Geometry-Dependent Crack Interaction and Toughening in Graphene

TL;DR

This study uses computational simulations to explore how crack width and spacing affect the fracture behavior of graphene, revealing that wider cracks can significantly enhance toughness and ductility.

Contribution

It introduces a detailed analysis of crack width effects on graphene fracture, highlighting the importance of crack geometry in toughness enhancement.

Findings

Increasing crack width amplifies sensitivity to crack spacing.

Wider cracks lead to delayed ligament rupture and ductile fracture.

Normalized toughness exceeds that of single-crack systems by over two times.

Abstract

The interaction between neighboring cracks has been shown to strongly influence the fracture behavior of graphene. While previous studies focused primarily on crack spacing, the role of crack width remains poorly understood. Here, computational simulations are performed to investigate the coupled effects of crack width and inter-crack spacing $(W_\text{gap})$ on the tensile response of graphene containing parallel cracks. The results show that increasing crack width amplifies the sensitivity of mechanical properties to crack spacing, leading to significant enhancement of peak stress, fracture strain, and toughness at sufficiently large $W_\text{gap}$. For narrow cracks, crack coalescence dominates and causes brittle failure. In contrast, wider cracks promote delayed ligament rupture, increased energy absorption and ductile-like fracture behavior. The normalized toughness and fracture strain exceed those of equivalent single-crack systems by more than twofold. A crack-geometry design map is proposed to identify regimes of crack coalescence, independent propagation, and enhanced toughness.