Simultaneous measurement method of both shock state and stress profile in polymers in 1 GPa stress

A new procedure of recording both Hugoniot parameters and stress profile is proposed to study shock characteristics of polymers in 1 GPa stress region. The assembly consists of an in-material polyvinylidene fluoride (PVDF) stress gauge element and an optical prism pin. The PVDF gauge records the shock wave stress profile, while the prism pin records the arrival of shock front at the free surface of the target. Argon laser beam is focused onto the bottom face of the prism pin placed on the free surface so as to satisfy the condition of total internal reflection. Shock velocity can be estimated from the time difference of two signals, the PVDF gauge and the prism pin. The Hugoniot state can be calculated by the shock velocity and the projectile velocity regardless of the stress profile obtained by the PVDF gauge. A typical result for polytetrafluoroethylene (PTFE) specimen is shown with the impact velocity of PTFE flyer of 295 m/s. The obtained Hugoniot point coincides very well with the published data. Pre...