Optimal curing for thermoset matrix composites: Thermochemical considerations

A design sensitivity analysis is used to optimize the applied wall temperat ure vs. time in autoclave curing for thermoset matrix composites. The calcu lation minimizes the cure time and obeys a maximum temperature constraint i n the composite. The transient, coupled thermal and cure problem is solved by a finite element method. Design sensitivity information is extracted eff iciently from this primal analysis, based on an analytical, direct differen tiation approach. The sensitivities are then used with gradient-based optim ization techniques to systematically improve the curing process. The optima l cure cycles for different numbers of temperature dwells may be similar (f or a 2 mm thick part) or very different (for a 4 cm thick part), depending on the nature of the problem. in the latter case a large reduction of cure time is obtained when a three-dwell cure cycle is used, and the optimizer h as more flexibility to adjust the cure cycle. This systematic optimization approach provides a powerful and practical means of optimizing composite ma nufacturing processes.