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Abstract

It has become possible over the last half century to provide lightweight armour capable of defeating high velocity bullets. The aim of this thesis is to study the behaviour of such armours and enhance the understanding of the mechanism by which high velocity projectiles are defeated.

In order to achieve this various aspects of the behaviour of lightweight armours and their constituent parts were studied. This study began by making flash radiograms of the penetration of three different armour constructions by high velocity projectiles. From the analysis of these radiograms the rate of penetration through the ceramic, the destruction and distortion of the projectile were studied. An empirical model of the performance of unfaced aramid laminates was produced.

Data on the performance of lightweight armours attacked at oblique angles was collected. The behaviour of the materials under these conditions was interpreted with the aid of the model of laminate performance.

The role of plate bending in the failure of the ceramic was considered. It was found that there was a critical thickness of ceramic below which bending waves did play a significant role in the failure of the ceramic facing. Above this critical thickness little evidence of plate bending was found. This postulation also rationalized the anomalies found in the analysis of the armour behaviour at oblique incidence.

The fractures induced in ceramic facings attacked by a high velocity projectile were examined. It was found that the formation of the observed fracture cone could be explained by the action of a shear wave. The observed axial cracking on the rear face of the ceramic was associated with the reflection of the dilatational wave.

Finally a model was developed which can predict the ballistic performance of a variety of ceramic facings attached to an aramid laminate backing. The level of understanding of the system was demonstrated by the close agreement between the model and the measured values for the performance of lightweight armours with several different ceramic facings.

Publication Type:	Thesis (Doctoral)
Subjects:	T Technology > TA Engineering (General). Civil engineering (General) T Technology > TS Manufactures
Departments:	School of Science & Technology > Engineering School of Science & Technology > School of Science & Technology Doctoral Theses Doctoral Theses

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