Materials for Soft and

Materials for Soft and
Hard Armor Systems

Dr. Ronald G. Kander

Professor & Department Head

Integrated Science & Technology

The Washington Post
–


Baghdad, December 4, 2003

“Private First Class Gregory Stovall felt the explosion on his face. He was
standing in the turret of a Humvee, manning a machine gun, when the
roadside bomb went off. At the time, he was guarding a convoy of trucks
making a mail run. In an instant, Stovall’s face was perforated by shrapnel,
the index finger on his right hand was gone, and the

middle finger was hanging by a tendon. But the

22
-
year
-
old from Brooklyn remembers instinctively

reaching for his chest and stomach
—

“to make sure

everything was there,” he said. It was, encased in a

Kevlar vest reinforced by boron carbide ceramic

plates that are so hard they can stop AK
-
47 rounds

traveling 2,750 feet per second. Thus, on the morning

of November 4, Stovall became the latest in a long line

of soldiers serving in Iraq to be saved by the U.S.

military’s new Interceptor body armor.”

Presentation Outline


Background


Types of Systems


Materials/Mechanisms


Summary


•

Armor Systems in FCS Program

•

Materials in Armor Systems

•

Passive Systems

•

Soft Armor

•

Hard Armor

•

Reactive Systems

•

Explosive

•

Electromagnetic

•

Novel Concepts

•

Biomimetics

•

Nanomaterials

•

Material Selection & Design

•

Energy Absorption Mechanisms

•

Advantages/Disadvantages

•

Mobility/Reliability/Survivability

FCS Survivability Strategy

Detected

–

Signature Reduction

Acquired

–

Obscurants & Jammers

Hit

–

Decoys & Active Protection

Penetrated

–

Passive & Reactive Armor Systems

Killed

–

Spall Reduction & Fire Suppression

Don’t be
:

Armor Systems in FCS Program


“Because of the extraordinary
lethality of modern weapon
systems, many regard soldier
survivability as the most significant
challenge for the Future Combat
Systems Program.”


“Furthermore, weight, mobility, and
fuel consumption constraints no
longer allow designers to improve
protection by simply inserting more
traditional, heavier armor between
the soldier and the projectile.”

Colonel Brian R. Zahn, “The Future Combat System: Minimizing Risk While
Maximizing Capability”, USAWC Strategy Research Project, April 24, 2000.

The Weight Problem


The M1 Battle Tank (~70 tons)


The Bradley Fighting Vehicle (~35 tons)


Neither can be deployed on a C
-
130 (~20 tons)


Both rely on the C
-
5, C
-
17, or sealift for transport

0
10
20
30
40
50
60
70
80
90
100
1940
1950
1960
1970
1980
1990
2000
2010
2020
Year
Weight (tons)
M48
M60
M60A1
M60A2
M60A3
M1
M1A1
M1A2
M1A2(SEP)
The FCS Challenge

FCS

LTC Marion H. Van Fosson, “Briefing on the Future Combat Vehicle”, PM Future Combat Vehicle, Oct. 6, 1999.

Armor Systems Challenge

Mobility

Reliability

Survivability

Materials Selection

and Design

Light Weight

Robust

High

Performance

Types of Armor Systems


Passive Systems


soft armor


hard armor


Reactive Systems


explosive


electromagnetic


Novel Concepts


biomimetics


nanomaterials

Materials

Selection

Design

Parameters

Energy

Absorption

Mechanisms

Passive Systems


Soft Armor


aramid (Kevlar
®
)


polyethylene (Spectra
®
)


fiberglass (S
-
2)


polyester, nylon, etc.


Hard Armor


ceramics


metals


composites


Hybrid Systems

Soft Armor Systems

Fiber

Composition

Arial

Density

System

Design

Fiber

Denier

Fabric

Weave

Soft Armor Systems:

Damage Accumulation Mechanism

www.nist.gov/public_affairs/ licweb/speeding.htm


Hard Armor Systems

Ceramics

Metals

Polymers

Composites

Hard Armor Systems

“Materials Research to Meet 21
st

Century Defense Needs”, National

Research Council, National Academies Press, Washington DC, 2004.

Hard Armor Systems:

Damage Accumulation Mechanism

Energy Absorbed (J)

E S V
 
Specific Energy Absorption (J/m
3
)

Damaged Volume (m
3
)

Hard Armor Systems:

Damage Accumulation Mechanism


Crack Initiation


Crack Propagation


Crack Deflection


Phase Transformation


Fiber Breakage


Fiber Pull
-
Out


Bond Breakage


Cavitation

Viscoelastic Response

www.firstdefense.com/ html/default_faqs.htm


Transparent Armor Systems


Aluminum Oxynitride (AlON)


Magnesium Aluminate (spinel)


Aluminum Oxide (sapphire)


Glass/Polycarbonate Laminates

www.firstdefense.com/ html/default_faqs.htm


Passive Systems:

Improvement Potential

“Materials Research to Meet 21
st

Century Defense Needs”, National

Research Council, National Academies Press, Washington DC, 2004.

Passive Systems:

Improvement Potential

“Materials Research to Meet 21
st

Century Defense Needs”, National

Research Council, National Academies Press, Washington DC, 2004.

