Identification of the Quasi-Static and Dynamic Behaviour of Projectile-Core Steel by Using Shear-Compression Specimens

Yannick Duplan,Dominique Saletti,Pascal Forquin

doi:10.3390/met9020216

Abstract

Armour-Piercing (AP) projectiles constitute a major threat to be considered for the design of bi-layer-armour configurations constructed using a ceramic front plate backed with a composite/metal layer. When they are not made of tungsten-carbide the cores of these projectiles are made of hard steel, and are the main part that defines the penetration performance of the projectile. However, due to specific testing difficulties, the dynamic behaviour of these high-strength steel AP projectiles has not been investigated in sufficient detail. In this study, a detailed experimental investigation of the dynamic behaviour of the steel used for the steel core of 7.62 mm BZ-type AP projectiles was analysed through the use of Shear-Compression Specimens (SCS). In this study, results from both quasi-static and dynamic experiments were examined. The data processing method employed was set and validated based on numerical simulations. Both quasi-static and dynamic SCS experiments were done with the steel tested which clearly indicated the steel cores exhibit a very high elastic limit, little strain-hardening, and very little strain-rate sensitivity despite the wide range of strain-rates considered. This experimental characterisation paves the way to the numerical modelling for the analysis of ballistic impact of 7.62 mm AP projectile against lightweight armour configurations.

Highlights

For several decades, lightweight armour configuration solutions have been developed as a method to arrest small to medium calibre Armour-Piercing (AP) projectiles
The force-displacement response is plotted so the equivalent plastic
The mechanical characterisation of very high strength steel used for the projectile core of AP

Summary

Introduction

Lightweight armour configuration solutions have been developed as a method to arrest small to medium calibre Armour-Piercing (AP) projectiles Among these armour configuration solutions, the most widely used is the bi-layered configuration, which is constructed using a ceramic material for the front impact plate, and a composite or metal back plate. During the impact of an AP projectile against a bi-layered configuration, intense damage mechanisms develop simultaneously in both the target and projectile producing intense fragmentation of the ceramic front plate of the target along with brittle failure of the projectile’s core. Several authors have investigated the deformation and failure modes of AP projectiles impacting bi-layered target configurations Among these studies, the penetration process in targets made of alumina ceramic backed with an aluminium plate was investigated by den Reijer (1991) [1] considering three types of projectiles. The three projectiles considered were a medium yield strength (1.03 GPa) 6 mm blunt circular-cylindrical rod, a 7.62 mm AP hard steel core projectile, and a Metals 2019, 9, 216; doi:10.3390/met9020216 www.mdpi.com/journal/metals

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Results

Conclusion