Towards Toughening and Understanding of Silica Aerogels: MD Simulations

Abstract

This presentation focuses on Molecular-Dynamics simulations of silica. It is aimed at shedding light on the stiffness, strength, and toughness of silica, chemically modified silica and ultimately of the silica-based aerogel. Various aspects of the simulation process will be discussed, such as the methods used for creating amorphous silica, applying strain, maintaining an isothermal condition, and so on. Results will be presented for amorphous silica. This is preliminary work leading towards the first author’s dissertation. Future work will be briefly summarized.

Structure and mechanical properties of silica aerogels and xerogels modeled by molecular dynamics simulation

“…The strain rate is larger than the one used in laboratory tests; however it has been shown that smaller values of strain rate do not change the results significatively [33]. At higher strain rates, the speed of the atoms, and consequently the temperature of the sample, tend to increase.…”

“…Previous studies on modeling bulk silica where used to select the combination of strain rate and the damping to use in the Langevin dynamics without affecting the results of the simulation [33].…”