Simulation of fastened composites subjected to Pull-Through and Shear loads

Kurzfassung

Structural integrity under impact is a considerable safety issue in transport aircraft, due to the fact that aircraft structures are vulnerable to impact damages. For this reason, aircraft structures have to satisfy certification procedures for High Velocity Impact (HVI), such as bird strike. With the aim to reduce certification and development costs, computational methods based on FEM are being developed to predict response of structures under impact. The German Aerospace Center (DLR) is active in this field since several years, particularly in material modelling, testing and FE simulation of impact damages in fibre reinforced composite aircraft structures. This report is a contribution to this ongoing research and is focused on fastened carbon fibre composite joints. Due to their relative ease of installation, resistance to creep, resistance to environmental degradation and no thickness limitation, fasteners play a crucial role in the joining of aerospace components. The understanding of stiffness, strength and failure mode of fastened joints is critical to the efficient design of composite structures. With this goal, FE simulations with PAM-CRASH have been developed to investigate the damage caused by impact in riveted composite structures under two load cases: Pull-Through and Shear Tests. Analysis is focused on ply damage and delamination of composite layers.