Personnel Protection Armor Strength Enhancement by Nested Structures

The Armed Forces of Ukraine pay great attention to the development of personnel protection armor. However, despite the availability of protective equipment, the practice of warfare shows that the tasks of protecting military personnel are not fully resolved. The task of developing protective structures against bullets and shrapnel remains urgent. The analysis of scientific and technical information showed that the processes that occur during the impact interaction of elements of mechanical systems have not been fully studied, and the development of means to protect against kinetic damage has not been fully covered in scientific papers. The process of interaction between the impactor and the protective barrier may change if nested structures are used as a protective barrier. The possibility of developing a new method for increasing the strength of armor protection by using nested structures (bullet–cylinder) is investigated. A new analytical dependence for determining the depth of penetration of a bullet into a cylinder is obtained. The novelty of the analytical dependence lies in the absence in the scientific literature of a mathematical model of bullet penetration into a cylinder whose inner diameter is smaller than the outer diameter of the bullet, taking into account the effective friction coefficient between the bullet and the inner surface of the cylinder, and the fact that the depth of penetration of a bullet into a cylinder can be equal to the length of the bullet, or be greater or less than it. On the basis of the proposed analytical dependence for determining the depth of penetration of a bullet into a cylinder, the dependences of the depth of penetration of a bullet into a cylinder on the value of tension (between the bullet and the cylinder) and the thickness of the cylinder are constructed. The research results indicate the fundamental possibility of reducing the depth of penetration of a bullet by using nested structures.