Shear failure mechanisms and influences of overlaminate configuration on the failure of composite π joints

All-composite adhesively bonded π-shaped joints, designed for integrated composite structures, have attracted increasing attention on account of their excellent mechanical behaviors. In this study, shear behaviors and failure mechanisms of two types of composite π joints made up of different overlaminates and configurations have been studied by static experiments accompanying with numerical progressive damage analyses. Good agreements between the numerical and experimental results validate the effectiveness of the numerical models and also give convincing proof of the predicted shear behaviors as well as failure mechanisms. Further the influences of overlaminate configurations on the failure of π joints were also investigated to improve their shearing load bearing capacity. It follows that the overlaminates and configurations have remarkable influences on the damage onset, propagation, and ultimate collapse patterns of the composite π joints. The adoption of the base laminate and enlargement of the filler radius and horizontal length of the L laminate in some extent could help to improve the load bearing capacity of the composite π joints.