On the impact and penetration of transparent targets

There is considerable interest in the performance of materials during impac t. The usual approach involves the application of an individual technique, such as flash X-ray. We present a new method using high-speed photography t o image simultaneously the penetration behaviour and the in-plane strains a t the rear surface, obtained using a find-grid technique. The approach is i llustrated by analysis of the impact of a rod travelling at 540 m s(-1) aga inst a polymethylmechacrylate (PMMA) block. Quantitative information is pre sented on the shapes and the volumes of fragmented material and the displac ements of the rear surface from initial impact to full penetration. These d ata should stimulate mathematical modellers using hydrocode methods. The te chniques have general applicability to any isotropic material.