鋼鈑の防彈効率と物理的性質

Abstract

The purpose of the present investigation was to obtain the relation between the absorbing energy of shiled plates in resisting the penetration by a rifle bullet and the physical properties of the material of the plate. For the purpose mentioned above, we obtained at first experimentally the so-called “characteristic curves” of the shielding efficiency of the various metals under the conditions of three different initial velocities of the bullet, and secondly, based on the results of the above-mentioned experiments, the following relation was deduced v2=v1-2/mv1(At2+Bt4), where v1, v2, m and t denote the initial and residual velocity of the bullet, the mass of the bullet and the thickness of the shield plate respectively. Next, using the above-mentioned experimental results, we arrived at the following results that A and B, the coefficients of the resistance, depend respectively on the hardness (H), the internal viscosity (μ) and also on the thermal diffusivity (K) of the metal of the shield plate, connected with each other by the following expression where y=A or B, x=μH/K; a, b are the constants depending merely on the initial velocity of the bullet.