Vehicle armour

• 1. Ironclads And The First Plating

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  In 1862, the ironclad warship CSS Virginia engaged the USS Monitor in a battle that changed naval warfare forever. This clash proved that thick metal plates could withstand cannon fire better than traditional wooden hulls. Early European iron armour consisted of 10 to 12.5 centimeters of wrought iron backed by up to one meter of solid wood. Shipbuilders soon realized steel was significantly stronger and replaced wrought iron entirely. By the early 20th century, belt armor covered ships from the deck down some way below the waterline. Designers often fitted this belt at an inclined angle to improve protection against incoming shells. When struck by a shell or torpedo, the belt armor was designed to prevent penetration by being too thick for the warhead to penetrate. Often, the main belt armor was supplemented with a torpedo bulkhead spaced several meters behind the main belt.

• 2. Metals That Defy Impact

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  Rolled homogeneous armor is strong, hard, and tough because it 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 irons out the grain structure in the steel, removing imperfections which would reduce the strength. Titanium has almost twice the density of aluminum but can have a yield strength similar to high strength steels. The USAF A-10 Thunderbolt II utilized a bathtub-shaped titanium enclosure for the pilot. Soviet/Russian-built Sukhoi Su-25 ground-attack aircraft also used this same protective design. Depleted uranium can be used in tank armor sandwiched between sheets of steel armor plate. Some late-production M1A1HA and M1A2 Abrams tanks built after 1998 have DU reinforcement as part of the armor plating in the front of the hull.

• 3. Ceramics And Composite Layers

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  High speed photography showed that ceramic material shatters as the HEAT round penetrates. The highly energetic fragments destroy the geometry of the metal jet generated by the hollow charge. Ceramic layers can also be used as part of composite armor solutions. Composite armor was initially developed in the 1940s although it did not enter service until much later. Soviet main battle tanks from the T-64 onward utilized composite armor which often consisted of some low density filler between relatively thick steel plates. The T-64 turret had a layer of ceramic balls and aluminum sandwiched between layers of cast steel armor. Later T-80 and T-72 turrets contained NERA elements similar to those discussed above. Modern Western and Israeli main battle tanks largely consist of non-explosive reactive armor elements.

• 4. Ships And Aircraft Defense

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  Armour plating is not common on aircraft which generally rely on their speed and maneuverability to avoid attacks from enemy aircraft and ground fire. Only the vital parts of an aircraft such as the ejection seat and engines are usually armored. Windscreens of larger aircraft are generally made of impact-resistant laminated materials even on civilian craft. These prevent damage from bird strikes or other debris. Belt armor covers warships from the deck down some way below the waterline. If built within the hull rather than forming the outer hull, it can be fitted at an inclined angle to improve protection. Deck armor on aircraft carriers is usually at the flight deck level but on some early carriers was at the hangar deck.

• 5. Angles That Deflect Fire

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  Sloped armor is armor that is mounted at a non-vertical and non-horizontal angle typically on tanks and other armored fighting vehicles. For a given normal to the surface of the armor its plate thickness increasing armor slope improves the armor's level of protection by increasing the thickness measured on a horizontal plane. The increased protection caused by increasing the slope while keeping the plate thickness constant 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 armor in armored vehicle design. 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.

• 6. Explosive And Active Shields

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  Explosive reactive armor 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. Traditional light ERA is less effective against kinetic penetrators but heavy reactive armor offers better protection. The only example currently in widespread service is Russian Kontakt-5. Explosive reactive armor poses a threat to friendly troops near the vehicle. Active protection systems use a sensor to detect an incoming projectile and explosively launch a counter-projectile into its path. Slat armor is designed to protect against anti-tank rocket and missile attacks where the warhead is a shaped charge.