Composite armour

The SovietT-64was the first mass-produced tank with composite armour

TheLeclerc tankis equipped withNERA(Non-explosive reactive armour)

Depending on the operating state, theLeopard 2has various extended armour elements such as bomb protection for the top, cage armour, extended mine protection (A6M) or additional armour in the form of composite armourMEXASorAMAP

Plasan SandCatlight (5t) military vehicle featuring integrated composite armoured body

Vehicle add-on armour kit manufactured byComposhield

TheBritish Army'sChallenger 2main battle tankusesChobham armour.

Ceramic-aramid composite laminate armour, ballistic test results

Ceramic tiles for theATF Dingo

SICADURsilicon carbidetiles for vehicles (e.g.Mowag Piranha)

Composite ceramic armor tested in accordance with STANAG 4569 requirements.

Composite armouris a type ofvehicle armourconsisting of layers of different materials such asmetals,plastics,ceramicsorair.Most composite armours are lighter than their all-metal equivalent, but instead occupy a larger volume for the same resistance to penetration. It is possible to design composite armour stronger, lighter and less voluminous than traditional armour, but the cost is often prohibitively high, restricting its use to especially vulnerable parts of a vehicle. Its primary purpose is to help defeathigh-explosive anti-tank(HEAT) projectiles.

HEAT had posed a serious threat to armoured vehicles since its introduction inWorld War II.Lightweight and small, HEAT projectiles could nevertheless penetrate hundreds of millimetres of the most resistantsteel armours.The capability of most materials for defeating HEAT follows the "density law", which states that the penetration ofshaped chargejets is proportional to the square root of the shaped charge linerdensity(typicallycopper) divided by the square root of the target density. On a weight basis, lighter targets are more advantageous than heavier targets, but using large quantities of lightweight materials has obvious disadvantages in terms of mechanical layout. Certain materials have an optimal compromise in terms of density that makes them particularly useful in this role.

History

The earliest known composite armour for armoured vehicles was developed as part of theUS Army'sT95experimental series from the mid-1950s. The T95 featuredsiliceous-cored armourwhich contained a plate offused silicaglass between rolledsteelplates. The stopping power of glass exceeds that of steel armour on a thickness basis and in many cases glass is more than twice as effective as steel on a thickness basis. Although the T95 never entered production, a number of its concepts were used on theM60 Patton,and during the development stage (as the XM60) the siliceous-cored armour was at least considered for use, although it was not a feature of the production vehicles.

The first widespread use of a composite armour appears to have been on theSovietT-64.It used an armour known ascombination K,which apparently isglass-reinforced plasticsandwiched between inner and outer steel layers. Through a mechanism calledthixotropy,theresinchanges to a fluid under constant pressure, allowing the armour to bemouldedinto curved shapes. Later models of the T-64, along with newer designs, use aboron carbide-filled resinaggregatefor greatly improved protection.The Soviets also invested heavily inreactive armour,which allowed them some ability to control quality, even after production.

Among NATO nations and allies, the most common type ofcompositearmour today isChobham armour,first developed and used by the British in the experimentalFV 4211 tank,which was based onChieftain tankcomponents. Chobham uses multiple non-explosive reactive armour plates (NERA), which sandwich a layer of elastomer (like rubber) between two plates of steel armour. This was shown to dramatically increase the resistance to HEAT projectiles, even in comparison to other composite armour designs. Chobham was such an improvement that it was soon used on the new U.S.M1 Abramsmain battle tank(MBT) as well. The need to mount multiple angled plates, along with an outer steel layer to protect the armour array, gives theChallengerand Abrams their "slab sided" look.

The Soviets/Russians had a similar composite armour to the West's own "NERA", with rubber sandwiches between plates of steel.This armour was confirmed to be inside the T-72B's "Super Dolly Parton" armour, but is suspected to be inside the T-80A as well, since it is unlikely the Soviets would put worse armour in their "premier" tank.

Design

Chobham armour defeats HEAT warheads by disrupting the high speed jet generated by the warhead. The outer steel "burster" plate detonates the shell and protects the composite array from the blast, increasing the armour's multi hit abilities. After making it through the burster plate, the jet penetrates into the first NERA plate, and begins to compress the elastomer. The elastomer quickly reaches maximum compression and rapidly expands, pushing the two steel plates in opposite directions. It is the movement of the steel plates that disrupts the jet, both by feeding more material into the jet's path, and introducing lateral forces to break the jet apart. The effectiveness of the system was amply demonstrated inDesert Storm,where not a singleBritish ArmyChallenger tank was lost to enemy tank fire. (However, one was destroyed by friendly fire on March 25, 2003, killing two crew members after aHESHprojectile detonated on the commander's hatch causing high-velocity fragments to enter theturret.) Chobham-type armour is currently in its third generation and is used on modern western tanks such as theBritish Challenger 2and the AmericanM1 Abrams.The Abrams is also unique in its usage ofdepleted uranium armourplates in conjunction with composite armour, increasing overall vehicle protection. The Leopard 2A4 is similar in its use of tungsten inserts.

Use

All modern third-generation main battle tanks use composite armour arrays in their construction. While many of these vehicles feature the composite armour permanently integrated with the vehicle, the JapaneseType 10andType 90 Kyū-maruMBTs, FrenchLeclerc,IranianKarrar,TurkishAltay,IndianArjun,ItalianArieteand ChineseType 96/98 andType 99tanks use a modular composite armour, where sections of the composite armour can be easily and quickly switched out or upgraded with armour modules. The adoption of modular composite armour design facilitates far more efficient and easier upgrades and exchanges of the armour.

Soviet/Russian main battle tanks such asT-90sT-80Us and the Chinese Type 96/99s use composite armour in tandem withexplosive reactive armour(ERA), making it hard for shaped charge munitions such as HEAT projectiles and missile warheads to penetrate the frontal and a portion of their side armour. The most advanced versions of these armours such as theReliktandKontakt-5armour provide protection not only against shaped charges but alsokinetic energy penetratorsby using the explosive force to shear the projectile apart.

Applique armour has also been used in conjunction with composite armour to provide increased amounts of protection and to supplant existing composite arrays on a vehicle. The GermanLeopard 2A5featured distinctive arrowhead laminated armour modules that was mounted directly onto the turret composite arrays, increasing protection markedly above the previous 2A4 model.

Composite armour has since been applied to smaller vehicles, right down tojeep-sized automobiles. Many of these systems are applied as upgrades to existing armour, which makes them difficult to place around the entire vehicle. Nevertheless, they are often surprisingly effective; upgrades withMEXASceramic armour to CanadianM113swere carried out in the 1990s, after it was realized that it would offer more protection than newly builtIFVslike theM2 Bradley.

Improvised

In 2004, AmericanMarvin Heemeyerused anad hoccomposite armour on hisKomatsu D355Abulldozer( "which he called the MK Tank and in popular culture, the Killdozer" ) used in a rampage in response to a dispute with the city he lived in over a zoning issue. The armour, at some places a 1 foot (30 cm) thick, consisted of a layer ofconcretesandwiched between layers ofsteel,successfully rendering the vehicle impervious tosmall armsfire and small explosives used by law enforcement in an attempt to stop the vehicle.

See also

• Advanced Modular Armor Protection(AMAP)
• Chobham armour
• Combination K
• Compound armour
• Kanchan armour
• MEXAS
• Plastic composite
• Pykrete