Reactive Systems


Explosive


sandwich construction


explosive core


oblique impact


disrupts penetration


Electromagnetic


sandwich construction


charged plates w/air gap


magnetic field generated


magneto hydrodynamics

Reactive Systems


Explosive Armor


Developed in the late 1970’s


Implemented in the early 1980’s


US implementation in the mid 1980’s


Impressive mass efficiency


Less effective against high
-
velocity threats
and on lightly armored vehicles


Less robust vs. passive systems

Reactive Systems


Electromagnetic Armor


Envisioned in the late 1970’s


Unclassified research through the 1990’s


Electrothermal Armor


Similar in concept to EM armor


Thin insulating core (vs. large air gap)


Explosive expansion (like explosive armor)


Large power requirements using existing technology

Novel Armor Concepts


Soft/Hard Hybrid Systems


elastomeric composites



Biomimetic Systems


nanostructured materials


“Materials Research to Meet 21
st

Century Defense Needs”, National

Research Council, National Academies Press, Washington DC, 2004.

Biomimetic Nanostructures

Biology

Materials

Science


Nanostructures

Design of Bioinspired

Structural Materials

Biomimetic Nanostructures

“Materials Research to Meet 21
st

Century Defense Needs”, National

Research Council, National Academies Press, Washington DC, 2004.

“Materials like bone, teeth, and shells are
simultaneously hard, strong, and tough and have
unique hierarchical structural motifs originating at
the nanometer scale. Mimicking such designs
should lead to very strong, tough materials usable
in lightweight armor for both warfighters and
vehicles. It could also be used for mechanical
system components.”

Spicule: Sponge Fiber

Mehmet Sarikaya, et. al, “Biomimetics: Nanomechanical Design of Materials Through Biology”, 15th
ASCE Engineering Mechanics Conference, Columbia University, June 2002.

Nacre: Mother
-
of
-
Pearl

Mehmet Sarikaya, et. al, “Biomimetics: Nanomechanical Design of Materials Through Biology”, 15th
ASCE Engineering Mechanics Conference, Columbia University, June 2002.

“Materials Research to Meet 21
st

Century Defense Needs”, National

Research Council, National Academies Press, Washington DC, 2004.

Functionally Gradient Materials

Mehmet Sarikaya, et. al, “Biomimetics: Nanomechanical Design of Materials Through Biology”, 15th
ASCE Engineering Mechanics Conference, Columbia University, June 2002.

High Performance Fibers


Spider Silk


Researchers have recently
been able to splice the
genes for spider silk into
cells from a variety of other
organisms that, when
grown in tissue culture,
produce material that can
be spun into silk threads.


The group plans to transfer
the genes to goats that
have been bred to produce
the silk in their milk.

“Materials Research to Meet 21
st

Century Defense Needs”, National

Research Council, National Academies Press, Washington DC, 2004.

Nanostructured Materials

“Today, nanomaterials are barely more than a
laboratory curiosity. Usually, only small quantities of
material can be produced, and production is
generally measured in hours or days. If
nanomaterials are to become widely applied, it will
be essential to address the challenge of scaling up
their production to macroscopic quantities while
retaining the performance properties of the small
samples currently available.”

“Materials Research to Meet 21
st

Century Defense Needs”, National

Research Council, National Academies Press, Washington DC, 2004.

Modeling & Simulation

Real World

Problem

Real

Model

Mathematical

Model

Conclusions

© Daniel Maki & Maynard Thompson; Indiana University

Computer

Model

Simplify

Abstract

Calculate

Interpret

Program

Simulate

Advantages

Save

Testing

Save

Money

Save

Time

Modeling

&

Simulation

Steel vs. Hybrid Armor Simulation

Dale S. Preece & Vanessa S. Berg, “Bullet Impact on Steel and Kevlar®/Steel Armor
-

Computer
Modeling and Experimental Data”, Sandia National Laboratories, ASME Pressure Vessels and Piping
Conference Symposium on Structures Under Extreme Loading, San Diego, July 2004.

Steel Results

Dale S. Preece & Vanessa S. Berg, “Bullet Impact on Steel and Kevlar®/Steel Armor
-

Computer
Modeling and Experimental Data”, Sandia National Laboratories, ASME Pressure Vessels and Piping
Conference Symposium on Structures Under Extreme Loading, San Diego, July 2004.

Hybrid Results

Hybrid Results

Dale S. Preece & Vanessa S. Berg, “Bullet Impact on Steel and Kevlar®/Steel Armor
-

Computer
Modeling and Experimental Data”, Sandia National Laboratories, ASME Pressure Vessels and Piping
Conference Symposium on Structures Under Extreme Loading, San Diego, July 2004.

Summary of Presentation

Mobility

Reliability

Survivability

Materials Selection

and Design

Light Weight

Robust

High

Performance

Summary of Presentation


Passive Systems


soft armor


hard armor


Reactive Systems


explosive


electromagnetic


Novel Concepts


biomimetics


nanomaterials


Modeling & Simulation

Materials

Selection

Design

Parameters

Energy

Absorption

Mechanisms

What does the future hold?

“Computers in the future may


weigh no more than 1.5 tons.”


—

Popular Mechanics, 1949