Influence of the fibre orientation on the lap shear strength and fracture behaviour of adhesively bonded composite metal joints at high strain rates

A significant influence on the strength of adhesively bonded fibre-reinforces plastics is the local ply orientation of the adherend, especially in a hybrid or multi-material joint. In this paper, the joint strength and failure behaviour is investigated for different ply orientations using single lap shear tests. The tests are performed with quasi static loading and also under high strain rates. Digital image correlation is used to monitor the specimen deformation and separation. Analysing the cracking process, a distinction between the appearance of a cohesive failure pattern and an actual cohesively progressing failure can be made. This provides an insight to the fracture mechanics and allows a comparison between high and low strain rates. A correlation between the cracking behaviour and the maximum load and displacement is observed.