Influence of inclusion size and strain rate on the interaction between cracking and the matrix–inclusion interface in composites

The critical deflection/penetration behaviour of a crack terminating perpendicular to a circular matrix–inclusion interface under dynamic tensile loadings is simulated numerically. It is found that higher strain-rate loading is necessary for a crack to penetrate through an inclusion with a smaller radius. Moreover, the minimum loading amplitude for penetration increases with the strain-rate, and this strain-rate dependence appears to be independent of the inclusion size and the interfacial strength. Additionally, these results imply that the strain-rate effect of dynamic strength can be induced by the quasi-static structural properties of composites, which is in agreement with the results of previous works.

► Strain rate and inclusion size affect deflection/penetration behavior of crack perpendicular to circular interface.
► Critical strain rates decreasing with inclusion size exist for crack penetration, and crack deflection is shear dominated.
► Strain rate dependence of Second Phase Dynamic Strength is independent of both inclusion size and interfacial strength.
► Strain rate effect on strength isn’t an intrinsic property of composites, due to dependence on external loading conditions.