We can know that bulletproof vest and stab-resistant vest belong to the category of protective equipment, they seem to be very similar, but they are aimed at different fields and deal with different Equipment researched out of the situation. Why body armor can be bulletproof, but not stab and knife-proof; and body armor can prevent swords and slashes, why are swords and stabs Can't defend against bullets? Isn't body armor not bulletproof and stab-proof and cut-proof?
The answer is yes, that is, body armor can be bulletproof and stab-resistant, this is only a new bullet proof equipment in recent years, "bullet-proof and stab-resistant clothing" is also called bullet-proof and stab-resistant vest.
Here I am here to answer your questions. Why a single body armor can only be bullet-proof but not stab-proof? The specific questions should start from the following aspects:
The main difference between full bulletproof suit and stab-resistant vests is that they have different functional protection objects. The former is mainly used for the protection of bullets, while the latter is mainly used for the protection of knives and sharp-edged instruments. Bulletproof vests and stab-proof vests have different protection objects, so the principles and structures used in their design are also different, so the two cannot be mixed.
Ordinary body armor is made of Kevlar material. When the bullet hits the body armor, the extremely tough Kevlar fiber will transmit the kinetic energy of the bullet to the entire body armor, so that the bulletproof effect can be achieved. In other words, the principle of body armor is actually to share the impact kinetic energy of the warhead to each Kevlar fiber, so the body armor is completely scrapped after one shot. But what the tool produces is shear stress, the direction of the force is perpendicular to the fiber material, and the energy density of the tool tip is much higher than that of the bullet. Anyone who has studied materials knows that fiber material has the worst resistance to vertical shear stress. , It can even be said that there is no effect, so for the knives, the body armor had no choice but to sigh.
Because the impact mechanism of high-speed bullets on body armor is different from that of sharp weapons, the energy dispersion of the former mainly disperses or consumes energy through warhead deformation, fiber breakage and shock wave propagation, while the knife pierces the body armor. Mainly relying on the principle of shearing, the energy dispersion range is relatively narrow, especially the bayonet with a sharp head is more difficult to prevent. Therefore, the body armor is made of high-strength fiber weaving in multiple layers according to specific rules, and the stab-proof garment is made of fiber and mixed steel wire.
Understand the above three points, it is not difficult to understand why single bulletproof vests and stab-resistant clothing can only be used in a targeted manner. Some people say that if you want bullet-proof and stab-resistant, you can just get one and wear them all on your body to achieve the effect of bulletproof and stab-proof? I am sure that this is indeed bulletproof and stab-resistant, but the wearer can work hard. Not to mention the weight of a body armor is 4-5KG, it will affect the activities of the human body if it is worn on the body, plus a stab-resistant suit. It really means that the protection is in place and the movement is restricted. If you wear it on your body for less than an hour, you will not be able to take it off. For this reason, bullet-proof and stab-proof clothing solves this problem well, and one piece of clothing is done.
Bullet-proof and stab-resistant clothing is mainly divided into two types, one is: bullet-proof Kevlar layer + bulletproof metal sheet; the other is: bullet-proof Kevlar layer + stab-resistant felt or impregnated film called soft bullet-proof stab-resistant clothing. Soft bullet-proof stab-proof vest. After dipping, the woven fabric or non-weft cloth with bullet-proof ability will make the overall material stiff and harder. It can also have the function of stab-proof, and the machine with good elasticity performance without treatment. The combination of woven fabric or non-weft fabric can achieve a good double defense effect, while reducing the thickness and improving the comfort of wearing.