Establishing design characteristics for the development of stab resistant Laser Sintered body armour

271 Pages·2017·16.79 MB·English

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Establishing design
characteristics for the
development of stab resistant
Laser Sintered body armour
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Additional Information:
• A Doctoral Thesis. Submitted in partial fulfilment of the requirements
for the award of Doctor of Philosophy of Loughborough University.
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Please cite the published version.
Loughborough Design School
Advanced Additive Manufacturing Group – University of Sheffield

Establishing design characteristics for the development of stab
resistant Laser Sintered body armour

By
Andrew Allan Johnson

Doctoral Thesis Submitted in partial fulfilment of the requirements
for the award of
Doctor of Philosophy of Loughborough University

November 2014
© Andrew Allan Johnson, 2014
Abstract
Abstract
Stab resistant body armour had been used throughout history, with examples ranging from
animal hide construction to the moulded Polycarbonate units typically used by United Kingdom
(UK) Police Officers. Such protective articles have historically, and continue to present a number
of issues which have shown to impair the operational performance of its wearer – including but
not exclusive to poor thermal regulation, large masses, and reduced manoeuvrability.

A number of developments have been made in an attempt to minimise the effects of such issues.
One potential solution yet to be fully explored is the utilisation of Additive Manufacturing (AM)
technologies. In recent years the use of such manufacturing technologies, particularly Laser
Sintering, has successfully demonstrated their suitability for a range of high performance
applications ranging from Formula 1® to aerospace. Due to the fundamental additive nature of
AM build processes, the utilisation of such technologies have facilitated the realisation of design
concepts that are typically too expensive, difficult or impossible to create using traditional
manufacturing processes. In order for AM technologies to be used for the generation of stab
resistant body armour a number of historical issues and performance characteristics fundamental
to ensure stab resistance is achieved must be satisfied.

This body of research firstly evaluated the stab resistive performance of two of the most common
materials suitable for Laser Sintering – as highlighted by an initial review of AM technologies.
Once an appropriate material had been highlighted it was used as the basis for further
experimental testing. Such tests focussed on minimising the material thickness required to
maintain an appropriate level of stab resistance within United Kingdom Home Office Scientific
Development Branch (HOSDB) KR1-E1 requirement of 24 Joules of stab impact energy. Test
results demonstrated that specimens manufactured from Duraform EX® required a minimum
single layer thickness of 11.00 mm, and a dual layer total thickness of 9.00 mm to provide an
appropriate level of stab protection within the HOSDB KR1-E1 standard.

Coupled with the results generated from an investigation identifying the overlapping/imbricated
assembly angle required to maintain an appropriate level of coverage across a scale structure, the
stab resistant characteristics initially identified were used for the development of an imbricated
scale-like assembly. Additional design features were also investigated to further minimise the
total thickness of the final element design and corresponding assembled imbricated structure –
ii
Abstract
such features included angling strike surfaces and integrating a dual layered structure within
individual elements.

When the finalised imbricated assemblies were stab tested, they successfully demonstrated levels
of stab resistance to the UK HOSDB KR1-E1 impact energy of 24 Joules.

iii
Acknowledgements
Acknowledgements

To the supervisory dream team - many thanks for your guidance during this research. Thank you
for pushing me. I owe you both so much.

Dr. Guy Bingham and Dr. Candice Majewski

A personal thanks to Guy for introducing me to the field of AM, holding doors open for me, for
seeing my potential, and for being a good friend.

Dr. Guy Bingham

I would like to express my gratitude to Russ and his colleagues within the AMRG for allowing me
significant access to their facilities and wealth of expertise.

Professor Russ Harris & Loughborough University
Additive Manufacturing Research Group

Thank you to Ben and his colleagues within Loughborough University's Sports Technology
Institute for allowing me access to various pieces of test apparatus.

Dr. Ben Halkon & Loughborough University Sports Technology Institute

I would like to express my appreciation to my friends and colleagues within the L.D.S. for creating
an enjoyable environment to conduct research. I would also like to thank Loughborough Design
School for their financial support during this research.

Friends, Colleagues & Loughborough Design School

I wish to thank my examiners for their time and input during the examination process.
Dr. Allan Rennie (Lancaster) & Dr. Richard Bibb (Loughborough)

Thank you to my family for their support throughout all of my studies.
Family

Finally I would like to thank Dr. Carolyn Plateau - you are incredible!
A great journey has been made all the sweeter for finding you.
Carolyn Plateau

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Publications & Awards
Publications & Awards

Refereed Journal Publications

A. Johnson, G.A. Bingham, D. Wimpenny, “Additive manufactured textiles for high-performance
stab resistant applications”, Rapid Prototyping Journal, Vol. 19, Issue 3, pp. 199-207, 2013.

‘Highly Commended Paper of 2013’ - Awarded by the ‘Rapid Prototyping Journal’
Editorial Team, March 2014.

