Effects of static preloads on the high velocity impact response of composite plates

The paper discusses a high velocity impact scenario where representative fuselage composite plates are statically preloaded and then impacted with a blunt impactor at velocities in the range 70-105 m/s. Compression and tension preloads that represent design limit load were considered as well as lower preloads that a structure would carry more frequently. Gas gun impact tests were performed to generate a validation database for comparison with results from numerical simulation. A modelling methodology to simulate preloads and transient impact events was documented. The numerical model captures intra- and inter-ply damage by using layers of shell elements connected with cohesive interface layers. Both test and simulation results indicate an influence of static preloads on the impact damage response. The numerical model was especially used to better understand the interaction between preloads and dynamic impact loads which are complex especially for impact on buckled plates.