An efficient thermal cure profile design method for autoclave curing of large size mold

Abstract

The mold temperature uniformity has a crucial effect on the quality of composite part manufactured by the autoclave curing process, especially for large size mold. It has been a challenging issue to design appropriate thermal cure profile not only improving the temperature uniformity but also reducing the manufacturing cost. This paper aims to provide a fast and reliable thermal cure profile design method considering the actual autoclave curing condition and the thermal behavior of the curing mold. Firstly, a computational fluid dynamic (CFD)-based autoclave simulation model is established for a large framed mold and validated. Which offers reliable evaluation about the thermal behavior and heat transfer coefficient (HTC) of the curing mold. Then, a novel method is introduced using unit volume element-based simulation to represent the highest and the lowest temperature histories of the mold top surface as accurately as the CFD-based simulation but with huge reduction in computation time. Finally, thermal cure profile optimization is performed combining genetic algorithm (GA) and the unit volume element method to reduce temperature gradient and cure time simultaneously as the temperature uniformity governs the final part quality and the cure time governs manufacturing cost. The optimization results showcase the benefits of well-designed thermal cure profile for improving the autoclave curing process and the proposed design method can be applied to various large size molds for manufacturing large composite parts.