Damage tolerance analysis of adhesively bonded composite single lap joints containing a debond flaw

Adhesive bonding technology is being increasingly used in the assembly and repair processes of composite structures. The existence of debond flaws weakens the performance of adhesively bonded structures. This article presents the results from an investigation into the effects of debond flaws on the mechanical performance of adhesively bonded single lap joints. The experimental results show that both the load-carrying capability and the failure mode of the single lap joints vary with the location of the debond flaws. Three-dimensional progressive damage finite-element models were developed in ABAQUS to simulate the tensile behaviour of single lap joints. The simulation results agree with the experimental data. The flaws located at 1/4 lap length result in a more pronounced reduction in the load-carrying capability than those located at the edge and the middle portion of the bond region. Compared with the other two locations, the residual strength of the single lap joint with a flaw at 1/2 lap length possesses a higher value. Moreover, the effects of flaws on strength reduction are more prominent for damage propagation than damage initiation.