Armour-piercing ammunition (AP) is a type of projectile designed to penetrate armour protection, most often including naval armour, body armour, and vehicle armour.
Ductility refers to the ability of a material to sustain significant plastic deformation before fracture. Plastic deformation is the permanent distortion of a material under applied stress, as opposed to elastic deformation, which is reversible upon removing the stress. Ductility is a critical mechanical performance indicator, particularly in applications that require materials to bend, stretch, or deform in other ways without breaking. The extent of ductility can be quantitatively assessed using the percent elongation at break, given by the equation:
A projectile is an object that is propelled by the application of an external force and then moves freely under the influence of gravity and air resistance. Although any objects in motion through space are projectiles, they are commonly found in warfare and sports.
In mechanics and physics, shock is a sudden acceleration caused, for example, by impact, drop, kick, earthquake, or explosion. Shock is a transient physical excitation.
A shock absorber or damper is a mechanical or hydraulic device designed to absorb and damp shock impulses. It does this by converting the kinetic energy of the shock into another form of energy which is then dissipated. Most shock absorbers are a form of dashpot.
Terminal ballistics is a sub-field of ballistics concerned with the behavior and effects of a projectile when it hits and transfers its energy to a target.
The field of strength of materials typically refers to various methods of calculating the stresses and strains in structural members, such as beams, columns, and shafts. The methods employed to predict the response of a structure under loading and its susceptibility to various failure modes takes into account the properties of the materials such as its yield strength, ultimate strength, Young's modulus, and Poisson's ratio. In addition, the mechanical element's macroscopic properties such as its length, width, thickness, boundary constraints and abrupt changes in geometry such as holes are considered.
A material is brittle if, when subjected to stress, it fractures with little elastic deformation and without significant plastic deformation. Brittle materials absorb relatively little energy prior to fracture, even those of high strength. Breaking is often accompanied by a sharp snapping sound.
The light-gas gun is an apparatus for physics experiments. It is a highly specialized gun designed to generate extremely high velocities. It is usually used to study high-speed impact phenomena, such as the formation of impact craters by meteorites or the erosion of materials by micrometeoroids. Some basic material research relies on projectile impact to create high pressure; such systems are capable of forcing liquid hydrogen into a metallic state.
Stopping power is the ability of a weapon – typically a ranged weapon such as a firearm – to cause a target to be incapacitated or immobilized. Stopping power contrasts with lethality in that it pertains only to a weapon's ability to make the target cease action, regardless of whether or not death ultimately occurs. Which ammunition cartridges have the greatest stopping power is a much-debated topic.
In materials science, the Charpy impact test, also known as the Charpy V-notch test, is a standardized high strain rate test which determines the amount of energy absorbed by a material during fracture. Absorbed energy is a measure of the material's notch toughness. It is widely used in industry, since it is easy to prepare and conduct and results can be obtained quickly and cheaply. A disadvantage is that some results are only comparative. The test was pivotal in understanding the fracture problems of ships during World War II.
The Izod impact strength test is an ASTM standard method of determining the impact resistance of materials. A pivoting arm is raised to a specific height and then released. The arm swings down hitting a notched sample, breaking the specimen. The energy absorbed by the sample is calculated from the height the arm swings to after hitting the sample. A notched sample is generally used to determine impact energy and notch sensitivity.
The coefficient of restitution, is the ratio of the relative velocity of separation after collision to the relative velocity of approach before collision. It can also be defined as the square root of the ratio of the final kinetic energy to the initial kinetic energy. It normally ranges from 0 to 1 where 1 would be a perfectly elastic collision. A perfectly inelastic collision has a coefficient of 0, but a 0 value does not have to be perfectly inelastic. It is measured in the Leeb rebound hardness test, expressed as 1000 times the COR, but it is only a valid COR for the test, not as a universal COR for the material being tested.
An impact attenuator, also known as a crash cushion, crash attenuator, or cowboy cushion, is a device intended to reduce the damage to structures, vehicles, and motorists resulting from a motor vehicle collision. Impact attenuators are designed to absorb the colliding vehicle's kinetic energy. They may also be designed to redirect the vehicle away from the hazard or away from roadway machinery and workers. Impact attenuators are usually placed in front of fixed structures near highways, such as gore points, crash barrier introductions, or overpass supports. Temporary versions may be used for road construction projects.
Frangible bullets are intended to disintegrate into tiny particles upon target impact to minimize their penetration of other objects. Small particles are slowed more rapidly by air resistance, and are less likely to cause injury or damage to persons and objects distant from the point of bullet impact.
Armour-piercing fin-stabilized discarding sabot (APFSDS), long dart penetrator, or simply dart ammunition is a type of kinetic energy penetrator ammunition used to attack modern vehicle armour. As an armament for main battle tanks, it succeeds Armour-Piercing Discarding Sabot (APDS) ammunition, which is still used in small or medium caliber weapon systems.
Package cushioning is used to protect items during shipment. Vibration and impact shock during shipment and loading/unloading are controlled by cushioning to reduce the chance of product damage.
Ceramic armor is armor used by armored vehicles and in personal armor to resist projectile penetration through its high hardness and compressive strength. In its most basic form, it consists of two primary components: A ceramic layer on the outer surface, called the "strike face," backed up by a ductile fiber reinforced plastic composite or metal layer. The role of the ceramic is to (1) fracture the projectile or deform the projectile nose upon impact, (2) erode and slow down the projectile remnant as it penetrates the shattered ceramic layer, and (3) distribute the impact load over a larger area, which can be absorbed by ductile polymer or metallic backings. Ceramics are often used where light weight is important, as they weigh less than metal alloys for a given degree of resistance. The most common materials are alumina, boron carbide, and, to a lesser extent, silicon carbide.
A kinetic energy weapon is a projectile weapon based solely on a projectile's kinetic energy to inflict damage to a target, instead of using any explosive, incendiary/thermal, chemical or radiological payload. All kinetic weapons work by attaining a high flight speed — generally supersonic or even up to hypervelocity — and collide with their targets, converting its kinetic energy and relative impulse into destructive shock waves, heat and cavitation. In kinetic weapons with unpowered flight, the muzzle velocity or launch velocity often determines the effective range and potential damage of the kinetic projectile.
