When a material is subjected to external loading, the crack within the interface region can often either deflect or penetrate (among other failure mechanisms such as renucleation or bifurcation) , depending on the nature of the load and the properties of the material. Deflection is a desirable property in certain materials or structures, as it can often be directly related to material toughening. In composites, crack deflection is a key mechanism for toughening [2] . Although the requirements for a crack's deflection as it approaches a bimaterial interface is well understood, similar progress in comprehending the mechanics of "penetration of a deflected crack propagating along an interface" is paramount. However, while Deflection undoubtedly is a failure mechanism, it is a much more preferable failure mechanism compared to penetration, as deflection can prolong the life of a material through creating a less time efficient path for a crack to propagate throughout.