Understanding the Anisotropic Mechanical Behavior of Single-Crystalline Alpha Quartz From the Insight of Molecular Dynamics

Abstract

Quartz is among Earth's most abundant minerals, which has several stable polymorphs in nature. In this study, molecular dynamics simulations are used to investigate the mechanical properties of crystalline alpha quartz. The obtained results specify that tensile stress under uniaxial tension is greater in z (c-axis) than in other directions (290 vs. 115 GPa and 190 GPa). This outcome confirms that crystalline quartz has an anisotropic behavior under applied load, and as a result, Young's modulus varies in different directions. Furthermore, the effect of existing central cracks with different lengths are considered and the results analyzed. According to the results, central cracks decrease average stress and strain, and this reduction is higher in the z-direction([0 0 0 1]). Additionally, it was found that the strain rate affects the stress-strain behavior of the models; however, the strain rate plays a negligible role when the central crack length extends. In terms of potential energy, simulation results indicate that potential energy is the highest in the model without any crack and reduces by growing the central crack size. © 2022. American Geophysical Union. All Rights Reserved.