Composite armour
Encyclopedia
Composite armour is a type of vehicle armour
consisting of layers of different material such as metal
s, plastics, ceramic
s or air. Most composite armour 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 defeat high explosive anti-tank
(HEAT) rounds.
HEAT had posed a serious threat to armoured vehicles since its introduction in World War II
. Lightweight and small, HEAT rounds could nevertheless penetrate hundreds of millimetres of the hardest steel armours
. The capability of most materials for defeating HEAT follows the "density law", which states that the penetration of shaped charge
jets is proportional to the square root of the shaped charge liner density
(typically copper
) 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 a sweet spot
in terms of density that makes them particularly useful in this role.
experimental series from the mid-1950s. The T95 featured "siliceous-cored armor" which contained a plate of fused silica glass
between rolled steel
plates. The stopping power of glass exceeds that of armour steel on a thickness basis and in many cases glass is more than twice as good as steel on a thickness basis. Although the T95 never entered production, a number of its concepts were used on the M60 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 the Soviet T-64
. It used an armour known as Combination K
, which apparently is glass-reinforced plastic
sandwiched between inner and outer steel layers. Through a mechanism called thixotropy
, the resin
changes to a fluid under constant pressure, allowing the armour to be moulded into curved shapes. Later models of the T-64, along with newer designs, used a boron carbide
-filled resin aggregate
for greatly improved protection. However the quality of the tanks produced during this era varied widely; if the boron carbide was not available in time to meet production quota
s, the tank would be shipped with any filler that could be found, and sometimes nothing at all. In order to deal with these problems, the Soviets invested heavily in reactive armour
, which allowed them some ability to control quality, even after production.
The most common type of composite
armour today is Chobham armour
, first developed and used by the British in the experimental FV 4211 tank, which was based on Chieftain tank
components. Chobham sandwiches a layer of ceramic
between two plates of steel armour, which was shown to dramatically increase the resistance to HEAT rounds, even in comparison to other composite armour designs. Chobham was such an improvement that it was soon used on the new U.S.
M1 Abrams
main battle tank
(MBT) as well. It is the fabrication of the ceramic in large tiles that gives the Challenger and Abrams their "slab sided" look.
, greatly diminishing the penetration. The effectiveness of the system was amply demonstrated in Desert Storm, where not a single British Army
Challenger tank was lost to enemy tank fire. However, one was destroyed by friendly fire on March 25, 2003 killing two crew members after a HESH round detonated on the commander's hatch
causing high velocity fragments to enter the turret
. Chobham-type armour is currently in its third generation and is used on modern western tanks such as the British Challenger 2
and the American M1 Abrams
.
, Indian Arjun MBT
, Japanese Type 90 tank, Pakistan's Al-Khalid tank and Chinese Type 96
/98 and Type 99
tanks use modular composite armour. The adoption of Modular composite armour design facilitated upgrading and exchange of the armour.
Soviet/Russian T-80
Us and Pakistan Al-Khalid use composite armour in tandem with the explosive reactive armour (ERA), making it hard for missiles and tank rounds to penetrate the frontal and a portion of their side armour.
Composite armour has since been applied to smaller vehicles, right down to jeep
-sized. 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; ceramic upgrades to Canadian M-113
s were carried out in the 1990s, after it was realized that it would offer more protection than newly built APCs
like the M2 Bradley
.
used an ad-hoc composite armour on his Komatsu D355A bulldozer
("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 foot thick, consisted of a layer of concrete
sandwiched between layers of steel
, successfully rendering the vehicle impervious against small arms
fire.
Vehicle armour
Military vehicles are commonly armoured to withstand the impact of shrapnel, bullets, missiles, or shells, protecting the personnel inside from enemy fire. Such vehicles include tanks, aircraft, and ships....
consisting of layers of different material such as metal
Metal
A metal , is an element, compound, or alloy that is a good conductor of both electricity and heat. Metals are usually malleable and shiny, that is they reflect most of incident light...
s, plastics, ceramic
Ceramic
A ceramic is an inorganic, nonmetallic solid prepared by the action of heat and subsequent cooling. Ceramic materials may have a crystalline or partly crystalline structure, or may be amorphous...
s or air. Most composite armour 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 defeat high explosive anti-tank
High explosive anti-tank
High explosive anti-tank warheads are made of an explosive shaped charge that uses the Munroe effect to create a very high-velocity partial stream of metal in a state of superplasticity that can punch through solid armor....
(HEAT) rounds.
HEAT had posed a serious threat to armoured vehicles since its introduction in World War II
World War II
World War II, or the Second World War , was a global conflict lasting from 1939 to 1945, involving most of the world's nations—including all of the great powers—eventually forming two opposing military alliances: the Allies and the Axis...
