Thermal cycling of carbon/epoxy laminates in neutral and oxidative environments

Dealing with the “French Supersonic Aircraft Research Program”, thermal cycling tests in two environments, neutral (nitrogen) and oxidative (air), were performed on three different carbon/epoxy laminates: [03/903]S, [453/−453]S and QI [45/0/−45/90]S. This experimental study was conducted following a local approach through microscopic observations and X-radiographs and showed a significant effect of the oxygen level on the damage development. In fact, observations have shown an acceleration of matrix cracking process and important matrix shrinkage due to coupling between oxidation phenomenon and cyclic thermal stresses. Moreover, the influence of orientation and thickness of the layers on the damage has been demonstrated through the comparison of the different stacking sequences.