CRANFIELD UNIVERSITY ALEXANDER JAMES MABBOTT THE OVERMATCHING OF UK

363 Pages·2016·9.16 MB·English

CRANFIELD UNIVERSITY

ALEXANDER JAMES MABBOTT

THE OVERMATCHING OF UK POLICE BODY ARMOUR

CRANFIELD DEFENCE AND SECURITY

PhD thesis
Academic Year: 2015

Supervisors: Dr Debra Carr and Mr Stephen Champion
December 2015
CRANFIELD UNIVERSITY

CRANFIELD DEFENCE AND SECURITY

PhD Thesis

Academic Year 2015

Alexander James Mabbott

THE OVERMATCHING OF UK POLICE BODY ARMOUR

Supervised by Dr Debra Carr and Mr Stephen Champion
December 2015

 Cranfield University 2015. All rights reserved. No part of this publication
may be reproduced without the written permission of the copyright owner.
ABSTRACT
Police officers and other personnel in the UK routinely wear body armour that provides
protection from specific threats. Typically, 'soft' armours, usually formed from multiple layers of
fabric, can protect wearers from fragmentation and low velocity (handgun) ballistic threats, while
‘hard’ armours, formed from ceramic and composite plates, offer protection from high velocity
(rifle) threats. Protection from stab and/or slash attack is predominantly provided by utilising
chain mail and laminated solutions. The question has been raised however, of what would happen
when armour is overmatched with a greater threat than it is designed to protect against.
A limited number of studies have been published in the open source literature regarding
the overmatching of soft body armour.
This research aims to increase the understanding of overmatching, by investigating the
effect of both i) soft fabric body armour designed to protect from handgun ammunition being
challenged by high velocity rifle projectiles and ii) knife and spike resistant armour protecting
against low velocity handgun projectiles.
A subsection of the research considered three tissue simulants in order to find the most
suitable for investigating the effects of overmatching armour. A method for recording the damage
produced in the simulants was also developed; from which comparison of damage to different
targets was possible.
Following the tissue simulant investigation, gelatine blocks 10% in concentration were
selected and used to investigate the overmatching of two types of UK police body armour. Three
different arrangements were setup, namely 10% gelatine blocks 500mm, 10% gelatine blocks
250mm in length, and porcine thoracic walls arranged to simulate a thorax.
Testing blocks 500mm in length was a set-up typical to ballistic investigations; the
blocks were capable of capturing the majority of the projectiles’ damage, with the damage
produced in both unprotected and protected (on the front face only) targets compared. Based
on anthropometric measurements, testing 10% gelatine blocks 250mm in size was more
representative of a torso sized target. With the blocks smaller, armour was placed on both the
front and back face of targets. This is more representative of how armour would be worn in a
real life scenario; patrolling UK police officer wearing armour that protects both the front and
back of their torso. Finally, the use of porcine samples arranged to simulate both protected and
unprotected thoraxes enabled comparisons of the damage seen in homogenous tissue simulants
to damage in non-homogenous material typical to those found in the human torso.
The outcomes from testing three different targets with two ammunition and armour
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combinations revealed the effect of overmatching armour is not one that can be generalised
and predicted for all overmatching scenarios. The presence of armour on the rear face of targets
based on typical measurements of human chest depth, increased the chances of the projectiles
tested remaining within the targets.
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ACKNOWLEDGEMENTS
There are only so many ways I can say thank you, and yet so many people to thank, so
please bear with me as I take this opportunity to pay tribute those who without whom this thesis
