Study of Mechanical Properties of Silicate Minerals by Molecular Dynamics Simulation

The aging and damage of concrete buildings and structures is a problem in modern society. This is especially true for nuclear power plant buildings, which are required to have high safety standards. In this study, molecular dynamics simulations were performed to obtain mechanical properties for silicate minerals, including quartz, which is used as an aggregate in concrete. We also attempted to clarify phenomena including mechanical fracture. Mechanical properties of each mineral (Young's modulus, Poisson's ratio, and maximum stress) were obtained by performing tensile simulations on 10 silicate minerals which are -quartz, Orthoclase, Microcline, Albite, Oligoclase, Andesine, Labradorite, Augite, Diopside and Forsterite. Minerals other than -quartz were highly anisotropic with respect to Young's modulus. The maximum stress was highest for -quartz, but once a fracture started, the development of large fractures progressed at once and the stress relaxed rapidly. Deformation and fracture of the mineral in response to strain were analyzed by extracting the nonaffine component of the local displacement of atoms in tensile simulations. This analysis was able to explain the behavior of the stress-strain curve for each mineral. We also investigated how the composition of a mineral affects its mechanical fracture.