Curing in Thick Composite Laminates: Experiment and Simulation

Abstract

Thick part ( > 5 cm) temperature profiles were obtained from a one- dimensional experiment. These results are compared with the predictions of a computer simulation containing improved and existing models for extent of reaction, viscosity and other composite properties of the same resin/fiber system. In particular the simulation recovers the thermal behavior of a 5 cm thick, unidirectional Hercules AS-4/3501-6 graphite/epoxy composite laminate. Application of consolidation pressures based on pre dicted viscosities led to dramatic improvement in void content of a real laminate. The sim ulation is used to investigate important processing variables and changes in chemo rheology and temperature in a thick section laminate during cure. The following results are found: imtial extent of reaction is relatively unimportant; consolidation is important; the peak temperature originates near the surface of the laminate and propagates to the center; asymmetric temperature application changes the viscosity and cure profiles; vis cosity never reaches low values simultaneously through the thickness in laminates in ex cess of 10 cm thickness.