. Lightweight and small, HEAT rounds could nevertheless penetrate hundreds of millimetres of the hardest steel armours
Rolled homogeneous armour
Rolled homogeneous armour is a type of steel which is used to armour vehicles.-Composition:Armoured steel must be hard yet impervious to shock in order to resist high velocity metal projectiles. Steel with these characteristics is produced by processing cast steel billets of appropriate size and...
. The capability of most materials for defeating HEAT follows the "density law", which states that the penetration of shaped charge
Shaped charge
A shaped charge is an explosive charge shaped to focus the effect of the explosive's energy. Various types are used to cut and form metal, to initiate nuclear weapons, to penetrate armor, and in the oil and gas industry...
jets is proportional to the square root of the shaped charge liner density
Density
The mass density or density of a material is defined as its mass per unit volume. The symbol most often used for density is ρ . In some cases , density is also defined as its weight per unit volume; although, this quantity is more properly called specific weight...
(typically copper
Copper
Copper is a chemical element with the symbol Cu and atomic number 29. It is a ductile metal with very high thermal and electrical conductivity. Pure copper is soft and malleable; an exposed surface has a reddish-orange tarnish...
) 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 a sweet spot
Sweet spot
Sweet spot may refer to:*Sweet spot *Sweet spot *Sweet spot...
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 the US Army's T95T95
The T95 was an American prototype medium tank developed from 1955 to 1959. These tanks used many advanced or unusual features, such as siliceous-cored armor, a new transmission, and the OPTAC fire-control system...
experimental series from the mid-1950s. The T95 featured "siliceous-cored armor" which contained a plate of fused silica glass
Glass
Glass is an amorphous solid material. Glasses are typically brittle and optically transparent.The most familiar type of glass, used for centuries in windows and drinking vessels, is soda-lime glass, composed of about 75% silica plus Na2O, CaO, and several minor additives...
between rolled steel
Steel
Steel is an alloy that consists mostly of iron and has a carbon content between 0.2% and 2.1% by weight, depending on the grade. Carbon is the most common alloying material for iron, but various other alloying elements are used, such as manganese, chromium, vanadium, and tungsten...
plates. The stopping power of glass exceeds that of armour steel on a thickness basis and in many cases glass is more than twice as good as steel on a thickness basis. Although the T95 never entered production, a number of its concepts were used on the M60 Patton
M60 Patton
The 105 mm Gun Full Tracked Combat Tank, M60, also known unofficially as the M60 Patton, is a first-generation main battle tank introduced in December 1960. It was widely used by the U.S. and its Cold War allies, especially those in NATO, and remains in service throughout the world today...
, 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 the Soviet T-64
T-64
The T-64 is a Soviet main battle tank, introduced in the early 1960s. It was used solely by the Soviet Army in its front-line divisions and was a more advanced counterpart to the T-62...
. It used an armour known as Combination K
Combination K
Combination K was a type of composite armor.- The mix :Combination K is a three-layer composite armor consisting of outer and inner layer of steel and middle layer of glass-reinforced plastic and a pack of ceramic plates.The T-72 tanks have their gun turret frontal armour composed of three...
, which apparently is glass-reinforced plastic
Glass-reinforced plastic
Fiberglass , is a fiber reinforced polymer made of a plastic matrix reinforced by fine fibers of glass. It is also known as GFK ....
sandwiched between inner and outer steel layers. Through a mechanism called thixotropy
Thixotropy
Thixotropy is the property of certain gels or fluids that are thick under normal conditions, but flow over time when shaken, agitated, or otherwise stressed...
, the resin
Resin
Resin in the most specific use of the term is a hydrocarbon secretion of many plants, particularly coniferous trees. Resins are valued for their chemical properties and associated uses, such as the production of varnishes, adhesives, and food glazing agents; as an important source of raw materials...
changes to a fluid under constant pressure, allowing the armour to be moulded into curved shapes. Later models of the T-64, along with newer designs, used a boron carbide
Boron carbide
Boron carbide is an extremely hard boron–carbon ceramic material used in tank armor, bulletproof vests, and numerous industrial applications...
-filled resin aggregate
Aggregate (composite)
Aggregate is the component of a composite material that resists compressive stress and provides bulk to the composite material. For efficient filling, aggregate should be much smaller than the finished item, but have a wide variety of sizes...
for greatly improved protection. However the quality of the tanks produced during this era varied widely; if the boron carbide was not available in time to meet production quota
Production quota
A production quota is a goal for the production of a good. It is typically set by a government or an organization, and can be applied to an individual worker, firm, industry or country. Quotas can be set high to encourage production, or can be used to limit production to control the supply of goods...
s, the tank would be shipped with any filler that could be found, and sometimes nothing at all. In order to deal with these problems, the Soviets invested heavily in reactive armour
Reactive armour
Reactive armour is a type of vehicle armour that reacts in some way to the impact of a weapon to reduce the damage done to the vehicle being protected. It is most effective in protecting against shaped charges and specially hardened long rod penetrators...
