Modeling of crack path in layered architectures composed of dissimilar materials

In order to make full use of the potential fatigue crack growth resistance provided by layered architectures, a validated crack path simulation algorithm for crack propagation through different elements of the layered architectures was established. The crack path approaching a material interface was predicted by using the maximum tangential strain (MTSN) criterion and the crack behavior at the interface was simulated by a developed two-step method (a modified stress-and-energy-based cohesive zone method considering the change in direction of an interface penetrating crack). The crack path simulation by using this algorithm in layered example architectures indicates (1) there are two criteria zones for the transition between crack deflection and penetration in terms of the relationship between interfacial strength and toughness; (2) the likelihood of a crack deflecting out of the interface will increase with the propagation of an interfacial crack; and (3) the architecture difference which affects shielding or anti-shielding behavior has a significant effect on crack deflection or penetration events.