Military vehicles are commonly armoured (or armored; see spelling
differences) to withstand the impact of shrapnel, bullets, missiles or
shells, protecting the personnel inside from enemy fire. Such vehicles
include armoured fighting vehicles like tanks, aircraft and ships.
Civilian vehicles may also be armoured. These vehicles include cars
used by reporters, officials and others in conflict zones or where
violent crime is common, and presidential limousines. Civilian
armoured cars are also routinely used by security firms to carry money
or valuables to reduce the risk of highway robbery or the hijacking of
Armour may also be used in vehicles to protect from threats other than
a deliberate attack. Some spacecraft are equipped with specialised
armour to protect them against impacts from micrometeoroids or
fragments of space junk. Modern aircraft powered by jet engines
usually have them fitted with a sort of armour in the form of an
aramid composite kevlar bandage around the fan casing or debris
containment walls built into the casing of their gas turbine engines
to prevent injuries or airframe damage should the fan, compressor, or
turbine blades break free.
The design and purpose of the vehicle determines the amount of armour
plating carried, as the plating is often very heavy and excessive
amounts of armour restrict mobility. In order to decrease this
problem, some new materials (nanomaterials) and material compositions
are being researched which include buckypaper, and aluminium foam
4 Armoured fighting vehicles
4.2 Spall liners
4.9 Electrically charged
5 See also
7 External links
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Rolled homogeneous armour is strong, hard, and tough (does not shatter
when struck with a fast, hard blow).
Steel with these characteristics
is produced by processing cast steel billets of appropriate size and
then rolling them into plates of required thickness. Rolling and
forging (hammering the steel when it is red hot) irons out the grain
structure in the steel, removing imperfections which would reduce the
strength of the steel. Rolling also elongates the grain structure in
the steel to form long lines, which enable the stress the steel is
placed under when loaded to flow throughout the metal, and not be
concentrated in one area.
The British Fox CVR(W) was built largely of aluminium.
Aluminium is used when light weight is a necessity. It is most
commonly used on APCs and armoured cars.
Wrought iron was used on ironclad warships. Early European iron armour
consisted of 10 to 13 cm of wrought iron backed by up to one
meter of solid wood.
Titanium has almost twice the density of aluminium, but is as strong
as iron. So, despite being more expensive, it finds an application in
areas where weight is a concern, such as personal armour and military
aviation. Some notable examples of its use include the
Thunderbolt II and the Soviet/Russian-built
Sukhoi Su-25 ground-attack
aircraft, utilising a bathtub-shaped titanium enclosure for the pilot,
as well as the Soviet/Russian
Mil Mi-24 attack helicopter.
Because of its high density, depleted uranium can also be used in tank
armour, sandwiched between sheets of steel armour plate. For instance,
some late-production M1A1HA and M1A2 Abrams tanks built after 1998
have DU reinforcement as part of the armour plating in the front of
the hull and the front of the turret, and there is a program to
upgrade the rest (see Chobham armour).
Main article: Plastic armour
Plastic metal was a type of vehicle armour originally developed for
merchant ships by the
British Admiralty in 1940. The original
composition was described as 50% clean granite of half-inch size, 43%
of limestone mineral, and 7% of bitumen. It was typically applied in a
layer two inches thick and backed by half an inch of steel.
Plastic armour was highly effective at stopping armour piercing
bullets because the hard granite particles would deflect the bullet,
which would then lodge between plastic armour and the steel backing
Plastic armour could be applied by pouring it into a cavity
formed by the steel backing plate and a temporary wooden form.
Main article: Bulletproof glass
Ballistic test of a bullet-resistant glass panel
Bulletproof glass is a colloquial term for glass that is particularly
resistant to being penetrated when struck by bullets. The industry
generally refers to it as bullet-resistant glass or transparent
Bullet-resistant glass is usually constructed using a strong but
transparent material such as polycarbonate thermoplastic or by using
layers of laminated glass. The desired result is a material with the
appearance and light-transmitting behaviour of standard glass, which
offers varying degrees of protection from small arms fire.
The polycarbonate layer, usually consisting of products such as
Armormax, Makroclear, Cyrolon,
Lexan or Tuffak, is often sandwiched
between layers of regular glass. The use of plastic in the laminate
provides impact-resistance, such as physical assault with a hammer, an
axe, etc. The plastic provides little in the way of bullet-resistance.
The glass, which is much harder than plastic, flattens the bullet and
thereby prevents penetration. This type of bullet-resistant glass is
usually 70–75 mm (2.8–3.0 in) thick.