would not have been possible.
Mum and Dad: it’s done! Thank you for everything. For all the favours, from days and
nights spent correcting my use of the English language, to collecting documents on my behalf,
even when they weren’t quite as close to your location as I believed… I truly wouldn’t have
had this opportunity without your support and push to further myself. And it’s okay Dad, it got
me a job in the end! Thank you to my big sisters too. Your words of encouragement through
the toughest times were invaluable.
To Deb – I truly could not have asked for a better supervisor. You are a credit to your
profession and I know I’m not that only one who thinks so. Being fortunate enough to have
had your supervision, support, and advice has made me not only a better academic but a better
person. You work so hard, and your expertise and knowledge knows no bounds. You are a true
role model, particularly to those of us who are grammatically challenged! Thank you. I will
always, always be indebted to you, and I will come back and make gelatine for you anytime!
To Steve, for getting me involved with the mucky job that is gelatine production,
I’ve come a long way thanks to you. I may have cursed you once or twice for your ballistic and
aerodynamic input, but ultimately I am better off for the expertise you shared with me. Thank
you.
To Professor Ian Horsfall, for always being in support of the work I have carried
out for the Impact and Armour group. One of my fondest memories will always be PASS 2012.
Within the Impact and Armour group, a big thank you goes to Dave, Mike, Claire, Alan; the
range staff. For getting stuck in with me for the numerous hours I spent down the range, from
shaking gelatine out of their boxes, to holding bits of meat for photographs, nothing was too
much to ask of you, and it made my task a lot easier. Tea breaks were always a welcome break
from staring at the computer screen and always a good laugh too!
To my office buddies past and present: Rocky, Ryan, Cat and Leigh. It’s been a
long time coming and without the snacks, throw-and-catch sessions, practical jokes, tunes, late
nights and the joint suffering; I wouldn’t be writing my acknowledgments page right now.
You’re some of smartest people I’ve come across and I can’t wait to graduate with you!
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I have a few final shout-outs to my fellow Cranfieldians, who through either
assistance or friendship, made this a little easier. In particular, to Dan and Charlene, who have
been through this ordeal and come out the other side of it with flying colours. Your advice has
been invaluable, and I truly have the utmost respect for what you have achieved. Thanks also
to Iain Mackay for accepting all the challenges I posed you during the last few years.
Thank you to the Engineering and Physical Sciences Research Council for
sponsoring the project. I would also like to extend my gratitude to the Home Office’s Centre
for Applied Science and Technology (CAST) and in particular Chris Malbon, who provided
the materials needed to complete this research. Support was also provided to me by The
Worshipful Company of Armourers and Brasiers, who made it possible for me to attend PASS
2012 and 2014 to present my research. A final thank you for the support I received from the
Ballistics Injury Archive, and in particular Leslie Payne, whose knowledge was truly
invaluable during the early stages of my studies.
To the Lakers, the guys back home, and friends both sides of the Atlantic, thanks
for not getting too bored hearing about the trials of being a student, still. The professional
student career is nearly at an end and I look forward to catching up with everyone and making
up for lost time.
Last but not least, Annie. For being there through the most stressful times; being
patient, being the distraction, being the motivation, talking and listening through topics I bet
you never thought you’d hear about. Not to mention making ISB2014 the best conference
known to man. Thank you.