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Refereed Conference Publications

G.A. Bingham, A.M. Paterson, R.J. Bibb, A. Johnson, “Additive Manufactured Textiles: Design,
Modelling and Applications”, Advances in Functional Textiles - 25-26th July 2013, Manchester.

G.A. Bingham, R.J. Bibb, A.M. Paterson, A. Johnson, “The Design and Modelling of Additive
Manufactured Textile Structures and Garments”, 1st International Conference on Digital Fashion -
16-18th May 2013, London.

A. Johnson, G.A. Bingham, C.E. Majewski, “Establishing the performance requirements for stab
resistant Additive Manufactured Body Armour (AMBA)”, 23rd Annual International Solid Freeform
Fabrication Symposium - An Additive Manufacturing Conference - Austin, Texas, pp. 297-306,
2012.

A. Johnson, G.A. Bingham, C.E. Majewski, “AMBA - Additive Manufactured Body Armour”, 23rd
Annual International Solid Freeform Fabrication Symposium; An Additive Manufacturing
Conference - 6th-8th August 2012 Austin, Texas.

‘Best Research Poster’ - Awarded by Emerald Publishing at the 23rd Annual International
Solid Freeform Fabrication Symposium (SFF) in Austin Texas. Poster entitled, ‘Generating
Additive Manufactured Body Armour for Real-World Threats’ (2012).

A. Johnson, G.A. Bingham, C.E. Majewski, “Utilising Additive Manufacturing technology for the
development of knife resistant soft body armour to UK performance requirements”, IOM3
Advances in Protective Clothing Conference - 25th April 2012, Farnborough.
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Publications & Awards

‘Best Research Poster’ – £500 award sponsored by the IOM3 and the UK Defence Science
& Technology Laboratory (DSTL) at the 2012 Advances in Protective Clothing Conference.
Poster entitled ‘AMBA – Additive Manufactured Body Armour’.

A. Johnson, G.A. Bingham, C.E. Majewski, “Additive Manufactured Textiles for High-Performance
Stab Resistant Application”, Proceedings of the 12th Conference on Rapid Design, Prototyping and
Manufacturing (RDPM), Lancaster, pp. 87-96, 2011.

‘Best Written Student Paper’ – Awarded £100 by HK Technologies at the 12th Conference
on Rapid Design, Prototyping & Manufacturing (RDPM). Paper entitled, ‘Additive
Manufactured Textiles for High-Performance Stab Resistant Applications’ (2011).

A. Johnson, G.A. Bingham, C.E. Majewski, “AMBA - Utilising Additive Manufacturing for the
development of knife resistant body armour to UK requirements”, Loughborough Research
Conference; Research that Matters - 6th March 2012, Loughborough.

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Additional Awards

The Sir Robert Martin Achievement Prize - £1000 award for an outstanding combination of
academic and non-academic achievement. Awarded by Loughborough University, May 2014.

‘Best Research Presentation’. Loughborough Design School Research Student Conference
(DeSRes), Loughborough University (2013). Presentation entitled: ‘AMBA – 3D Printed Stab
Resistant Body Armour’.

Loughborough University Development Trust Award - £300 award contribution to attend the
Solid Freeform Fabrication Symposium in Austin, Texas, in August 2012 (Received January 2012).

Ph.D. Studentship sponsored by Loughborough Design School, Loughborough University.
Funding to support Ph.D. research relating to the development of Additive Manufactured stab
resistant body armour (April 2011).

