A Quantitative Damage Tolerance Comparison of High Strength and High Modulus Carbon Fiber Sandwich Structure

This study presents experimental results of the compression after impact (CAI) testing of sandwich structure with face sheets made either with IM7/8552 high strength fiber or HM63/8552 high modulus fiber. While the HM63/8552 face sheet sandwich specimens would not be as damage tolerant as the IM7/8552 face sheet sandwich specimens, a quantitative measure of how much more damage tolerant the IM7/8552 face sheets were than the HM63/8552 face sheets was sought. Due to the IM7/8552 face sheets being 28% thicker than the HM63/8552 face sheets, the impact energies used needed to be adjusted for a fair comparison. The results show that the modulus is 35% lower for the IM7/8552 face sheet sandwich structure while the CAI strength