Fragmentation processes in impact of spheres

TL;DR

This study uses 3D discrete element simulations to analyze the fragmentation of spheres upon impact, revealing detailed crack development, fragment distribution, and impact energy effects, enhancing understanding of impact fracture mechanisms.

Contribution

It introduces a detailed 3D DEM model that captures the development of meridional cracks and fragment distributions, aligning with experimental observations.

Findings

Meridional cracks initiate inside the sphere with quasi-periodic angular distribution.

Fragment mass distribution shows a broad peak fitted by Weibull distribution.

Results are consistent regardless of disorder degree in the model.

Abstract

We study the brittle fragmentation of spheres by using a three-dimensional Discrete Element Model. Large scale computer simulations are performed with a model that consists of agglomerates of many particles, interconnected by beam-truss elements. We focus on the detailed development of the fragmentation process and study several fragmentation mechanisms. The evolution of meridional cracks is studied in detail. These cracks are found to initiate in the inside of the specimen with quasi-periodic angular distribution. The fragments that are formed when these cracks penetrate the specimen surface give a broad peak in the fragment mass distribution for large fragments that can be fitted by a two-parameter Weibull distribution. This mechanism can only be observed in 3D models or experiments. The results prove to be independent of the degree of disorder in the model. Our results significantly improve the understanding of the fragmentation process for impact fracture since besides reproducing the experimental observations of fragment shapes, impact energy dependence and mass distribution, we also have full access to the failure conditions and evolution.