Influence of serrated configuration on transverse overload of the projectile penetrating with small attack angle

In the process of deep penetration of the earth penetration weapon (EPW) attacking the underground target, the non-ideal penetration attitude with initial attack angle is inevitable, which will introduce transverse overload with large peak value for the earth penetrator. However, the excessive overload peak value could damage some important components of the earth-penetrating projectile and reduce the penetration efficiency of the projectile. Therefore, it is necessary to study the methodology of reducing the transverse overload peak value of the earth-penetrating projectile. However, the previous research on the earth-penetrating projectile seldom takes into account the influence of transverse overload and it is difficult to effectively reduce the transverse overload. In order to overcome this problem, a new type of the earth-penetrating projectile with serrated configuration and the special shedding effect and mechanism of transverse overload were studied by numerical simulation method when penetrating the concrete target at the non-zero attack angle. The influences of the initial attack angle and the coefficient of the center of mass of projectile were studied, and the motion, contact force, contact moment and contact area of the projectile were analyzed by using conventional smooth projectile as comparison. The results show that for small initial attack angles of 1°, 2° and 3°, the peak value of transverse overload of the serrated projectile is reduced by about 30.6%, 5.2% and 11.3% compared to the smooth projectile, but the peak value of contact moment, pulse width and deflection angle are increased. The research reveals the mechanical mechanism to reduce transverse overload: the serrated body of the projectile reduces the contact area between the projectile and the target, and the transverse contact force is mainly concentrated on the upper surface of the right serrated parts of the first two serrated grooves near the head of the projectile; the transverse contact force between the serrated body and the target decreases, while the transverse contact force between the non-serrated parts (mainly the head of the projectile) and the target increases. Therefore, these two parts of the projectile are competed and control the reduction effects of the transverse overload of the whole projectile in the process of deep penetration with initial attack angle. When the ballistic deflection of the serrated projectile is suppressed by means of certain optimization of structural design, the transverse overload shedding efficiency of the serrated projectile can be effectively improved.