Bullet-resistant glass constructed of laminated glass layers is built
from glass sheets bonded together with polyvinyl butyral, polyurethane
or ethylene-vinyl acetate. This type of bullet-resistant glass has
been in regular use on combat vehicles since World War II; it is
typically about 100–120 mm (3.9–4.7 in) thick and is
usually extremely heavy.
Newer materials are being developed. One such, aluminium oxynitride,
is much lighter but at US$10–15 per square inch is much more costly.
Ceramic's precise mechanism for defeating HEAT was uncovered in the
1980s. High speed photography showed that the ceramic material
shatters as the HEAT round penetrates, the highly energetic fragments
destroying the geometry of the metal jet generated by the hollow
charge, greatly diminishing the penetration.
Ceramic layers can also
be used as part of composite armour solutions. The high hardness of
some ceramic materials serves as a disruptor that shatters and spreads
the kinetic energy of projectiles.
Plasan Sand Cat
Plasan Sand Cat light (5t) military vehicle featuring integrated
composite armoured body
Main article: Composite armour
Composite armour is armour consisting of layers of two or more
materials with significantly different physical properties; steel and
ceramics are the most common types of material in composite armour.
Composite armour was initially developed in the 1940s, although it did
not enter service until much later and the early examples are often
ignored in the face of newer armour such as Chobham armour. Composite
armour's effectiveness depends on its composition and may be effective
against kinetic energy penetrators as well as shaped charge munitions;
heavy metals are sometimes included specifically for protection from
kinetic energy penetrators.
Diagram of common elements of warship armour. The belt armour is
denoted by "A".
Belt armour is a layer of armour-plating outside the hull (watercraft)
of warships, typically on battleships, battlecruisers, cruisers and
some aircraft carriers.
Typically, the belt covered from the deck down someway below the
waterline of the ship. If built within the hull, rather than forming
the outer hull, it could be fitted at an inclined angle to improve the
When struck by a shell or torpedo, the belt armour is designed to
prevent penetration, by either being too thick for the warhead to
penetrate, or sloped to a degree that would deflect either projectile.
Often, the main belt armour was supplemented with a torpedo bulkhead
spaced several meters behind the main belt, designed to maintain the
ship's watertight integrity even if the main belt were penetrated.
The air-space between the belt and the hull also adds buoyancy.
Several wartime vessels had belt armour that was thinner or shallower
than was desirable, to speed production and conserve resources.
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Armour plating is not common on aircraft, which generally rely on
their speed and manoeuvrability to avoid ground fire, rather than
trying to resist impacts. Additionally, any armour capable of stopping
large-calibre anti-aircraft fire or missile fragments would result in
an unacceptable weight penalty. So, only the vital parts of an
aircraft, such as the ejection seat and engines, are usually armoured.
This is one area where titanium is used extensively as armour plating.
For example, in the American Fairchild Republic A-10 Thunderbolt II
and the Soviet-built
Sukhoi Su-25 ground attack aircraft, as well as
Mil Mi-24 Hind ground-attack helicopter, the pilot sits in a
titanium enclosure known as the "bathtub" for its shape. In addition,
the windscreens of larger aircraft are generally made of
impact-resistant, laminated materials, even on civilian craft, to
prevent damage from bird strikes or other debris.
Armoured fighting vehicles
Main article: Armoured fighting vehicle
The most heavily armoured vehicles today are the main battle tanks,
which are the spearhead of the ground forces, and are designed to
withstand anti-tank missiles, kinetic energy penetrators, NBC threats
and in some tanks even steep-trajectory shells. The Israeli Merkava
tanks were designed in a way that each tank component functions as
additional back-up armour to protect the crew. Outer armour is modular
and enables quick replacement of damaged armour.
For efficiency, the heaviest armour on an armoured fighting vehicle
(AFV) is placed on its front.
Tank tactics require the vehicle to
always face the likely direction of enemy fire as much as possible,
even in defence or withdrawal operations.
Sloping and curving armour can both increase its protection. Given a
fixed thickness of armour plate, a projectile striking at an angle
must penetrate more armour than one impacting perpendicularly. An
angled surface also increases the chance of deflecting a projectile.
This can be seen on v-hull designs, which direct the force of an
Improvised explosive device
Improvised explosive device or landmine away from the crew
compartment, increasing crew survivability.
Beginning during the Cold War, many AFVs have spall liners inside of
the armour, designed to protect crew and equipment inside from
fragmentation (spalling) released from the impact of enemy shells,
especially high explosive squash head warheads. Spall liners are made
of Kevlar, Dyneema, Spectra Shield, or similar materials.
