Abstract: The experiment of stretched rod copper explosion formed projectile (EFP) formed by the shaped charge penetrating into main target add-on typical explosive reactive armor（ERA）with different oblique angle were conducted to reveal the effect of sandwich ERA on penetration efficiency of EFP. The pulsed X-ray photographs of the interaction between ERA and EFP were obtained by flash X-ray experiment, together with residual depth of penetration (RDOP) of residual EFP. The results show that RDOP has a nonlinear decreasing tendency as oblique angle raises. The drop of penetration depth of EFP passing through ERA exponentially increases with ERA oblique angle. When the oblique angles of ERA are 0° and 30°, RDOP and drop of penetration depth keep stabile. But when it grows from 30° to 60°, RDOP declines from 0.50 D to 0.19 D, and the drop of penetration depth grows rapidly from 41% to 77%. On the other hand, the increment of layer thickness results in a heavier reduction in RDOP and the increase in the drop of penetration depth. ERA with 0.027 D layer thickness makes the drop of penetration depth higher 8% on average than it with 0.018 D. The reason for RDOP reduction is analyzed for researching the mechanism of action of EFP and ERA. Key

Key words: explosivereactivearmor, explosionformedprojectile, residualdepthofpenetration, dropofpenetrationdepth