Optimum in situ strength design of laminates under combined mechanical and thermal loads

In this paper, optimum laminate configurations are sought for multidirectional fibre-reinforced composite laminates under combined in-plane mechanical and thermal loads. The design objective is to enhance the value of the loads over and above the first-ply-failure loads which are judged by a transverse failure criterion and the Tsai-Hill criterion, respectively. The in situ strength parameters previously obtained are incorporated in these criteria. It is found that the optimum designs under combined mechanical and thermal loads are not the same as those under pure mechanical loads for three of the four loading cases studied. For ail cases the optimum loads are significantly larger than those for a quasi-isotropic design. (C) 2000 Elsevier Science Ltd. All rights reserved.