Progressive Damage and Crack Propagation Analysis of Composite-Patched Aluminum Plate with 3D Inclined Crack under Fatigue Loading

Abstract

Fatigue crack growth and damage of adhesive layer in a composite-patched aluminum plate with three dimensional inclined crack was simulated using Extended Finite Element Method (XFEM) and Cohesive Zone Model (CZM). A Python script was developed to model fatigue crack growth using XFEM in ABAQUS environment. Three adhesive materials and five patch lay-up sequences were considered to investigate the size and shape of damaged (debonded) region in different configurations. The effect of including damage in adhesive layer on global response of the structure and 3D crack geometry in metallic structure was studied. The interaction between crack growth in bulk material and damage in adhesive layer was discussed. It was concluded that neglecting damage in adhesive layer results in 8.4 to 23.2 percent overestimated fatigue life for different sample configuration. Smoother crack geometry was obtained from damage-including models with respect to models that do not include damage. Crack front shape was also highly affected, despite the fact that the effect on crack trajectory was not significant. It was also observed that in specimens with lower final strength and high ductility adhesive, structural response is resulted from an interaction between damage in adhesive and crack growth in bulk material.