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Table of Contents
Table of Contents
Abstract .............................................................................................................................................. ii
Acknowledgements ........................................................................................................................... iv
Publications & Awards ....................................................................................................................... v
Table of Contents ............................................................................................................................. vii
Nomenclature ................................................................................................................................. xiii
List of Figures ...................................................................................................................................xvi
List of Tables .................................................................................................................................... xxii
List of Equations ............................................................................................................................. xxiii
Chapter 1 Introduction.................................................................................................................... 1
1.1 Background......................................................................................................................... 1
1.2 Research Aim ...................................................................................................................... 2
1.3 Objectives ........................................................................................................................... 3
1.4 Thesis Structure .................................................................................................................. 3
Chapter 2 Sharp-Force Incidents ..................................................................................................... 6
2.1 Introduction ....................................................................................................................... 6
2.2 Weapon Type & Geometry ................................................................................................ 7
2.3 Stab Force Principles and Kinematics ................................................................................. 9
2.4 Injury Location .................................................................................................................. 10
2.5 Blunt-Force Incidents ....................................................................................................... 13
2.6 Protective Solutions ......................................................................................................... 16
2.7 Legislation and Standards ................................................................................................ 16
2.7.1 Knife and Spike Resistance ....................................................................................... 17
2.7.2 Additional Mechanical Testing ................................................................................. 21
2.8 Research Implications ...................................................................................................... 22
2.9 Summary .......................................................................................................................... 22
Chapter 3 Armour ......................................................................................................................... 24
3.1 Introduction ..................................................................................................................... 24
3.2 Biological Scale Armour .................................................................................................... 25
3.2.1 Placoid Scales ........................................................................................................... 26
3.2.2 Ganoid Scales ........................................................................................................... 27
3.2.3 Osteoderms .............................................................................................................. 29
3.2.4 Elasmoid Scales ........................................................................................................ 30
3.2.5 The Pangolin ............................................................................................................. 32
3.2.6 Scale Design .............................................................................................................. 33
vii
Table of Contents
3.2.7 Summary .................................................................................................................. 37
3.3 Historical Armour ............................................................................................................. 38
3.3.1 Greek Armour: 1000 BC to 400 BC ........................................................................... 38
3.3.2 Roman Armour: 753 BC to AD 476 ........................................................................... 39
3.3.3 Chainmail Armour .................................................................................................... 41
3.3.4 Historical Armour Summary ..................................................................................... 44
3.4 Modern Body Armour ...................................................................................................... 44
3.4.1 Physiological Effects ................................................................................................. 49
3.4.2 Modern Body Armour Summary .............................................................................. 51
3.5 Next-Generation Body Armour Research ........................................................................ 51
3.5.1 Carbon Nanotubes ................................................................................................... 51
3.5.2 Liquid Armour ........................................................................................................... 53
3.5.3 Inspired by Nature .................................................................................................... 55
3.5.4 Next Generation Armour Summary ......................................................................... 56
3.6 Patent Review .................................................................................................................. 57
3.6.1 Fibre-based Solutions ............................................................................................... 57
3.6.2 Rigid Armour ............................................................................................................ 59
3.6.3 Articulated Armour .................................................................................................. 63
3.6.4 Additional Notable Patents ...................................................................................... 67
3.6.5 Patent Review Summary .......................................................................................... 68
3.7 Summary .......................................................................................................................... 68
Chapter 4 Additive Manufacturing ............................................................................................... 70
4.1 Introduction ..................................................................................................................... 70
4.1.1 Advantages ............................................................................................................... 72
4.1.2 Limitations ................................................................................................................ 73
4.2 AM Manufacturing Technologies ..................................................................................... 73
4.2.1 Stereolithography ..................................................................................................... 73
4.2.2 Fused Deposition Modelling ..................................................................................... 75
4.2.3 3-Dimensional Printing ............................................................................................. 76
4.2.4 Material Jetting ........................................................................................................ 77
4.2.5 Laser Sintering .......................................................................................................... 79
4.2.6 Summary .................................................................................................................. 80
4.3 Additive Manufactured Textiles ....................................................................................... 81
4.3.1 Additive Manufactured Textile Limitations .............................................................. 83
4.3.2 Stab-Resistant Additive Manufactured Textiles ....................................................... 84
4.4 Laser Sintering Materials and Enhancement Processes ................................................... 86
viii
Table of Contents
4.4.1 Layer Resolution ....................................................................................................... 87
4.4.2 Build Orientation and Placement ............................................................................. 88
4.4.3 Energy Density .......................................................................................................... 89
4.4.4 Powder Recycling ..................................................................................................... 89
4.4.5 Post-processing Activities ......................................................................................... 90
4.5 Design Considerations for Polymer Laser Sintering ......................................................... 93
4.5.1 Circular Holes ........................................................................................................... 94
4.5.2 Feature Proximity to Component Edges .................................................................. 95
4.5.3 Minimum Gap and Separation Requirements ......................................................... 95
4.5.4 Further Design Considerations ................................................................................. 96
4.6 Summary .......................................................................................................................... 97
Chapter 5 Research Methodology ................................................................................................ 99
5.1 Problem Definition ........................................................................................................... 99
5.2 Research Aim .................................................................................................................. 100
5.3 Research Approach and Objectives ................................................................................ 101
Chapter 6 Stab Test Experimental Methodology ........................................................................ 102
6.1 Introduction ................................................................................................................... 102
6.2 Instron 9250HV Drop Tower .......................................................................................... 103
6.3 Backing Material ............................................................................................................. 104
6.4 Test and Environmental Requirements .......................................................................... 105
6.5 Recording Blade Penetration ......................................................................................... 107
6.6 Operational Procedure ................................................................................................... 108
6.7 Conclusions .................................................................................................................... 109
Chapter 7 Stab Test Blade Identification .................................................................................... 110
7.1 Introduction ................................................................................................................... 110
7.2 Objectives ....................................................................................................................... 111
7.3 Experimental Methodology ............................................................................................ 111
7.3.1 Stab Test Methodology .......................................................................................... 111
7.3.2 Test Blade ............................................................................................................... 111
7.3.3 Body Armour Test Specimens ................................................................................ 115
7.4 Experimental Design ...................................................................................................... 117
7.5 Results ............................................................................................................................ 118
7.6 Conclusions .................................................................................................................... 120
7.7 Implications for further work ......................................................................................... 121
Chapter 8 Establishing Single Layer Stab Resistance .................................................................. 123
8.1 Introduction ................................................................................................................... 123
ix