OPTIMAL CURE CYCLES FOR THE FABRICATION OF THERMOSETTING-MATRIX COMPOSITES

Polymer-matrix composites using thermosetting resins as the matrix are increasingly finding use. However, a major impediment to their widesp read commercial use is the high cost associated with their manufacture , arising from the long processing cycle times. This paper addresses t he problem of determining cure temperature and pressure variations wit h time for a time-optimal manufacture of thermosetting-matrix composit es subject to practical constraints. The optimal cure cycles are deter mined using the nonlinear programming scheme of sequential quadratic p rogramming combined with a physical model base to simulate the process phenomena. The optimized cycles are shown to improve upon the manufac turer-recommended cycles as well as the improved cycles reported in th e literature. The optimization results are reported for a wide range o f resin materials, product specifications, and process constraints to illustrate their effects on the optimal cure cycles. Parametric studie s are presented in terms of dimensionless groups to assess the combine d effects of the product and process variables on the optimal cycles i n a generalized manner.