In the presented work, the author describes a new diagnostic method of ballistic resistance of multi– layered shields. The proper ballistic energy absorbed by the shield is introduced in the form V²_BL[R] according to Recht’s and Ipson’s method, and V²_BL[Z] according to author’s method. The kinetic energy of the bullet m_p · V²_p/2 and the momentum of force I are transferred to the shield and the dynamometer of ballistic pendulum. They are used to determine the proper energy V²_BL[Z] and ballistic thickness h_BL of the shield. The procedure can be widened onto the absorption of the energy by individual layers of the shield, where: A^Hn_an,bn – the effect of n – interlayer on proper energy absorbed by the shield. The effectiveness of the used methods is expressed by average effectiveness coefficient β_s of proper energy absorbed by the shield V²_BL as well as by average mass coefficients α²_s . The ballistic shields can be composed of different grades of metal layers and interlayer areas with well-chosen ballistic proprieties.

The maximization of interlayer effectiveness N_n[R] and N_n[Z] as well as relative mass effectiveness M_s[R] and M_s[Z] leads to optimum conditions of selection of multi–layered shields structures.

In the presented work, the author introduces the ballistic energy absorbed by the shield m_pV²_BL/2 to elaborate the results of firing on homogeneous plates and multi – layered constructional shields. The introduced criterion V²_BL is used to determine ballistic thickness h_BL and ballistic velocity V_BL under normal firing 7.62 mm ŁPS bullets.

The experimental tests were performed on an unified test stand to investigate ballistic resistance of materials in field conditions. The stand was developed at the Naval University of Gdynia and then patented. The design of this test stand was based on the construction of ballistic pendulum arranged for measuring: the impact forces, the turn angle of ballistic pendulum φ, initial and residual velocities of the bullet. All the measurement data were transmitted to a digital oscilloscope and personal computer. The energy absorbed by the shield was subject to further analysis of V²_BL[R] according to Recht’s and Ipson’s method and of V²_BL[Z] according to author’s method. The verification of the above-mentioned dependences was based on the results of the tests. The ballistic velocities V_BL[R] and V_BL[R] of the steel and steel – aluminium alloy shields with air interlayer thicknesses of 0, 6, 12 mm were approximately equal, however, they were quite different for aluminium alloy multi – layered shields, according to the results of firing 7.62 mm ŁPS bullets. These properties were confirmed by the average mass coefficients α²_s and average effectiveness coefficients β_s of the V²_BL for the tested methods.

In this work, the author presents experimental verification of numerical simulation of projectile impact on constructional shields. The experimental tests were performed at a unified test stand to investigate ballistic resistance of materials in field conditions. The stand was developed at the Polish Naval Academy in Gdynia, and then patented. The design of this test stand was based on construction of a ballistic pendulum, fitted to measure: impact force, turn angle of the ballistic pendulum χ, impact velocity and residual velocity of the projectile. All the measurement data were transmitted to a digital oscilloscope and a personal computer. The ballistic velocity of

the shield of V_BL[R] – defined according to Recht’s and Ipson’s method, was compared with V_BL[Z] and V_BL[Z1] – determined according to the author’s method. Verification of numerically simulated ballistic velocity V_RO versus the before-mentioned velocity

was carried out at the 10GHMBA-E620T steel shields impacted by 12.7 mm type B-32 projectiles. The introduced method can be used for determining ballistic thickness h_BL and ballistic velocity V_BL for both homogeneous plates as well as multi-layered constructional shields.