1. ARMOR AND MATERIALS FOR COMBAT THREAT AND DAMAGE PROTECTION
Gwynedd A. Thomas, Ph.D.
Auburn University
Polymer and Fiber Engineering

2. Some DoD Projects (Dr. Gwen Thomas, P.I.)
US Army Aviation Applied Technology Directorate (Comanche Project, 1998)
US Army ARDEC Picatinny Arsenal (LOSAT Kinetic Energy Missile Protection, 2001)
US Army Air Warrior Program (Air Warrior Vest Upgrade, Phases 1-3, )
US Navy NAVAIR (V-22 Osprey Internal Armor Provision, current)
Army Research Lab follow-on (2009)
AFSOCOM, AFRL, USSOCOM follow-on (2010 ->)
ONR Roadside Bomb Protection (2010)

3. Modern Military Body Armor
The FLAK jacket
FLAK = Fliegerabwehrkanone (AAA)
This armor was only intended to stop shrapnel
Not intended for bullets

4. Ballistic armor has 2 fields of application
Police and government officials
Rated projectile threats (handguns, long guns)
Armor: light, concealable, flexible
Military applications
Threats from explosive device fragments
High energy projectile threats (smg, rifle, mg)

5. Energy delivered by various ammunitions

6. Modern Protective Materials
Fibers
Very light
Very limited
Very flexible
Ceramics
Very strong
Pretty light
Really expensive!
Metals
Relatively cheap
VERY heavy

7. Energy absorption in aramids
Tensile strength
23-28 gpd
Elongation to break %
Young’s modulus
gpd
Specific gravity = 1.44
Fibrillates on impact

8. Energy absorption in HPPE
Tensile strength
gpd
Elongation to break %
Young’s modulus
gpd
Specific gravity = 0.97
Usually uniaxially wrapped and resin encased*

9. PIPD Fiber
Poly{2,6-diimidazo[4,5-b4',5'-e]pyridinylene-1,4(2,5-dihydroxy)phenylene}
Commercial name “M5”
Reputation as the upcoming Rock Star of ballistic resistant fibers
Tests by U.S. Army Natick Soldier Center labs indicate very promising likelihood of success in ballistic applications
But there is little available right now

10. Ceramics
Aluminum oxide
Silicon Carbide
Boron carbide
Aluminum nitride

11. Aluminum oxide (Al2O3) Also known as alumina
Naturally occurring ore of aluminum
High purity grades make acceptable armor
Spec. grav. =
Less expensive than other armor grade ceramics
Is also the material of rubies and sapphires

12. Silicon carbide (SiC) Very rare in nature
Found in meteorites
Very effective in body armor and
Chobham armor
Much more expensive than alumina
Spec. grav. =
Hardness = 2800 kg/mm2

13. Boron carbide (B4C) Third hardest known material Spec. grav. ~ 2.5
Diamond = 1
Cubic boron nitride = 2
Spec. grav. ~ 2.5
Extremely effective in armor
Very expensive
Hardness = kg/mm2

14. Aluminum Oxynitride (AlON)
“Transparent aluminum” or “transparent ceramic”
Spec. grav. 3.69
Superior to glass and Lexan in transparent armor
Scratch resistant
Defeats .50 cal AP
Very expensive ($10-$15/ square inch!)
Hardness=1850 kg/mm2

15. Fragment defense – nonwoven approach
Strong weight advantages for nonwoven fabrics over woven fabrics (8+lbs)
Initial commercial introduction of 100% HPPE nonwoven - DSM “Fraglight”, 1995
Initial suggestion of blended nonwoven fabrics
Thomas and Thompson, Techtextil 1992
Cordova, Kirkland et al 1994
Nonwovens allow a great deal of moisture and heat transport
compared to tight weaves. This nonwoven does not require
plastic resin coatings.
Fiber blend nonwoven
100% Kevlar nonwoven
(TechTextil Frankfurt, Thomas and Thompson)

16. Energy absorption in HPPE/Aramid fiber blends
Radiated strain energy
Transferred by aramid and HPPE beyond impact area
Fibrillation of aramids
But fabric network integrity preserved by non-malleable character of aramid
Phase change induced in the thermoplastic HPPE
Resulted in a 30% increase in performance over the predicted force dissipation behavior
Tests performed at DuPont labs, Wilmington, DE

17. Fragment armor improvements with nonwoven technology
Results from US Army Aberdeen Proving Grounds test
.22 cal gram, fragment simulating projectile, steel
Parameters :
Weight < 3.42 kg/m2
Projectile speed > 425 m/sec (1400fps)
Nonwoven materials were superior to woven aramid and woven PBO
Historical development of nonwoven armor-
Original Kevlar 29 = 389 m/sec
Original (1991) blend yielded 434 m/sec (HPPE, 2nd quality and Kevlar 29)
* Test results 31 August – 1 September 2002

