WEB Local Shock Viscosity Measurement in Composites using In-situ Time-Gated Raman Spectroscopy
Shock viscosity measurement for the material is important to characterize the dissipation mechanism for shock front to reach extreme pressures in a very short period. The shock pressure rise time in a material is correlated to the shock viscosity as a function of strain rate. In this work, a novel experimental setup based on nanosecond time-resolved Raman spectroscopy was used to measure in-situ stress rise due to impact from high-speed microsphere. The Raman spectroscopy was used in combination with a streak camera to obtain nanosecond resolved Raman spectra from a microscale domain to measure local pressure rise time. This technique provides an advantage over free surface velocity measurement techniques such as photon Doppler velocimetry or VISAR where a reflective surface is not available. This technique was used to measure local shock viscosity at the interface between octahydro-1,3,5,7-tetranitro-1,3,5,7-tetrazocine (HMX) and Hydroxyl-terminated polybutadiene (HTPB) binder at strain rates higher than 1e6/s.