MOLECULAR DYNAMICS OBSERVATION OF DISCRETENESS OF THE MASS DISTRIBUTION DURING NANOSCALE FRAGMENTATION

Abstract

Molecular dynamics simulations of the rigid-anvil collision test are performed by using a two-dimensional computational setup that mimics the traditional ballistic Taylor test. In this extensively utilized computational setup, the slender nanoscale projectiles collide with a rigid wall with hypersonic striking velocities ranging from 3 km/s to 30 km/s. The projectiles used in these simulations are flat-ended, monocrystalline, nanoscale bars prepared at zero temperature. The Poisson hyper-exponential distribution with the logarithmic binning is used to capture the fragment mass (size) distribution under the constraint of the relatively small specimen size 15×100 nm. The objective is to highlight the occurrence of certain discreteness of the fragment mass distribution observed both in time (during the fragment debris evolution) and across the striking velocity field (for the final fragmentation states that correspond to the stationary distributions).