Investigation on Fragmentation of Pyrophoric Alloy Samples during Taylor Test Using SPH

Evaristo Santamaria Ferraro,Marina Seidl,Tom De Vuyst

doi:10.1051/epjconf/202125002008

Abstract

This study is the first part of a project that aims to assess and model impact-induced energy release (IIER). The present part of the work investigates the failure mode of brittle commercial pyrophoric alloy samples during Taylor impact tests. A series of ferrocerium specimens were shot against tungsten carbide anvils, with velocities ranging between 60 and 140 m/s. A Total Lagrangian SPH model was employed to simulate the deformation and impact-induced fragmentation of the cylinders using LSDYNA®. The modified Johnson-Cook constitutive model was applied in combination with the Cockcroft-Latham fracture criterion. The plastic deformation process, shear cracking, and fragmentation are well reproduced in the numerical results.

Highlights

The work discussed in this paper is the first step of a broader project aiming to investigate and model Impact Induced Energy Release (IIER) of Intermetallic Reactive Materials (IRM)
Brittle fracture and impact-induced energy release were observed for impact velocities in the range of 73 m/s to 140 m/s
The Total Lagrangian Smoothed Particle Hydrodynamics (SPH) model was proven to be adequate in reproducing the small plastic deformation experienced at lower velocities by the samples

Summary

Introduction

The work discussed in this paper is the first step of a broader project aiming to investigate and model Impact Induced Energy Release (IIER) of Intermetallic Reactive Materials (IRM). The improvement in material design and manufacturing drove the attention of defence industry towards IRM in recent years, as they show interesting mechanical properties combined with the capability to release energy when stimulated [1]. IRM are stable in normal conditions, allowing relatively safe handling. This preliminary study is performed using Ferrocerium, a commercially available brittle pyrophoric mixture of rare earths, mainly cerium (Ce, 49%) and lanthanum (La, 23%) [2], with mechanical properties comparable to common IRMs, which releases energy upon impact. Ferrocerium is used in this work as a surrogate material to set up the academic study and evaluate the methodologies necessary for data extrapolation and further progression of the research. This work focuses on a series of Taylor impact tests performed to examine the failure mode and its evolution for Ferrocerium bars

Methods

Results

Conclusion