Abstract
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.
Highlights
The thermo-mechanical behavior of composite material on mesoscale and microscale is dependent on the microstructure and local morphological features
polymer-bonded sugar (PBS) has been commonly used as a mock and inert surrogate to investigate the thermo-mechanical response of polymer-bonded explosive (PBX) under inert conditions and different loading conditions
Using equation (2), the effective shock viscosity of 16.43 ± 1.26 Pa-s is estimated at a strain rate of 107/s
Summary
The thermo-mechanical behavior of composite material on mesoscale and microscale is dependent on the microstructure and local morphological features. The high strain rate material response in microscale domains such as interfaces and different components in the composite material can be significantly different from the overall behavior of microstructure. Such behavior at different scales requires significant attention as the overall behavior is governed by the local mechanical, thermal, and chemical properties of the components and can significantly change the overall response to impact loading. We extended the capability of our previous work [1, 2] to measure shock behavior in microscale with nanosecond time resolution This method provides shock measurements in a non-contact and non-invasive manner without altering the chemistry and mechanics of the microstructure. Under the assumptions of planar shock conditions, the local strain rate and shock viscosity can be estimated based on equations (1) and (2) respectively [5]
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