Principle of bulletproof glass How is bulletproof glass made?

Bulletproof glass, I believe many people have heard of it, but they don't know much about it. Bulletproof glass originated in Europe and America. In recent years, the production capacity of bullet-proof glass enterprises in China has expanded rapidly, which is equivalent to that of the United States, Germany and other countries. With the gradual transfer of international bulletproof glass industry to China and the improvement of R&D and production capacity of local enterprises in China, China will become one of the most important bulletproof glass production bases in the world in the next few years. Next, let's look at the principle of bulletproof glass.

What is bulletproof glass?

Bullet-proof glass is a composite material made of glass (or plexiglass) and high-quality engineering plastics through special processing. It is usually a transparent material and usually includes polycarbonate fiber layers sandwiched between ordinary glass layers.

Bulletproof glass principle

In bomb attack and accidental explosion, explosion-proof glass can minimize the direct damage caused by the ultra-high load of explosion shock wave and high-speed flying glass fragments, and reduce the repair cost of the attacked facilities or facilities around the explosion center. Explosion-proof glass is still impermeable when the load formed by the energy of explosion shock wave increases several times or even dozens of times sharply, and the glass retention value RET≈ 1. However, once a single piece of glass (including float glass, tempered glass and insulating glass) is broken, as long as it slightly exceeds the critical crushing pressure, RET will soon drop below 0.3, and glass fragments will be scattered, leading to penetration failure.

Explosion-proof function of bulletproof glass

Worldwide, bomb attacks (including car bombs and suicide bombings) and terrorist threats are on the rise. The Marriott Hotel in Indonesia is a typical event. With the increase of bomb power, people's life safety and property are seriously threatened. According to the analysis of safety experts and related data, the scattering of glass and the splashing of fragments are the main reasons for personal injuries. In the terrorist explosion of bombs, 75% of injuries are related to glass, which means that if explosion-proof glass is used, the degree of injuries can be reduced by 75%. If the glass of all buildings can be kept intact in the frame when the explosion occurs, then the shock wave energy will not enter the room and the indoor items will not be damaged; High-speed debris will not enter the interior of the building, nor will it fall to the ground to cause injury.

What is bulletproof glass made of?

Bullet-proof glass is actually made of multiple pieces of glass or high-strength organic plates bonded together with transparent adhesive materials. Generally, it has the following three-layer structure:

① Load-bearing layer: this layer cracks first when it is impacted. Generally, glass with large thickness and high strength is used, which can destroy the warhead or change its shape, making it lose its forward ability.

② Transition layer: Generally, organic adhesive materials are used, which have strong adhesion and good light resistance, and can absorb part of impact energy and change the direction of bullets. Sandwich a very strong and transparent chemical film in laminated glass. This not only can effectively prevent bullets from shooting, but also has the properties of surge impact resistance, explosion resistance, earthquake resistance and no cracking after impact.

③ Safety protection layer: This layer is made of high-strength glass or high-strength transparent organic material, which has good elasticity and toughness, can absorb most impact energy, and ensures that bullets cannot pass through this layer.

The most important performance index of bulletproof glass is bulletproof ability. The index of bulletproof ability is measured from two aspects, on the one hand, the safety protection ability, on the other hand, the killing ability of the protected guns.