Shattering impact fragmentation of slender nanoprojectiles

Abstract

Molecular dynamics simulations of the rigid-anvil collision test are performed to achieve the complete pulverization of slender nanoprojectiles. The simulation setup mimics the traditional Taylor test (the flatended nanoscale bars collide with a rough rigid wall) at striking velocities that reach an awesome range from 20 km/s to 120 km/s. The objective is to investigate, so called, shattering fragmentation, defined by the complete disintegration (pulverization) of the slender monocrystalline nanoprojectile into the cloud of monatomic debris (mmax = mmax1 ≡ 1). The critical impact energy associated with this transition from the stochastic to the deterministic fragment distribution is investigated at two widely different initial temperatures of the slender nanoprojectile while scaling its size in a self-similar manner by varying their widths (diameters) at a fixed aspect ratio. For all but the smallest nanoprojectiles, the minimum achievable mmax >> mmax1 is discussed based on the physically-limiting striking velocity range.

On critical exponents for impact fragmentation of spherical solids

“…Molecular dynamics (MD) [12,16], discrete element models (DEM) [5,6,17,18], and SPH method [10,13,15] are used to simulate fragmentation numerically. The choice of the particle- An important feature of the SPH method is that a proper SPH lattice should be as regular as possible and not contain large discrepancies in order to perform most accurate simulation [19,20].…”