Vehicle composite add-on armour kit
Appliqué armour, or add-on armour, consists of extra plates
mounted onto the hull or turret of an AFV. The plates can be made of
any material and are designed to be retrofitted to an AFV to withstand
weapons that can penetrate the original armour of the vehicle.
An advantage of appliqué armour is the possibility to tailor the
vehicle's protection level to a specific threat scenario.
Main article: Improvised vehicle armour
Vehicle armour is sometimes improvised in the midst of an armed
conflict by vehicle crews or individual units. In World War II,
British, Canadian and Polish tank crews welded spare strips of tank
track to the hulls of their Sherman tanks. U.S. tank crews often
added sand bags in the hull and turrets on Sherman tanks, often in an
elaborate cage made of girders. Some Sherman tanks were up-armoured in
the field with glacis plates and other armour cut from knocked-out
tanks to create Improvised Jumbos, named after the heavily armoured
M4A3E2 assault tank. In the Vietnam War, U.S. "gun trucks" were
armoured with sandbags and locally fabricated steel armour plate.
More recently, U.S. troops in Iraq armoured Humvees and various
military transport vehicles with scrap materials: this came to be
known as "hillbilly armor" or "haji armor" by the Americans.
Moreover there was the Killdozer incident, with the modified bulldozer
being armored with steel and concrete composite, which proved to be
highly resistant to small arms.
Main article: Spaced armour
Sturmgeschütz III with spaced armour plates.
Armour with two or more plates spaced a distance apart, called spaced
armour, has been in use since the First World War, where it was used
Schneider CA1 and Saint-Chamond tanks.
Spaced armour can be
advantageous in several situations. For example, it can reduce the
effectiveness of kinetic energy penetrators because the interaction
with each plate can cause the round to tumble, deflect, deform, or
disintegrate. This effect can be enhanced when the armour is sloped.
Spaced armour can also offer increased protection against HEAT
projectiles. This occurs because the shaped charge warhead can
detonate prematurely (at the first surface), so that the metal jet
that is produced dissipates its energy before reaching the main
armour. Sometimes the interior surfaces of these hollow cavities are
sloped, presenting angles to the anticipated path of the shaped
charge's jet in order to further dissipate its power. Taken to the
extreme, relatively thin armour plates, metal mesh, or slatted plates,
much lighter than fully protective armour, can be attached as side
skirts or turret skirts to provide additional protection against such
weapons. This can be seen in middle and late-
World War II
World War II German
tanks, as well as many modern AFVs. Taken as a whole, spaced armour
can provide significantly increased protection while saving weight.
Whipple shield uses the principle of spaced armour to
protect spacecraft from the impacts of very fast micrometeoroids. The
impact with the first wall melts or breaks up the incoming particle,
causing fragments to be spread over a wider area when striking the
Merkava features extreme sloped armour on the turret
Main article: Sloped armour
Sloped armour is armour that is mounted at a non-vertical and
non-horizontal angle, typically on tanks and other armoured fighting
vehicles. For a given normal to the surface of the armour, its plate
thickness, increasing armour slope improves the armour's level of
protection by increasing the thickness measured on a horizontal plane,
while for a given area density of the armour the protection can be
either increased or reduced by other sloping effects, depending on the
armour materials used and the qualities of the projectile hitting it.
The increased protection caused by increasing the slope while keeping
the plate thickness constant, is due to a proportional increase of
area density and thus mass, and thus offers no weight benefit.
Therefore, the other possible effects of sloping, such as deflection,
deforming and ricochet of a projectile, have been the reasons to apply
sloped armour in armoured vehicles design. Another motive is the fact
that sloping armour is a more efficient way of covering the necessary
equipment since it encloses less volume with less material. The
sharpest angles are usually seen on the frontal glacis plate, both as
it is the hull side most likely to be hit and because there is more
room to slope in the longitudinal direction of a vehicle.
M60A1 Patton tank with Israeli Blazer ERA.
Main article: Reactive armour
Explosive reactive armour, initially developed by German researcher
Manfred Held while working in Israel, uses layers of high explosive
sandwiched between steel plates. When a shaped-charge warhead hits,
the explosive detonates and pushes the steel plates into the warhead,
disrupting the flow of the charge's liquid metal penetrator (usually
copper at around 500 degrees Celsius; it can be made to flow like
water by sufficient pressure). Traditional "light" ERA is less
effective against kinetic penetrators. "Heavy" reactive armour,
however, offers better protection. The only example currently in
widespread service is Russian Kontakt-5.
