ADVANCED COMPOSITE MATERIALS & TECHNOLOGIES FOR DEFENCE

By 1)SUNIL RATHOD MM15M12 2)MANGESH SHINDE MM15MO8 3)MAYUR CHAVAN MM15M11

COMPOSITES FOR ARMOURo Noval ceramic materials, composite materials and

steels- highlighted in the recent Defence Technology Strategy - that address these issues.

o Novel materials approaches to improve the resistance of materials to high rate mechanical loading, wear and impact.

o Modelling of the response of materials to high rate loading, including high rate materials property development for the input to such models.

o Predicting and improving the high rate deformation performance of polymer composite materials and structures.

oSince energy absorption in composite primarily occurs due to elongation and failure of fiber, fiber with high tensile strength and high strain to failue are best candidates.oIn addition high sonic velocity in the fibre (depends upon Elastic Modulus &Density) can lead to enhanced ballistic performance due to its ability to spread out energy to larger areas.o A Ballistic figure of merit U for ballistic applications has been

proposed where

COMPOSITES‐ FIBERS FORBALLISTIC ARMOUR

Future armour

Presently in Use

o Kevlar (Aramid fiber), S 2 Glass & Dyneema (UHMPE) are already in use for ballistic applications

o Future armour may useM5 fiber (PIPD) & SWCNT (single wall carbon nano tube) fibers

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COMPOSITES‐RESINS FOR BALLISTIC ARMOURoCompatible with fibers Good ‐ Wetability

oModerate interface strength should ‐ allow de lamination and fiber ‐deformation

oHigh elongation to allow fibers to stretch to their limits

oFire and Water Resistance

oBoth thermo set and thermoplastic resins are being used

Thermosets Phenolics, Epoxies Thermoplastics

o ‐Polypropylene(PP), Styrene isoprene styrene(SIS), ‐ ‐ Polyethylene (PE)

oHowever, as compared to fiber, effect of resin matrix is only marginal11

DESIGN OF COMPOSITE ARMOUR FOR SOFT PROJECTILES(SMC, AK 47 &‐ SLR)Core material in soft projectile: Lead antimony or mild steel

• Striking velocity: 390 – 830 m/s at 10 m distance

• Impact energy: 1000 J 3500‐ J

• Typical applications: BPJ, Helmet and VIP Vehicles

Material choice:• Glass composites• Aramid composites• UHMWPE

composites

Decrease in weight

Increase in Cost

7.62 Lead & MS, 9mm Lead Projectiles

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ARMOUR Role of armour is protect a person , device or structure.

Achieved by absorbing kinetic energy of projectile.

Energy may dominantly be absorbed by plastic deformation and/or fracture processes.

Fragments as a result of fracture process should not cause damage to what is being protected and should be arrested by another layer at the back.

Armour plate may have to fulfill two roles: a protective role and structural role

Both roles can be fulfilled by having sufficient strength at high strain rate and appropriate thickness to provide both protection and structural requirements of the Platform.

oProtection requirements are threat drivenoVery significant analysis is done to identify

threat probability and threat development under different scenario.

oHowever, threats may be considered to be of some basic fundamental types

oImpact: Kinetic Energy, Chemical Energy (“Shaped Charge”)

oBlast:o Mines (AP, AT, Influence), HESHoCombined blast and impactoSpecific weapons, entrained debris (Claymore mines)

• ‐

TECHNICAL REQUIREMENTS

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Anti Tank Guided Munitions

Smart Artillery

Unguided Artillery

Bomblets

Unguided / Guided Mortars Terminally Guided

Sub Munition

Platform Threats

Mines

Rocket Propelled Grenades

Tank kinetic energyGuns

Tank chemical energy

Directed Energy Weapons

Chemical hazard

Radiological and nuclear hazard

Improvised Biohazard

ExplosiveDevices

SOME THREATS

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oDesirability of composite solutions for armour‐ better mobility and transportabilityoAbility of material to provide resistance to impact depends upon

‐Hardness to blunt projectile‐High strain to failure to absorb energy via a global deformation process involving brittle fracture in ceramics and composites or plastic deformation in metals.

oComposites rely primarily on brittle micro fracture events to absorb energy. Ultimate energy absorption is largely controlled by strain to failure of fibers.

oComposites are soft and are not effective against hard projectiles However, when coupled with ceramics as laminates, they provide effective solution

WHY COMPOSITES

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BODY ARMOUR: PROBLEMS AND REQUIREMENTS

• Lightweight (now the body armour is 13 kg)

• Flexible wear and allowing mobility • Low cost

• Stop projectile penetration

• Diffuse the impact energy to reduce behind armour blunt trauma (BABT)

How it works

Hybrid Sandwich Structure

Outer layer: a laminate composite structure to diffuse the energy of the impact and to resist to deeper penetrations

Armour substrate

Inner layer: auxetic foam structure acting as small airbags to protect the body from BABT

SCHEMATIC STRUCTURE

1mm

5 mm

10 mm

THE OUTER HIERARCHICAL COATING

• It is well-known that biological materials present optimized structure and excellent mechanical properties.