18. Results of V50 testing, 0.13 gram (2 grain) RCC FSP

19. Results of V50 testing, 0.26 gram (4 grain) RCC FSP

20. Results of V50 testing, 1.0 gram (16 grain) RCC FSP

21. Results of V50 testing, 4.15 gram (64 grain) RCC FSP

22. Results of V50 testing, 9 mm, 8.0 gram (124 grain) FMJ

23. US Marines Test Results I.E.D.’s
2.2lbs/ft2 sample, range 15 meters
Nine fragments impacted the sample panel
No complete penetration.
3 large ( grain) fragments impacted the panel along with six smaller (50 grain or less) fragments.
One of the large fragments, penetrated three ArmorFelt and 14 aramid layers
(out of 3 layers of ArmorFelt, 40 layers of Kevlar, 3 layers of ArmorFelt)
No other large fragments, penetrated deeper than three ArmorFelt layers
None of the fragments completely penetrated the armor.
2 December 2003

24. US Marines Test Results I.E.D.’s (cont)
2.2lbs/ft2 sample, range 5 meters
22 fragments impacted the sample panel
1 complete penetration.
2 large ( grain) fragments impacted the panel along with twenty smaller (50 grain or less) fragments.
Only one of the two large fragments, completely penetrated the armor
(3 layers of ArmorFelt, 40 layers of Kevlar, 3 layers of ArmorFelt)
None of the smaller fragments penetrated the armor.
2 December 2003

25. US Marines Test Results Hand Grenades
Tests performed at Quantico, VA
2 samples tested
A) Identical to Auburn AW design
B) Heavier than Auburn AW design
M-67 hand grenade
One detonation each target from 4 feet range
Results
A) No penetrations on Auburn AW design type
22 hits by fragments
B) 1 penetration on heavier type
17 hits by fragments
November 2003
Test conducted under guidance of Maj. A.J. Butler, USMC (ret)

26. Levels III and IV Very high energy projectiles
7.62 x 51 FMJ (.308)

27. State of the Art SAPI Based on Boron or Silicon Carbide
Small Arms Protective Insert
Based on Boron or Silicon Carbide
Backing made of aramid or HPPE composites

28. ESAPI Enhanced Small Arms Protective Insert
Permits protection against armor penetrating bullets
Was needed protection beginning 2003

29. Ceramic or metal plate armor spall
As the projectile penetrates the armor
fragmentation (shatter) occurs
momentum is transferred to the particles
a spall cloud forms
Vspall =
US Army, ARL Website

30. Armor piercing projectiles
Most serious threat to military personnel with body armor
May use either hardened steel or tungsten carbide
Designed as multicomponent (eg)
copper sheath
lead tip (spall generator)
carbon steel interior
Graphic courtesy of Jeff Simon, SRI International

31. One solution to this problem - Stop the bullets by inducing chaos
A trajectory is a highly ordered kinetic path
Targets are destroyed by release of the kinetic energy where the projectile is aimed
Destabilization can result in degradation of lethality, kinetic energy transfer

32. A flexible hard armor media
Generation of multiple simultaneous paths
Projectile spreads, fragments
Spall cloud redirected by internal geometrics
Fragment defense by nonwovens
Graphic courtesy of Jeff Simon, SRI International
US Patent # 5,736,474, “Multistructure Ballistic Material”, Auburn University
Thomas., 1997

33. Projectile Impact Sequence
How the new armor works:
In the initial stages of the impact, the projectile enters the vest in the normal manner, with standard ballistic resistant fabrics or thin, high strength ceramic plates distorting the leading end and increasing the projectile drag as it enters.
Upon entry into the geometrics zone, the projectile is turned by the deflecting surfaces.
As it continues along the path, the initially turned leading end is deflected into other paths while the trailing end has not yet experienced the torquing action of the shock waves in the projectile body.
The front portion begins to disintegrate, clearing the way for the rear section to be deflected along similar reverse torqued paths until the projectile is finally totally destroyed and comes to rest in the geometric layer.
In initial tests with this media, both 7.62x39 mm Russian and US rifle ammunition have been destroyed at 15 meters distance and less without the use of ceramic front plate facings on the armor package. Both ammunition types were destroyed in multi hit test conditions.

34. ChaoTech: Hard armor media
Generation of multiple simultaneous paths
Projectile spreads, fragments
Spall cloud redirected by internal geometrics
Fragment defense by ArmorFelt
Multiple materials available
ChaoTech reduces the weight of any armor material
7.62x39 API
(6 hits)
APM2
(5 hits)
12.7 mm API
(All projectiles impacted at full muzzle velocities)