Shock response of a glass-fiber-reinforced polymer composite

The present work describes the compression and release response of a glass-fiber-reinforced polyester composite (GRP) under shock loading to 20 GPa. Shock experiments in GRP were performed at Sandia National Laboratories and the US Army Research Laboratory. GRP is a heterogeneous material. The diagnostic measurements fluctuate beyond the precision of the experimental measurements but they do permit determination of an average response of the material at the end state. These experiments show that: (i) GRP deforms elastically in compression to at least 1.3 GPa; (ii) the deformation coordinates of shocked and re-shocked GRP lie on the deformation locus of initially shocked GRP to 4.3 GPa; (iii) and the release path of GRP shocked to varying magnitudes of stresses indicate that the GRP expands such that its density when stresses are released in the range of 3–5 GPa from a peak compressive stress of 9 GPa and above is lower than the initial density of GRP. Possible reasons for the observed lower density remain to be investigated.