Spall liners for military vehicles protect soldiers from flying fragments (spall) of metal inside of the crew compartment. They’re made of energy-absorbing materials and can be fabricated into panels or blankets. Spall liners attach to the inside of a vehicle’s structural armor and line the interior surfaces of tanks, fighting vehicles, and personnel carriers. By reducing the risk of serious of injury to military personnel, these custom-fabricated components serve as a type of interior armor.
Elasto Proxy makes spall panels, spall blankets, and other types of spall linings for military land systems. We use water jet cutting to create smooth, straight lines and can make angled cuts for edges that conform to vehicle contours. With our custom fabrication capabilities, Elasto Proxy can create spall liners with fastener holes for permanent installation, or that support Velcro fasteners for temporary attachment. We can also laminate materials together to create strong, durable composites for military vehicles.
The Science of Spalling
When a mine or improvised explosive device (IED) is detonated, the impact may not be powerful enough to pierce the armor of a military vehicle. Yet the shock wave is still strong enough to pass through the structural armor and cause damage. That’s because the metal surfaces inside of a vehicle can only withstand so much stress before fracture occurs. If the impact from a pressure wave shatters this metal, spall is propelled towards the vehicle’s occupants at high velocities.
Mines and IEDs aren’t the only threats that armored vehicles face, however. With kinetic energy weapons, the mass and velocity of the projectile is designed to cause spalling inside of the vehicle. Chemical energy weapons such as high-explosive anti-tank (HEAT) systems can also defeat military vehicles from the inside out. Other sources of spall include small caliber ballistics, hand grenades, and shaped charges – devices that are designed to focus the effects of an explosive’s energy.
Spall Liners: Materials and Types
Spall liners for military vehicles are usually made of laminates of aramid, glass, or high-density polyethylene (HDPE) fibers, materials that provide strong impact resistance. Fire-retardant grades are used to promote solider safety. Early spall liners were made of E-glass laminates and developed in accordance with DEF STAN 93-111/1, a U.K. defense standard. U.S. military standards continue to evolve since the original MIL-L-62,474B specification. Today, some spall liners are laminated to ceramic plates.
There are two main types of spall linings. Spall panels are rubber-coated composites that use a resin system. They’re stiff, durable, and suitable for vehicle locations where visibility is high and physical support is low. Spall blankets are more flexible, and consist of layers of fibers that are encapsulated by a polymer for protection against moisture, wear, dust, and UV light. Both types of spall liners can incorporate part features such as holes for fasteners.
Spall Liners: Value-Added Manufacturing
Designers of military vehicles need to account for more than just spall liner materials and manufacturing methods. Tight tolerances are important because pressure waves can enter through “ballistic windows”, small gaps between joined surfaces. The way that protective products are installed and removed is important, too. Metal fasteners require hand tools. Adhesive spraying raises environmental health and safety concerns. Elasto Proxy can fabricate spall liners such as spall blankets that attach with hook-and-loop (Velcro) fasteners that provide high tensile strength and high shear strength.
Meet Elasto Proxy at CANSEC 2017
For more information about spall liners from Elasto Proxy, please contact us. If you plan to attend CANSEC 2017, visit us in Booth 1010. From May 31 to June 1, we’ll be showcasing samples of our military products at the EY Centre in Ottawa.