The effect of specimen thickness on the shock propagation along the in-fibre direction of an aerospace-grade CFRP laminate

In-fibre measurements of the Hugoniot have been carried out on a carbon fibre-reinforced polymer composite. For this material, we have shown at high shock stresses, a two component wave was formed consisting of a fast moving ramped portion and a slower moving shock wave. Changing the thickness of test specimen for a given shock stress resulted in a change in the magnitude and duration of the ramped portion of the wave front. As the shock stress imparted to the target was reduced, or the thickness of the target was increased, the steep shock wave in the rear surface gauge was no longer apparent. Instead a relatively slow rising wave was measured. Consequently, to establish a Hugoniot at lower shock stress levels, relatively thin specimens of target material are required.