Effects of Processing Temperature and Layup on Matrix Cracking

Tests were performed to assess the effects of processing temperature and laminate layup on matrix cracking. Twelve inches long and one inch wide cross-ply and angle ply coupons made of Fiberite T300/976 graphite/epoxy were tested. Coupons of different layup were cured and postcured at different temperatures. The number of cracks was determined from X-ray pictures. The results showed that the number of cracks depends directly on the maximum temperature reached during processing, and is minimized when the 900 plies are dispersed (not stacked together) in the laminate.