accurate, that shows a good potential of the stress criterion for predicting cleavage crack arrest. The scatter of critical stress influences the regularity of the simulated crack arrest front, but not the crack length. The cleavage crack propagation and arrest could then be simulated by the mean value of the local fracture stress.