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CONTENTS

ABSTRACT ................................................................................................................................ i
ACKNOWLEDGEMENTS ........................................................................................................ i
CONTENTS ............................................................................................................................. iii
LIST OF FIGURES ................................................................................................................... x
LIST OF TABLES ................................................................................................................... xv
NOMENCLATURE .............................................................................................................. xxii
Chapter 1 : INTRODUCTION................................................................................................... 1
1.1 Relevance of the subject .................................................................................................. 2
1.2 Aim and outline of the study ............................................................................................ 3
1.3 Structure of the thesis....................................................................................................... 4
Chapter 2 : LITERATURE REVIEW........................................................................................ 6
2.1 Ammunition ..................................................................................................................... 6
2.1.1 Cartridge case nomenclature ..................................................................................... 6
2.1.2 Projectile ................................................................................................................... 8
2.1.2.1 Expanding projectiles......................................................................................... 9
2.1.2.2 Fragmenting projectiles ................................................................................... 10
2.1.2.3 Projectile velocity ............................................................................................ 10
2.1.3 Summary ................................................................................................................. 11
2.2 Wound ballistics............................................................................................................. 12
2.2.1 External ballistics .................................................................................................... 12
2.2.1.1 Ballistic coefficient .......................................................................................... 13
2.2.1.2 Drag force and drag coefficient ....................................................................... 14
2.2.1.3 Stability ............................................................................................................ 16
2.2.1.3.1 Yaw ........................................................................................................... 17
2.2.2 Theories of wounding capability ............................................................................ 18
2.2.2.1 Expected Kinetic Energy (EKE) ...................................................................... 20
2.2.3 Wounding mechanisms ........................................................................................... 21
2.2.3.1 Crushing and lacerating of tissue ..................................................................... 22
2.2.3.1.1 Deceleration in tissue ................................................................................ 22
2.2.3.1.2 Yawing in tissue ........................................................................................ 24
2.2.3.2 Temporary Cavitation ...................................................................................... 26
2.2.3.3 Shock waves..................................................................................................... 29
2.2.3.4 Bullet expansion and fragmentation ................................................................ 29
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2.2.3.5 Contamination .................................................................................................. 30
2.2.5 Summary ................................................................................................................. 32
2.3 Tissue simulants ............................................................................................................. 33
2.3.1 Ballistic soap ........................................................................................................... 34
2.3.2 Gelatine ................................................................................................................... 34
2.3.2.1 10% gelatine..................................................................................................... 35
2.3.2.2 20% gelatine..................................................................................................... 36
2.3.2.3 10% blocks vs 20% blocks – which blocks to use? ......................................... 37
2.3.2.4 Temperature ..................................................................................................... 38
2.3.2.5 Block size ......................................................................................................... 40
2.3.2.5.1 Anthropometric measurements of the human torso .................................. 41
2.3.2.6 Calibration........................................................................................................ 41
2.3.3 Polymer based gels ................................................................................................. 42
2.3.4 Perma-GelTM ........................................................................................................... 43
2.3.5 Summary ................................................................................................................. 44
2.4 Body Armour ................................................................................................................. 47
2.4.1 History..................................................................................................................... 47
2.4.2 Forms of body armour ............................................................................................ 48
2.4.2.1 Soft body armour ............................................................................................. 48
2.4.2.1.1 Para-aramids ............................................................................................. 49
2.4.2.1.2 UHMWPE ................................................................................................. 50
2.4.2.1.3 Polyamides ................................................................................................ 51
2.4.3 How does body armour work? ................................................................................ 51
2.4.4 Body armour failure mechanisms ........................................................................... 53
2.4.5 UK Police soft body armour ................................................................................... 54
2.4.7 Summary ................................................................................................................. 56
2.5 Review of previous overmatching armour investigations ............................................. 57
2.5.1 The shielding capacity of the standard military flak jacket against ballistic injury to
the kidney (O’Connell et al., 1988) ................................................................................. 57
2.5.2 The personal protective equipment provided for combatants: The part played by
wearing a protection vest in the behaviour of projectiles. Wounding outcomes (Breteau
et al., 1989) ...................................................................................................................... 58
2.5.3 Small Arms vs Soft Armour (Prather, 1994) .......................................................... 59
2.5.4 Study on the wound ballistics of fragmentation protective vests following
penetration by handgun and assault rifle bullets (Missliwetz et al., 1995)...................... 62
2.5.5 The destabilising effect of body armour on military rifle bullets (Knudsen and
Sørensen, 1997)................................................................................................................ 65
