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The Mechanism of Plate Penetration and Failure

Introduction to The Mechanism of Plate Penetration and Failure

hen an armour piercing projectile penetrates armour plate, the penetration usually occurs in one of a few quite characteristic ways, the actual mode of failure depending upon the nature of the plate. In this article the various common modes of penetration are described, and an explanation of the way in which plate properties determine the nature of penetration. The armour piercing projectile is considered to be perfect and to suffer no fracture, deformation or shatter; this is not necessarily so, but other articles will describe typical forms of projectile failure and their effects upon penetration.

The pages in this article are:

• This Introduction.
• Defining a Few Terms
• Overview
  • Formation of Petals on Plate Front
  • Formation of a Bulge on the Back Face
  • Star Crack and Back Petal Formation
  • Plug Formation
  • Failures Peculiar to Rolled Homogenous Armour
  • Failures Peculiar to Cast Armour
• Failures Peculiar to Thin Plates
• Equations Describing Normal Attack by Kinetic Energy Projectiles
• Attack at Oblique Angles up to 30°
• Attack at Oblique Angles Beyond 30°
• Reaction on the Projectile
• The Effect of Projectile Head Shape
• Attack by Sub-Calibre Projectiles
• Equations Describing the Effect of Obliquity on All Anti-Armour Projectiles
• Works Cited by this Article.

This article is taken mostly from C. Sykes et. al. The Penetration of Armour Plate. This report is very dense and I have done my best to simplify what can, at times, be very technical. Thankfully the diagrams in this report are excellent, and I have reproduced most of them in this article. Information on modern ammunition comes mostly from Richard M. Ogorkiewicz’ Technology of Tanks. These and other sources used are cited in the endnotes.

A big thank you to Chris Shillito who generously provided most of the photographs.

What to do if you find this topic a bit over your head — don’t panic! I have eliminated nearly all the mathematics and simplified the text, but this is still a very technical subject. However, nearly every page has a clear diagram and/or a photograph of actual damage with a simplified description, so you may find it useful to skim the text and look at the illustrations. By doing this you’ll gain a good overview of the different types of armour plate failure, and be able to recognise them when you see a damaged tank in a museum. Best of all, you’ll come to appreciate how complicated this topic is and, I hope, when you re-read the text more of it will sink in than trying to get it all the first time around. There is no exam, so enjoy!

Defining a Few Terms

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