The critical role of the interaction potential and simulation protocol for the structural and mechanical properties of sodosilicate glasses

TL;DR

This study evaluates how different interaction potentials and simulation protocols influence the predicted structural and mechanical properties of sodosilicate glasses, emphasizing the importance of ensemble choice and system size.

Contribution

It systematically compares various potentials and simulation conditions, highlighting their impact on mechanical property predictions and providing guidelines for accurate fracture simulations.

Findings

Mechanical properties vary significantly with the potential used.

Samples of at least 75,000 atoms are necessary to mitigate finite size effects.

Fracture simulations are most reliable in the constant pressure ensemble.

Abstract

We compare the ability of various interaction potentials to predict the structural and mechanical properties of silica and sodium silicate glasses. While most structural quantities show a relatively mild dependence on the potential used, the mechanical properties such as the failure stress and strain as well as the elastic moduli depend very strongly on the potential, once finite size effects have been taken into account. We find that to avoid such finite size effects, samples of at least 75,000 atoms are needed. Finally we probe how the simulation ensemble influences the fracture properties of the glasses and conclude that fracture simulations should be carried out in the constant pressure ensemble.