As we all know, soldiers wear helmets not in the real sense of bulletproof, but to prevent bomb shrapnel from being carried on the battlefield. Secondly, with the development of military technology, modern soldiers helmets are equipped with a single-man combat system. The body armor can only effectively reduce the kinetic energy of the bullet, offset some of the bullet power, if you want to protect the bulletproof vest from the rifle bullet, you need to pad the body armor on the basis of the lining. You know, the body armor is mainly made of high-energy fiber braids, and then by multi-layer overlay, the working principle is actually somewhat similar to non-Newtonian fluid. When the body armor is hit by a bullet, the fiber force is stretched. When the bullet is more powerful, reaching the maximum force of the fiber, it will produce deformation. And if the bullet is less powerful, in the scope of the bulletproof vest, the bullet will be intercepted. Thus, even if the body armor can effectively resist bullets, but in the work of the body will be a certain degree of damage, but only to minimize the damage. In other words, in general, we use body armor in the process, in order to avoid unnecessary injury or pad the liner. Although helmets work differently than body armor, they are all for one purpose. Although modern soldier helmets also use the fiber material of body armor, the actual effect is not too great. Be aware that under the powerful kinetic energy of a bullet, the soldier's head is bound to suffer great damage, although the helmet will not be broken. And we all know that the head is the most vulnerable part of the human body, if the use of body armor material alone to make helmets, what will happen!