Failure mechanism of single lap, adhesively bonded composite-titanium joints subjected to solid projectile impact

The failure mechanism of single lap, adhesively bonded composite-titanium joints subjected to solid projectile impact is addressed in this article. Three-dimensional finite element analysis was conducted in Abaqus/Explicit using two damage models. The first damage model accounts for debonding failure modes of adhesive–adherend interface using cohesive zone method. The second damage model accounts for in-plane failure modes of composite adherend using Hashin criterion and continuum damage mechanics. Mechanical tests were carried out by impacting the adhesively bonded joints with solid projectile using a one-stage gas gun. The recorded strain responses and damage patterns were found to be in good correlation with those of the finite element analysis. Results have shown that, for single lap, adhesively bonded composite-titanium joints under increasing impact velocities of solid projectile, the progression of failure modes is: local debonding in the adhesive–titanium adherend interface, matrix cracking in the composite adherend and global debonding in the adhesive–titanium adherend interface.