LEADEROF

CHINESE POLICE EQUIPMENT MANUFACTURER
Jiangsu Anhua Police Equipment Manufacturing Co.,Ltd(Be established in 1988 )
Mechanism and influencing factors of bullet proof vests
time2014-12-11 04:42 read times

There are two mechanism fundamentally of bullet proof vests: First, after the formation of the projectile fragmentation fragments bounce;  second, through the bulletproof material dispel kinetic warhead.

In the twenties and thirties,in USA the first body armor was developed by the clothes even in the solid lap steel to provide protection. This body armor and bulletproof later similar hardware that is by bullet or shrapnel bounce, or make the bullet fragments to break down their energy consumption and the role played bulletproof. High performance fiber as the main material of software bulletproof vests, bulletproof mechanism which places the latter based, namely the use of high-strength fiber as raw material fabric "grab" a bullet or shrapnel bullet to achieve the purpose. Research shows that the way software bulletproof vests to absorb energy in the following five categories:

(1) fabric deformation: the deformation of the incident and the incident direction of the bullet points, including the area near the tensile deformation;
(2) destruction of the fabric include: fibrillated fiber fracture, disintegration and dissolution of the yarn structure of the fabric structure of the fibers;
(3) heat energy: energy through friction way to distribute heat;
(4) sound energy: ballistic projectile impact sound energy emitted consumed layer
(5) elastomers.

In order to improve the capacity and developed bulletproof soft and hard composite body armor, bulletproof mechanism which can be summed up with the "carrot and stick." When the bullet hit body armor, the first action is to take place with a hard material such as steel or armor-reinforced ceramic materials. In this moment of contact process, the bullet-proof material and rigid deformation or fracture can happen, most of the energy consumed bullets. High-strength fabric liner as body armor and a second line of defense, absorption and diffusion of energy remaining portion of the bullet and play the role of a buffer, so as to reduce the non-penetrating injury. In these two bulletproof during previous plays a major role in energy absorption, greatly reducing the penetration force of the projectile is bulletproof key.

Factors affecting bulletproof vests and bulletproof material performance can be considered from two aspects interact projectile (the bullet or shrapnel). Specifically on the radio, it's kinetic energy, shapes and materials is an important factor in determining its penetration power. Ordinary warheads, especially lead core or ordinary steel core bullet-proof material after exposure will deform. In this process, the bullet is consumed a considerable part of the kinetic energy, thus effectively reducing the penetration of bullets, is an important aspect of bullet energy absorption mechanism. As for the secondary shrapnel or bullet fragments generated when the bomb exploded, grenades and the like, the situation is significantly different. These shrapnel irregular shape, sharp edges, light weight, small size, in particular, after hitting soft bulletproof material bulletproof material deformation. In general, the speed of such debris is not high, but the large and dense. Soft body armor for key energy absorption that such debris: fragments cut, stretch and make bulletproof fabric yarn breakage, and make the interaction between the internal fabric of yarn and fabric between different levels, resulting in deformation of the fabric as a whole in the course of these pieces of external work, thereby consuming its own energy. In the above two types of body energy absorption process, there are a small part of the energy by friction (fiber / fiber, fiber / bullet) into heat, is converted to acoustic energy by the impact.

In order to meet the body armor bullet To maximize absorption and other requirements of the kinetic energy of the projectile, bulletproof material must have high strength, good toughness, high energy absorption capability of performance. Currently used for body armor, especially soft body armor material on both high performance fiber-based. These high-performance fibers with high strength and high modulus is an important feature. Some high-performance fibers such as carbon fibers or boron fibers or the like, although having a high strength, but because of poor flexibility, low work of fracture, it is difficult textile processing, as well as the reasons for higher prices, substantially does not apply to human body armor. Specifically, for ballistic fabric, its ballistic effect depends on the following aspects: fiber tensile strength, elongation at break and work of fracture of the fibers, the modulus of the fibers, the orientation of the fibers and the stress wave transmission speed, fiber fineness, set mode fiber, fiber weight per unit area, structure and surface characteristics of the yarn, fabric structure, the thickness of the fibrous web layer, network layer or layers and other fabric layers. For the impact of the fiber material, its performance depends on the speed of the fracture energy and stress wave fiber transmission. Stress wave diffusion request as soon as possible, but in the high-speed impact of fiber fracture energy should be increased as much as possible. Tensile fracture function material is a material resistant to external damage has energy, it is a tensile strength and elongation related functions. Thus, theoretically, the higher the tensile strength, elongation ability strong material, its potential energy absorption becomes. In practice, however, the material for the body armor does not allow excessive deformation, so the inevitable fiber for body armor while having a high ability to resist deformation, i.e. high modulus.
 

Bullet Proof Vest BPV-AH03