Modeling and Guidelines for the Autoclave Process

The autoclave process is one of the often used production procedures for making structural composites in the aerospace industry. An autoclave is a pressure vessel that operates under control temperature and pressure.

The fabrication of composites by the autoclave process is complex. It involves simultaneous heat, mass, and momentum transfer along with chemical reactions in a multiphase system with time-dependent material properties and boundary conditions. The critical problems that arise during the production of thick composites are the occurrence of severely detrimental voids, gradients in resin concentration, unequal cure at different points in the composite, and thermal stresses. In order to efficiently manufacture quality parts, on-line control and process optimization are necessary, which in turn require a realistic model of the entire process. In the past, chemoviscosity, heat transfer, resin flow, and void growth models have been developed for thermosetting resin system. This paper reviews these models and proposes guidelines for the selection of optimum cure cycle parameters based on scientific principles.