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2.5.6 Is the wounding potential of high velocity military bullets increased after
perforation of textile body armour? (Lanthier, 2003; Lanthier et al., 2004) ................... 66
2.5.7 Miscellaneous ......................................................................................................... 67
2.5.8 Case studies ............................................................................................................. 68
2.5.9 Summary ................................................................................................................. 70
2.6 Overall summary of literature review ............................................................................ 71
Chapter 3 : EXPERIMENTAL SELECTION AND JUSTIFICATION OF A TISSUE
SIMULANT ............................................................................................................................. 72
3.1 Introduction .................................................................................................................... 72
3.2 Part A – Depth of penetration of 5.5mm ball bearings .................................................. 72
3.2.1 Materials and methods ............................................................................................ 73
3.2.1.1 Simulants.......................................................................................................... 73
3.2.1.1.1 Gelatine ..................................................................................................... 73
3.2.1.1.2 Perma-GelTM ............................................................................................. 74
3.2.1.2 Ball bearings .................................................................................................... 76
3.2.1.3 Depth of penetration testing method ................................................................ 76
3.2.1.4 Depth of penetration analysis........................................................................... 79
3.2.2 Results ..................................................................................................................... 80
3.2.2.1 Depth of penetration results for 5.5mm BBs in 10% gelatine, 20% gelatine and
Perma-GelTM ................................................................................................................ 85
3.2.2.2 Depth of penetration results for 5.5mm BBs in 10% and 20% gelatine .......... 87
3.2.2.3 Depth of penetration results for 5.5mm BBs in re-melted Perma-GelTM ........ 88
3.2.3 Discussion of depth of penetration testing .............................................................. 88
3.3 Part B – Baseline simulant tests ..................................................................................... 92
3.3.1 Materials and methods ............................................................................................ 92
3.3.1.1 Simulants.......................................................................................................... 92
3.3.1.2 Ammunition ..................................................................................................... 92
3.3.1.3 Baseline simulant method ................................................................................ 94
3.3.1.4 Baseline simulants analysis.............................................................................. 95
3.3.1.4.1 High speed video analysis ......................................................................... 99
3.3.2 Results ................................................................................................................... 100
3.3.2.1 Projectile construction ................................................................................... 100
3.3.2.2 .223 Remington Federal Premium® Tactical® Bonded® results ................. 103
3.3.2.2.1 ANOVA results ....................................................................................... 106
3.3.2.3 9 x 9mm FMJ results...................................................................................... 110
3.3.2.3.1 ANOVA results ....................................................................................... 114
3.3.3 Discussion of baseline simulant tests .................................................................... 118
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3.3.3.1 Baseline tests with .223 Remington Federal Premium® Tactical® Bonded®
projectiles ................................................................................................................... 118
3.3.3.2 Baseline tests with 9mm Luger projectiles .................................................... 119
3.3.3.3 Overview of baseline tests ............................................................................. 120
3.4 Part C – Ballistic testing of porcine samples ............................................................... 122
3.4.1 Materials and methods .......................................................................................... 122
3.4.1.1 Target materials ............................................................................................. 122
3.4.1.1.1 Porcine samples ...................................................................................... 122
3.4.1.1.2 Gelatine ................................................................................................... 123
3.4.1.2 Ammunition ................................................................................................... 123
3.4.1.3 Ballistic testing method.................................................................................. 124
3.5.1.4 Analysis.......................................................................................................... 126
3.5.1.4.1 Comparison of results from porcine and baseline testing ....................... 129
3.4.2 Results ................................................................................................................... 130
3.4.2.1 .223 Remington Federal Premium® Tactical® Bonded® results ................. 130
3.4.2.1.1 Distance to projectiles ANOVA ............................................................. 133
3.4.2.1.2 Distance to .223 Remington Federal Premium® Tactical® Bonded®
projectiles (non-rib striking shots removed) ANOVA ........................................... 134
3.4.2.2 9 x 9mm FMJ results...................................................................................... 135
3.4.3 Discussion ............................................................................................................. 136
3.5 Discussion on the selection and justification of a tissue simulant ............................... 138
3.5.1 Perma-GelTM ......................................................................................................... 138
3.5.2 Gelatine ................................................................................................................. 138
3.6 Chapter summary ......................................................................................................... 140
Chapter 4 : THE OVERMATCHING OF ARMOUR ........................................................... 141
4.1 Introduction .................................................................................................................. 141
4.2 Part A: Armoured gelatine blocks 500mm in length ................................................... 141
4.2.1 Materials and methods .......................................................................................... 141
4.2.1.1 10% gelatine................................................................................................... 141
4.2.1.2 Body armour .................................................................................................. 142
4.2.1.3 Ammunition ................................................................................................... 143
4.2.1.4 Ballistic testing method.................................................................................. 143
4.2.1.5 Analysis.......................................................................................................... 144
4.3.1.6 EKE deposited and high speed video analysis ............................................... 144
4.2.2 Results from .223 Remington Federal Premium® Tactical® Bonded® rounds .. 145
4.2.2.1 ANOVA results .............................................................................................. 152
4.2.2.1.1 Neck length ............................................................................................. 152
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