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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. [ABSTRACT FROM AUTHOR]

A numerical strategy, based on continuum damage mechanics and the failure envelope method, is proposed for failure prediction of composite multi-bolt joints. First, the design parameters of the failure envelope are determined by virtual tests of simple structures. Then, a modified failure envelope incorporating the bending effect is constructed. Finally, different bearing-to-bypass stress ratios and the influence of bolt rows on the bending effect are discussed. It is shown that the failure envelope with constant bearing-to-bypass stress ratio, obtained by assuming uniform bolt load distribution, is recommended. And the bending effect of single-lap, composite multi-bolt joints is alleviated by the introduction of more bolt rows. These results indicate that failure prediction of composite multi-bolt joints, using the proposed numerical strategy, exhibits excellent agreement with the experimental outcomes. This demonstrates that the numerical strategy is feasible. [ABSTRACT FROM AUTHOR]