Optimum in situ strength design of laminates under combined mechanical andthermal loads

In this paper, optimum laminate configurations are sought for multidirectio nal fibre-reinforced composite laminates under combined in-plane mechanical and thermal loads. The design objective is to enhance the value of the loa ds over and above the first-ply-failure loads which are judged by a transve rse failure criterion and the Tsai-Hill criterion, respectively. The in sit u strength parameters previously obtained are incorporated in these criteri a. It is found that the optimum designs under combined mechanical and therm al 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 signif icantly larger than those for a quasi-isotropic design. (C) 2000 Elsevier S cience Ltd. All rights reserved.