Universal shielding effect of curvature on two interacting cracks

Abstract

The interaction of approaching cracks plays a crucial role in the formation of complex crack patterns in the mechanics and physics of materials defects. While curvature has been shown to be important in the growth, interaction, and ordering of various defects, its influence on the interactions of multiple cracks remains poorly understood. In this study, we investigate how two approaching cracks interact in curved sheets using an integrated mechanical framework combing experiments, fracture phase-field simulations, and theoretical analysis. Our findings demonstrate that the repulsive and attractive interactions between the two initially parallel cracks are significantly shielded by curvature. This shielding effect arises because curvature alters the stress fields at the crack tips and reduces the initial deflection angle of the crack tips. We observe this effect under different initial crack positions, material properties, and curved configurations, indicating a general role of curvature in controlling the paths and interactions of cracks. This study provides insights into understanding the interaction of approaching cracks, which has implications for fracture and fatigue control.