What is bulletproof material? Where is it used?
The most common hard armor will use ceramic plates as baffles, but ceramic shatters on impact and loses its energy for sustained combat. Most metal plate armor has the same problem of bullets flaking off on impact. These fragments can cause injury to the person wearing the armor With the development of lightweight combat technologies such as aircraft and amphibious vehicles, and the need to increase the mobility of ground forces, there is a demand for ballistic materials that continue to reduce the weight of armor while improving ballistic performance.
Ballistic shields are available in a variety of types and grades. These materials are used to protect glass, vehicle armor, body armor and shields. Laminated plastic sheets offer a wide range of protection, from certified sealed glass to tertiary ballistic materials. Ballistic materials are usually rigid, but can also be soft. They can be complex, such as Kevlar, UHMWPE, Lexan or carbon fiber composites, or simple, such as aluminum, steel, titanium or other alloys.

How does foam metal work on body armor?
Foam metal has been proven to trap bullet fragments and protect you from any secondary damage. Most military body armor uses a Kevlar-like material as a back layer, which is usually rated III-A and will stop handgun rounds on its own. Soft armor stops bullets by dissipating energy, and since most handgun bullets aren’t as sharp as rifle bullets, you just need to slow them down so they don’t penetrate your skin. The foam metal layer is the body armor’s shock absorber for the higher energy bullets that require hard armor to stop. The expanding structure of the foam metal transfers collision energy far less efficiently than solid components. In the area of impact, the foam easily conforms to the impacting object. This plastic deformation locally absorbs mechanical energy. In either case, very little of the collision energy is absorbed by the solid. Some people also choose to add a third layer behind the soft armor, which is called a trauma pad. This is a pad made up of layers of non-Newtonian fluid and padding. It further mitigates the impact of bullet impact on the wearer.