• The challenge is to deposit a hierarchical hard and tough ceramic-metal multilayered coating that mimics nature (e.g. nacre (mother of pearl), mollusc shell and ancient fish armour).

• The initial coatings have been deposited by CVD (W3C and B13C2) and PVD (Ti-V-Zr and Ti-V-Zr nitride):

• CVD is a high temperature process (1000ºC for B13C2) and therefore just few substrate are compatible.

• PVD coatings can be deposited on CVD films but the opposite is not always true – e.g. we experienced decomposition of the PVD films in the atmosphere needed for CVD deposition.

NACRE (MOTHER OF PEARL)

• Nacre is a ceramic laminate composite made of aragonite tablet layers separated by thin layers of an organic material (polymer).

• Nacre resists impact by dissipating the impact energy through nano and micron cracks, plastic deformation and elastic responses.

Barthelat, et al. Experimental Mechanics 2007Materials Research to Meet 21st Century Defence Needs, 2003.

ANCIENT FISH ARMOUR

Each layer had a specific deformation and energy dissipation mechanism: •The stiff outer layer transferred the energy of an applied load to the layers below•The stratified isopedine layer hinders deeper penetrations and prevents catastrophic cracking through micro-cracking in the sub-layers.

Bruet et al. Nature Materials, 2008.

Young modulus and hardness increase (inside to outside of the armour)

IMPROVED BALLISTIC PERFORMANCE OF COATED PLATES

•The ballistic performance against a high velocity (> 350 m/s) impact 9 mm bullet of aluminium alloy plates with and without 0.762 mm thick cobalt-molybdenum-chromium or Zirconia plasma spray coatings. • Penetration depth on the front face of the plate and the bulging on the rear face of the plate were compared for plates with and without coatings.

• The coatings improved the ballistic resistance of the plates with an increase in non-perforating projectile velocity and a decrease in penetration depth and bulging.

AUXETIC MATERIALS – WHAT ARE THEY ? Conventional materials have a positive Poisson’s ratio

Auxetic materials have a negative Poisson’s ratio - grow fatter when stretched

.

Poisson’s Ratio = _ Change in X Change in Y

AUXETIC MATERIALS - BACKGROUND Auxetic materials have been known for approximately

100 years

Field only started to be studied in 1987 by Rod Lakes

The term auxetic was coined by Ken Evans - derived from the Greek word auxetikos which means ‘that tends to increase’

Surge in interest since the late 1980’s

Conventional Foam Auxetic Foam

x5 x5

Alicona InfiniteFocus optical 3D measurement device

Scanning Electron Microscopy (SEM)

AUXETIC MATERIALS – IMPORTANCE TO THE HIGH STRAIN PROJECT

Auxetic foam to act as ‘smart airbags’

Act behind sandwich structure

Auxetic materials are popular for their increase in impact resistance and energy absorption:

- Reduce BABT - Reduce / prevent backface signature injury

Non-auxetic

Auxetic

FUTURISTIC MATERIALS‐ LET US AIM BIGThis tiny block of

transparent Aerogel is supporting a brick

density2.5 kg. The

is

0.1

weighing aerogel's g/cm3.

Carbon nanotubeshave numerous remarkable physical properties including the strongest sp2 bond, even stronger than the sp3 bonds that hold together diamond

Fullerenescan be

substantially than diamond, greater energy

made stronger but for cost

23/11

Advanced Technology Development

Behind Armor EffectsMethodology

Casualty ReductionAnalysis Model

• New high performance polymers/ fibers/composites• Nanotechnology• Advanced ceramics & metals• Enhanced predictive modeling• Material systems integration

0.0

0.2

0.4

0.6

0.8

1.0

50 150 250 350 450 550 650 750Acceleration (g's)

Prob

abili

ty o

f Inj

ury Example Risk

Function50% Injury Risk at 270 g(p = 0.05)

Conduct experimental (tissue & test fixture), analytical and numerical assessments of non-penetrating impact on body armor/body

Develop/update models for armor system performance from threat definition to incapacitation effect

Key Focus Areasfor Research and Development

THANK YOU

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REFERENCES Army focused research team on functionally gradedarmor

composites Ernest S.C. Chin

Defence Innovation in India The Fault Lines, Laxman Kumar Behera,Institute for Defence Studies and Analyses, New Delhi.

o J P Agrawal Scientist Explosives Research & Development Laboratory Pune Scientific Information 8r Documentation Centre (DESIDOC) Defence Research & Development Organisation Ministry of Defence, Delhi-110 OM

o “Advances in healing on demands polymer and polymer composites”,Pengfei Zhang,Guoqiang Li

Composites used in aero defence.