Residual thermal stresses in an unsymmetrical cross-ply graphite/epoxy laminate

This paper presents an exploratory i nvestigation of the residual stresses in AS-3502 graphitel epoxy laminates due to cool-down from their cure temperature. Emphasis is placed on the significance of time-dependent material behavior and the potential utilization of this phenomenon to reduce residual stresses by a j udicious choice of the cool down process. The analysis considers the time-dependent behavior of the material and all calculations employ recent data on the thermoviscoelastic response of the AS-3502 graphite/ epoxy system. The viscoelastic analysis is verified through curvature measurements of unsymnetric cross-ply plates fabricated from the AS-3502 graphi telepoxy material