Curing of Epoxy Matrix Composites

Models were developed which describe the curing process of composites constructed from continuous fiber-reinforced, thermosetting resin matrix prepreg materials. On the basis of the models, a computer code was developed, which for flat-plate composites cured by a specified cure cycle, provides the temperature distribution, the degree of cure of the resin, the resin viscosity inside the composite, the void sizes, the temperatures and pressures inside voids, and the residual stress distribution after the cure. In addition, the computer code can be used to determine the amount of resin flow out of the composite and the resin content of the composite and the bleeder. Tests were performed measuring the temperature distribution in and the resin flow out of composites constructed from Hercules AS/3501-6 graphite epoxy prepreg tape. The data were compared with results calculated with the computer code for the conditions employed in the tests and good agreement was found between the data and the results of the computer code. A parametric study was also performed to illustrate how the model and the associated computer code can be used to determine the appropriate cure cycle for a given application, which results in a composite that is cured uniformly, has a low void content, and is cured in the shortest amount of time.