Computational Techniques for the Thermostructural Analysis of Composites

摘要

A thermomechanical cohesion-decohesion constitutive law is postulated for interface elements to predict the initiation and propagation of delamination. An exponential function is used for the constitutive law that naturally satisfies a mixed mode fracture criterion for the progression of delamination. The formulation was modified to allow for independent specification of the initial material tangent stiffness. A thermal model was implemented within the constitutive behavior of the element to simulate perfect thermal conductance prior to delamination and thermal contact conductance after delamination formation. A new failure model was implemented in the cohesion-decohesion constitutive formulation to enable the prediction of brittle compression failure. Finally, temperature-dependent emissivity for radiation calculations and temperature-dependent heat flux for high heating rates were implemented in a finite element software. The failure sequence of a composite plate with a tile repair is simulated with a fully-coupled thermal and stress progressive failure analysis, successfully demonstrating how the thermal and stress solutions affect each other.