Abstract
The term shock wave in solids has been defined only mathematically so far. However, the modern information digital technology enable us to measure thickness and rise time on the wavefront that varies very steeply similar to the shock wave. In this study, the thickness or the rise time on the wavefront is measured using a plate impact test at an impact velocity ca. 600 m/s for a glassy polymer such as PMMA or PC, and yet it is difficult to ensure that the thickness or the rise time is infinitesimal. On the other hand, the longitudinal wave velocity of the wavefront measured using PVDF gauges and also using a modified UWSS (Unsteady Wave Sensing System) is more than the wave velocity associated with corresponding stress. Moreover, the stress-strain relationships on the wavefront are along Rayleigh lines. Thus, this wavefront is considered physically as the shock wavefront.
