Shockless and shock wave compression of ballistic gel to 1.3 GPa

Abstract

Plate impact experiments were conducted to determine the dynamic compression response of two ballistic gel concentrations (10 wt. % and 20 wt. %) subjected to uniaxial strain loading to 1.3 GPa. Shockless and shock wave compression of gel samples was achieved through flyer plate impacts on fused silica and z-cut quartz plates, respectively, placed ahead of the samples. Laser interferometry was used to measure the input compression wave profile and the propagated wave profile in each experiment. Using established wave analysis methods, the longitudinal stress-density compression results were obtained for each type of loading. The 20 wt. % gel showed a stiffer compression response than the 10 wt. % gel; the difference corresponded to the gel properties at ambient conditions. The shockless experiments provided both the loading paths and the peak states for this type of loading. Although the differences were small, the peak states achieved in shockless compression were below the shock wave (Hugoniot) data for both gel concentrations. The shockless compression results presented here are the first such results on gels, and provide the gel response at loading rates that are intermediate between the shock wave response and lower loading rate response. As such, they are expected to be useful for incorporating the dynamic compression response of gels in numerical simulations of impact phenomena.