, which allowed them some ability to control quality, even after production.
The most common type of composite
Composite material
Composite materials, often shortened to composites or called composition materials, are engineered or naturally occurring materials made from two or more constituent materials with significantly different physical or chemical properties which remain separate and distinct at the macroscopic or...
armour today is Chobham armour
Chobham armour
Chobham armour is the name informally given to a composite armour developed in the 1960s at the British tank research centre on Chobham Common, Surrey, England...
, first developed and used by the British in the experimental FV 4211 tank, which was based on Chieftain tank
Chieftain tank
The FV 4201 Chieftain was the main battle tank of the United Kingdom during the 1960s and 1970s. It was one of the most advanced tanks of its era, and at the time of its introduction in 1966 had the most powerful main gun and heaviest armour of any tank in the world...
components. Chobham sandwiches a layer of ceramic
Ceramic
A ceramic is an inorganic, nonmetallic solid prepared by the action of heat and subsequent cooling. Ceramic materials may have a crystalline or partly crystalline structure, or may be amorphous...
between two plates of steel armour, which was shown to dramatically increase the resistance to HEAT rounds, even in comparison to other composite armour designs. Chobham was such an improvement that it was soon used on the new U.S.
United States
The United States of America is a federal constitutional republic comprising fifty states and a federal district...
M1 Abrams
M1 Abrams
The M1 Abrams is a third-generation main battle tank produced in the United States. It is named after General Creighton Abrams, former Army Chief of Staff and Commander of US military forces in Vietnam from 1968 to 1972. The M1 is a well armed, heavily armored, and highly mobile tank designed for...
main battle tank
Main battle tank
A main battle tank , also known as a battle tank or universal tank, is a tank that fills the heavy direct fire role of many modern armies. They were originally conceived to replace the light, medium, heavy and super-heavy tanks. Development was spurred onwards in the Cold War with the development...
(MBT) as well. It is the fabrication of the ceramic in large tiles that gives the Challenger and Abrams their "slab sided" look.
Design
Chobham'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 shaped chargeShaped charge
A shaped charge is an explosive charge shaped to focus the effect of the explosive's energy. Various types are used to cut and form metal, to initiate nuclear weapons, to penetrate armor, and in the oil and gas industry...
, greatly diminishing the penetration. The effectiveness of the system was amply demonstrated in Desert Storm, where not a single British Army
British Army
The British Army is the land warfare branch of Her Majesty's Armed Forces in the United Kingdom. It came into being with the unification of the Kingdom of England and Scotland into the Kingdom of Great Britain in 1707. The new British Army incorporated Regiments that had already existed in England...
Challenger tank was lost to enemy tank fire. However, one was destroyed by friendly fire on March 25, 2003 killing two crew members after a HESH round detonated on the commander's hatch
Hatch
Hatch may refer to:* Hatching, also called "cross-hatching", an artistic technique used to create tonal or shading effects using closely spaced parallel lines* Hatching, the emergence of a young animal from an egg...
causing high velocity fragments to enter the turret
Gun turret
A gun turret is a weapon mount that protects the crew or mechanism of a projectile-firing weapon and at the same time lets the weapon be aimed and fired in many directions.The turret is also a rotating weapon platform...
. Chobham-type armour is currently in its third generation and is used on modern western tanks such as the British Challenger 2
Challenger 2 tank
FV4034 Challenger 2 is a British main battle tank currently in service with the armies of the United Kingdom and Oman. It was designed and built by the British company Vickers Defence Systems . The manufacturer advertises it as the world's most reliable main battle tank...
and the American M1 Abrams
M1 Abrams
The M1 Abrams is a third-generation main battle tank produced in the United States. It is named after General Creighton Abrams, former Army Chief of Staff and Commander of US military forces in Vietnam from 1968 to 1972. The M1 is a well armed, heavily armored, and highly mobile tank designed for...
.
Usage
The French LeclercLeclerc
The AMX-56 Leclerc, commonly known as the Leclerc, is a main battle tank built by Nexter of France. It was named in honour of General Philippe Leclerc de Hauteclocque who led the French element of the drive towards Paris while in command of the Free French 2nd Armoured Division in World War...
, Indian Arjun MBT
Arjun MBT
The Arjun is a third generation main battle tank developed by India's Defence Research and Development Organization , for the Indian Army...
, Japanese Type 90 tank, Pakistan's Al-Khalid tank and Chinese Type 96
Type 96
The Type 96 is the latest Chinese third-generation main battle tank . Based on the Type 85-III design, the Type 96 entered service with the People's Liberation Army in 1997. As of 2005, an estimated 1,500 Type 96 tanks are currently in service with the PLA.Generally speaking, PLA's tank...
