Bulletproof principle

- Jul 20, 2019-

On the Korean battlefield, the U.S. military was equipped with M52 nylon body armor, blocking 70% of the direct hit of the dead, reducing the death rate of the chest and abdomen by 65%, and reducing the overall reduction rate by 15%.

In 1983, it was reported that five United States Marines were patrolling the streets of Beirut when they were suddenly attacked by a grenade, which exploded near them in their vicinity, with no injuries or injuries, only minor upper and lower limbs. The above statistics and reports strongly prove the protective effect and protective effectiveness of bulletproof clothing. So what's the secret of bulletproof vests?

How does the "hard armor" protect against bullets? After the early 70's, the use of metal, bulletproof ceramics, high-performance composite panels and non-metallic and metal or ceramic composite sheet and other hard materials bulletproof jacket, its bullet-proof mechanism is mainly in the bomb hit material fragmentation, cracks, punching and multi-layer composite plate layering and other phenomena, so as to absorb a large number of projectiles impact energy. When the hardness of the material exceeds the impact energy of the projectile, the shooting rebound phenomenon can occur without running through.

How does "soft armor" protect against bullets?

If the bulletproof jacket using high-performance fibers such as bulletproof nylon, aramid fiber, acrylic fiber and other soft materials, its bullet mechanism is mainly the shooting bullet fiber stretching and shearing fiber, at the same time, the fiber will impact can be transmitted to the area outside the impact point, energy is absorbed and the piece or warhead wrapped in the bulletproof layer. Experiments show that there are five ways to absorb energy in soft body armor: 1. Stretch deformation of fabric: the deformation of the bullet's incoming direction and the stretch deformation of the near by the incident point; 3. Heat: The energy of a bullet is radiated by friction by heat; 4. Sound energy: the energy consumed by the sound of a bullet hitting the bulletproof layer; and 5. the deformation of the bullet body.

How does the composite "armor" protect against bullets? It should be noted that this soft body armor, known as "soft armor", does not prevent direct-shooting projectiles with sufficient energy or heavy weight from invading the human body, so it is necessary to attach hard inserts, ceramic plates or composite plates, i.e. soft and hard materials, to combine the two protective mechanisms, In order to play a protective effect on the human body to achieve the purpose of bulletproof. The bullet-proof mechanism of this soft-hard composite body armor is this: when the bullet hits the body armor, first with the bulletproof plate of the first line of defense in the body armor or reinforced ceramic plate or composite plate contact, in this contact moment, the bullet and hard bulletproof material may produce deformation and fracture, so, consume most of the bullet energy. The soft bulletproof material acts as a second line of defense, absorbing and spreading the energy of the rest of the bullet and acting as a buffer to prevent and reduce the perient damage.

How do bulletproof vests? Due to the irregular shape of the pieces and shrapnel produced when the grenade, bomb exploded, the edges are sharp, small in size and light in mass, and they are not deformed after hitting the bulletproof material, especially the soft bulletproof material, and are dense, when the pieces are cut, stretched and broken by the fibers of the bulletproof fabric The break also causes the interaction between the internal fibers of the fabric and the different layers of the fabric, causing the fabric to change the whole body and consuming its own energy when the piece destroys the body armor. At the same time, the chip also has a small amount of energy through friction into heat energy, through impact into sound energy.

The body armor then prevented the grenade and bomb from being damaged to the chest and abdomen and even the neck (high-necked body armor).