Effect of unbonded areas around hole on the fatigue crack growth life of diffusion bonded titanium alloy laminates

Preformed unbonded areas at the interfaces of diffusion bonded titanium alloy laminates can disturb the stress distribution in their neighborhood, thus changing the crack growing characteristics. We investigated the influence on the crack growth characteristic of unbonded areas' geometric parameters using the extended finite element method (XFEM). First, the effectiveness of the method was validated through the results comparing with experiment. Second, how the unbonded areas' sizes and locations along thickness affect the crack growth was analyzed under tension-tension cyclic loading. The numerical results showed the unbonded areas can effectively block the crack growth, and prolong the fatigue life.