IED attacks, landmines, and mortar fire aren't the only threats to military assets such as mine-resistant ambush protected (MRAP) vehicles. The big diesel engines that power these armored fighting machines generate large amounts of noise and heat. Military specifications limit the amount of noise exposure to occupants, and high heat from vehicle engines can damage components under the hood and make cab temperatures unbearable.
Acoustic and thermal insulation may not receive the attention of the latest weapons systems, but vehicle designers understand the damage that excessive heat and noise can cause. Along with vibration damping products such as shock absorbers and floor matting, military vehicles like the MRAP may also need impact-resistant insulation that's shrapnel-proof.
Sound Insulation and Heat Insulation
Protecting personnel and equipment is a complex task, so defense contractors need partners who understand all of their requirements and can even help design new products. Depending upon the application, technical may need sound insulation, heat insulation, or both.
Acoustic insulation is usually made of polyethylene or polyester foams that allow sound waves to bounce off. These lightweight, sound-dampening materials may also include a sound-absorbing barrier. Most acoustic insulation has an open cellular structure that permits the passage of air, a good insulator. Closed cell acoustic foams are used mainly in underwater applications rather than land vehicles.
Thermal insulation is designed to absorb heat from a vehicle's engine compartment and deflect heat away from the cab. Silicone, a durable synthetic resin, is often used because it resists high temperatures and provides acoustic insulation from high-decibel diesel engines. Self-extinguishing firestocks and custom composite insulation are also available.
Composite Panels and Civilian Applications
Thermal and acoustic insulation can be made of composite materials and formed into application-specific shapes and thicknesses. For example, thermal-proof panels made of ceramic fiber, polyurethane foam, and microcellular or silicone foam can provide heat shielding as high 1200° C in locomotives. By laminating multiple layers of insulating materials together, suppliers can build sandwich-like panels that are suitable for military or civilian applications.
Truckers also appreciate the benefits of high-quality insulation. Whether for long-haul trucking, construction site work, or local runs in a garbage truck, sound insulation is important. As with thermal insulation, sound insulating products can be color-matched to the vehicle. In commercial trucks, for example, a vinyl exterior may be applied to enhance the cab's appearance.