Failure Analysis of a Graphite/Epoxy Laminate Subjected to Combined Thermal and Mechanical Loading

Quasi-static thermal stress response and failure behavior of graphite/epoxy lam inated plates under combined intense thermal and mechanical loadings are investigated. The temperature field is obtained by using a one-dimensional finite difference code. The effects of ablation, degradation of thermophysical properties at elevated tem peratures, and radiation and convective heat losses are included in the formulation. In the thermal stress and strength analyses, the temperature-dependent mechanical prop erties and temperature-dependent strengths are used. A nine-node isoparametric finite element is employed to calculate the structural responses. The maximum stress criterion is adopted for failure predictions. Numerical results include the temperature distributions over the thickness of the plate, structural responses, and time to failure. The analytical predictions are compared with experimental data.