Mechanisms of fragmentation of Al-W granular composites under dynamic loading

TL;DR

This study uses numerical simulations to analyze how Al-W granular composites fragment under explosive dynamic loading, identifying three key mechanisms that influence fragmentation and can be controlled through initial structure.

Contribution

It introduces a detailed analysis of fragmentation mechanisms in Al-W composites under dynamic loading, highlighting mesoscale processes and their impact on fragment size control.

Findings

Three fragmentation mechanisms identified: macrocracks, voids/microcracks, mesoscale jetting.

Mesoscale mechanisms can be tailored to control fragment size.

Different mechanisms dominate under various loading conditions.

Abstract

Numerical simulations of Aluminum (Al) and Tungsten (W) granular composite rings under various dynamic loading conditions caused by explosive loading were examined. Three competing mechanisms of fragmentation were observed: a continuum level mechanism generating large macrocracks described by the Grady-Kipp fragmentation mechanism, a mesoscale mechanism generating voids and microcracks near the initially unbonded Al/W interfaces due to tensile strains, and a mesoscale jetting due to the development of large velocity gradients between the W particles and adjacent Al. These mesoscale mechanisms can be used to tailor the size of the fragments by selecting an appropriate initial mesostructure for a given loading condition.