/98 and Type 99
Type 99
The Type 99, also known as ZTZ-99 and WZ-123, developed from the Type 98G , is a third generation main battle tank fielded by the Chinese People's Liberation Army. It is made to compete with other modern tanks...
tanks use modular composite armour. The adoption of Modular composite armour design facilitated upgrading and exchange of the armour.
Soviet/Russian T-80
T-80
The T-80 is a main battle tank designed and manufactured in the former Soviet Union. A development of the T-64, it entered service in 1976 and was the first production tank to be equipped with a gas turbine engine for main propulsion.the Swedish Stridsvagn 103 of 1971 used a gas turbine alongside...
Us and Pakistan Al-Khalid use composite armour in tandem with the explosive reactive armour (ERA), making it hard for missiles and tank rounds to penetrate the frontal and a portion of their side armour.
Composite armour has since been applied to smaller vehicles, right down to jeep
Jeep
Jeep is an automobile marque of Chrysler . The first Willys Jeeps were produced in 1941 with the first civilian models in 1945, making it the oldest off-road vehicle and sport utility vehicle brand. It inspired a number of other light utility vehicles, such as the Land Rover which is the second...
-sized. 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; ceramic upgrades to Canadian M-113
M113 armored personnel carrier
The M113 is a fully tracked armored personnel carrier that has formed the backbone of the United States Army's mechanized infantry units from the time of its first fielding in Vietnam in April 1962. The M113 was the most widely used armored vehicle of the U.S...
s were carried out in the 1990s, after it was realized that it would offer more protection than newly built APCs
Armoured personnel carrier
An armoured personnel carrier is an armoured fighting vehicle designed to transport infantry to the battlefield.APCs are usually armed with only a machine gun although variants carry recoilless rifles, anti-tank guided missiles , or mortars...
like the M2 Bradley
M2 Bradley
The Bradley Fighting Vehicle is an American fighting vehicle platform manufactured by BAE Systems Land and Armaments, formerly United Defense.As with other infantry fighting vehicles, the Bradley is designed to transport infantry with armor protection while providing covering fire to suppress enemy...
.
Improvised
In 2004, Marvin HeemeyerMarvin Heemeyer
Marvin John Heemeyer was a welder and an automobile muffler repair shop owner. Outraged over the outcome of a zoning dispute, he armored a Komatsu D355A bulldozer with layers of steel and concrete and used it on June 4, 2004, to demolish the town hall, a former judge's home, and other buildings in...
used an ad-hoc composite armour on his Komatsu D355A bulldozer
Bulldozer
A bulldozer is a crawler equipped with a substantial metal plate used to push large quantities of soil, sand, rubble, etc., during construction work and typically equipped at the rear with a claw-like device to loosen densely-compacted materials.Bulldozers can be found on a wide range of sites,...
("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 foot thick, consisted of a layer of concrete
Concrete
Concrete is a composite construction material, composed of cement and other cementitious materials such as fly ash and slag cement, aggregate , water and chemical admixtures.The word concrete comes from the Latin word...
sandwiched between layers of steel
Steel
Steel is an alloy that consists mostly of iron and has a carbon content between 0.2% and 2.1% by weight, depending on the grade. Carbon is the most common alloying material for iron, but various other alloying elements are used, such as manganese, chromium, vanadium, and tungsten...
, successfully rendering the vehicle impervious against small arms
Small arms
Small arms is a term of art used by armed forces to denote infantry weapons an individual soldier may carry. The description is usually limited to revolvers, pistols, submachine guns, carbines, assault rifles, battle rifles, multiple barrel firearms, sniper rifles, squad automatic weapons, light...
fire.
See also
- AMAPAdvanced Modular Armor ProtectionAdvanced Modular Armor Protection is modular composite armour concept, developed by the German company IBD Deisenroth Engineering. According to IBD AMAP is a 4th generation composite armour, making use of nano-ceramics and modern steel alloy technologies.AMAP is the successor of MEXAS.Some modules...
- Chobham armourChobham armourChobham armour is the name informally given to a composite armour developed in the 1960s at the British tank research centre on Chobham Common, Surrey, England...
- Combination KCombination KCombination K was a type of composite armor.- The mix :Combination K is a three-layer composite armor consisting of outer and inner layer of steel and middle layer of glass-reinforced plastic and a pack of ceramic plates.The T-72 tanks have their gun turret frontal armour composed of three...
- Kanchan armourKanchan armourKanchan Armour is the name informally given to a modular composite armour indigenously developed by India. The Kanchan Armour got its name from Kanchan Bagh , Hyderabad, Andhra Pradesh, India where the Defence Metallurgical Research Laboratory is located....
- MEXASMEXASThe Modular Expandable Armor System is a ceramic composite armour developed by the German company IBD Deisenroth Engineering. MEXAS was introduced in 1994 and has been applied on over 20,000 combat vehicles worldwide...