No abstract

Quantitative information regarding the local behavior of interfaces in an inhomogeneous material during shock loading is limited due to challenges associated with time and spatial resolution. This paper reports the development of a novel method for in-situ measurement of the thermo-mechanical response of polymer bonded sugar composite where measurements are performed during propagagtion of shock wave in sucrose crystal through polydimethylsiloxane binder. The time-resolved measurements were performed with 5 ns resolution providing an estimation on local pressure, temperature, strain rate, and local shock viscosity. The experiments were performed at two different impact velocities to induce shock pressure of 4.26 GPa and 2.22 GPa and strain rate greater than 106/s. The results show the solid to the liquid phase transition of sucrose under shock compression. The results are discussed with the help of fractography analyses of sucrose crystal in order to obtain insights into the underlying heat generation mechanism.

In this article, the dynamic response of a heterogeneous microstructure of polymer bonded composite was analyzed to a short duration shock pulse. The composite microstructure studied is a polymerbonded sugar (PBS) with single-crystal sucrose embedded inside the polydimethylsiloxane binder. The shock pulse was created by the impact of the aluminum disk at high speeds using a laser-based projectile launch system. The mechanical response on the microscale domain was measured using ultrafast time-resolved Raman spectroscopy. The in-situ analysis of the change in Raman spectra from PBS during shock compression was captured in the time domain using a streak camera. The results show a steeply rising shock front after the impact where the shock pressure rise time was estimated from the time-resolved Raman spectra. The viscoplastic behavior in the local microscale domain was characterized by quantifying effective shock viscosity measured in the vicinity of the crystal-binder interface.