Dynamic effects of inclusions and microcracks on a main crack

The shielding and amplification effects of multiple inclusions and microcracks on the tip or the growth path of a main crack under dynamic loading are investigated using numerical simulations. The simulations employ a combined numerical tool based on the time-domain boundary element method together with the sub-region technique for multi-regions, the maximum circumferential stress criterion for crack-growth direction and discrete modelling for the crack propagation. New elements of constant length are added to the moving crack-tip to simulate the growth at an adaptable time-step according to the crack propagation criterion. Of particular interest is the study of the effects of the sizes and positions of inclusions and microcracks and the material combinations on the dynamic stress intensity factors and the crack growth path. The numerical results demonstrate the crack-tip shielding and amplification effects of inclusions and micro-cracks.