EFFECT OF THE PMMA SACRIFICIAL LAYER ON THE FAILURE MECHANISM OF PC AND STEEL BACK PLATES SUBJECTED TO IMPACT AT VARYING LOCATIONS FROM THE CLAMPED EDGE

摘要

In the present work circular PC and steel armor plates were provided with a sacrificial layer of PMMA that absorbed some of the kinetic energy of a low velocity spherical projectile before striking the PC back plate. The brittle failure of PMMA and the ductile damage mechanism of PC and steel plates were investigated by varying the impact locations on the layered armor plates. The impact event of layered target was simulated using LSDYNA. Numerical results agreed well with the experimental evidence. A gradual increase in the energy absorbing pattern was observed for impact locations close to the clamped edge of the layered target plates but for monolithic PC armor a decrease in the energy absorption was observed. Though the damage suffered by the target plates for impact locations away from the clamped edge was within acceptable ballistic limit, the impact near the clamped edge caused severe plastic damage to the armor plate. The adverse effect of PMMA brittle failure upon the PC back plate is reported where the residual strength of the PC plate was severely compromised.