Explosive reactive armour
poses a threat to friendly troops near the vehicle.
Non-explosive reactive armour is an advanced spaced armour which uses
materials which change their geometry so as to increase protection
under the stress of impact.
Active protection systems use a sensor to detect an incoming
projectile and explosively launch a counter-projectile into its path.
Main article: Slat armor
IDF Caterpillar D9
IDF Caterpillar D9 armoured bulldozer with slat armour (in addition to
armour plates and bulletproof windows). The D9 armour deflected RPG
rockets and even
9K11 Malyutka (AT-3 Sagger) ATGMs.
Slat armour is designed to protect against anti-tank rocket and
missile attacks, where the warhead is a shaped charge. The slats are
spaced so that the warhead is either partially deformed before
detonating, or the fuzing mechanism is damaged, thereby preventing
detonation entirely. As shaped charges rely on very specific structure
to create a jet of hot metal, any disruption to this structure greatly
reduces the effectiveness of the warhead. Slat armour can be
defeated by tandem-charge designs such as the
RPG-27 and RPG-29.
Electrically charged armour is a recent development in the United
Kingdom by the Defence Science and Technology
Laboratory. A vehicle is fitted with two
thin shells, separated by insulating material. The outer shell holds
an enormous electric charge, while the inner shell is at ground. If an
incoming HEAT jet penetrates the outer shell and forms a bridge
between the shells, the electrical energy discharges through the jet,
disrupting it. Trials have so far been extremely promising, and it is
hoped that improved systems could protect against KE penetrators. The
developers of the
Future Rapid Effect System
Future Rapid Effect System (FRES) series of armoured
vehicles are considering this technology.
Active protection system
Armoured fighting vehicle
Main battle tank
Non-military armoured vehicles
^ "Containment Device Transport Armor : Pinnacle Armor –
Body Armor and Armoring Products". Pinnacle Armor. Archived from the
original on September 28, 2011. Retrieved 2012-01-29.
Buckypaper armour". Slipperybrick.com. 2008-10-19. Retrieved
^ "Lightweight aluminum foam armour plates". Ntnu.no. Retrieved
^ those converted from other warships
^ Katzman, Joe (2007-04-26). "In Praise of Senator Biden: Survivable
Rides for the Troops". Winds of Change.NET. Retrieved
Oxford English Dictionary
Oxford English Dictionary "appliqué, n. and adj: "Ornamental
needlework in which small decorative pieces of fabric are sewn or
stuck on to a fabric or garment to form a pattern or trim; the
practice of this as a technique or activity; (also) (a piece of)
decoration or trim made in this way. Also in extended use in
metalwork, and fig". adj. "Of fabric or a garment: decorated by sewing
or sticking on small pieces of fabric to form a pattern or trim; (of
decoration, trim, etc.) attached in this way".
^ Gary W. Cooke Combat Vehicle Protection 1 August 2004. cites "FM
3-22.34 TOW Weapon System." and "FM 5-103 Survivability."
^ US Patent 6962102 -
Armour constructions US Patent Issued on
November 8, 2005. PatentStorm, Retrieved 2009-02-04
^ a b Moran, Michael. "Frantically, the Army tries to armour Humvees:
Soft-skinned workhorses turning into death traps," MSNBC, April 15,
^ Gardiner, Paul S. "Gun Trucks: Genuine Examples of American
Ingenuity," Archived 2007-11-02 at the Wayback Machine. Army
Logistician, PB 700-03-4, Vol. 35, No. 4, July–August 2003, Army
Combined Arms Support Command, Fort Lee, Virginia. ISSN 0004-2528
Armour for Stryker". Defense-update.com. Retrieved
^ "BAE's LROD Cage Armor". Defenseindustrydaily.com. 2011-03-15.
^ U.S. Military Uses the Force (Wired News)
^ 'Star Trek' shields to protect supertanks (The Guardian)
^ 'Electric armour' vaporises anti-tank grenades and shells
^ MoD Develops 'Electric Armour' Archived February 17, 2008, at the
^ "New Age Electric Armour – Tough enough to face modern
threats". Armedforces-int.com. Archived from the original on
2009-05-02. Retrieved 2012-01-29.
^ "Add-On – Reactive Armor Suits". Defense-update.com.
2006-04-25. Retrieved 2012-01-29.
^ "Advanced Add-on Armor for Light Vehicles". Defense-update.com.
2006-04-25. Retrieved 2012-01-29.
Wikimedia Commons has media related to Armoured vehicles.
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Modern armour types
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