In the present paper results of plate impact experiments conducted to understand the dynamic response of glass fiber reinforced plastics (GRP) are presented. The shock compression response of GRP was investigated because of its promising potential for use in future combat vehicle defense systems. The GRP laminates were provided by ARL, MD, and were made from S2 glass woven roving in Cycom 4102 polyester resin matrix with resin content 32＋/-2% by weight. The laminate plies were 0.68 mm thick. A multi-beam VALYN VISAR was used to obtain the particle velocity history at the rear surface of the target plate. These measured profiles were used to understand (a) dispersion and attenuation of shock-waves in GRP, (b) conditions under which dynamic deformation in GRP is reversible, and (c) the spall (delamination) strength of the GRP composite under compression and pressure-shear shock wave loading conditions. The experimental results indicate that the GRP deforms elastically up to 1.3 GPa. The shock front indicates an initial sharp rise in particle velocity followed by a distinct knee. The rise-time associated with the initial sharp rise is observed to decrease with an increase in impact velocity. The slope of the wave profile, following the knee, is observed to increase with an increase in impact speed. Moreover, the results indicate that the GRP shows almost no attenuation with propagation distance. This result is in contrast to the previous work reported in the literature on GRP that was conducted employing embedded PVDF gages. The results of the spall experiments indicate that even when the deformation of the GRP proceeds in an elastic manner, the decohesion strength of the plies under pure tensile loading can be very small. Also, it is observed that the presence of shear strain is detrimental to the delamination strength of the GRP.
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