Development of a dynamic model for crack propagation in glazing system under thermal loading

Abstract

The present study reports on the development and validation of a finite element program, GLAZ-CRACK, for predicting crack initiation and propagation of glass in fire or under other thermal loadings. The model is based on three crack modes to calculate the stress intensity factors (SIFs) and strain energy release rates. The crack initiation is predicted from the stress distribution using either probabilistic or deterministic method. The crack growth can be predicted by one of the three criterions, which are SIFs based mixed-mode criterion, energy release rates based mixed-mode criterion and SIFs based maximum circumferential stress criterion. The crack spread rate and crack direction are calculated based on first principles of fracture mechanics. A moving crack tip mesh topology is proposed to locally refine the grid resolution in the tip region. Predictions for the SIFs of a central horizontal crack in a square plate, a central horizontal crack in a long plate and a single edge cracked plate under plane stress condition show good agreement with either the previous predictions of ANSYS or the theoretical values. Exploratory calculations of a single crack under thermal loading have shown that the crack initiation and crack propagation pattern agree with the experimental observations.