Stone–Wales defect interaction in quasistatically deformed 2D silica

Abstract

In the present article, we investigate the effect of two interacting Stone–Wales defects on the deformation and fracture behaviour of 2D silica. For this purpose, we use molecular simulations based on a recently developed Yukawa-type potential function that allows for the description of silica in two dimensions. Our main objective is to address the impact of the spatial arrangement of defects on the deformation and fracture behaviour of 2D silica. To this end, we prepare various 2D silica configurations with one and two Stone–Wales defects, while varying the spatial arrangement of the two defects. The samples are subjected to athermal quasistatic tensile deformation until fracture occurs. We show that, by introducing Stone–Wales defects, both the tensile strength and tensile strain of 2D silica decreases. However, we report that not only the number of Stone–Wales defects but also the distance between them, their orientation and additionally the loading direction play an important role in the deformation and fracture behaviour of 2D silica. We discuss and explain the respective stress–strain relation by evaluating the non-affine displacement field of each configuration under tensile deformation. We observe that under certain orientations and distances 2D silica containing two Stone–Wales defects may exhibit a higher tensile strength than 2D silica with a single Stone–Wales defect.