Two dimensional infrared resolution of shear bands formed during low velocity impacts of NaCl crystals using fast infrared detectors

摘要

NaCl crystals were subjected to low velocity impacts provided by a drop weight impact machine. The shear bands were imaged with the use of arrays of fast responding infrared detectors. The detectors monitored the amount of energy given off as infrared photons by the impacted crystalline solid. The main emphasis of this study was the real time observance of the shear band formation during the impact. The signal was recorded over the duration of the impact, heating of the solid during its crushing, and the relaxation of the crystal. These crushing processes occurred over a 40–100 mgr;s timescale. Rapid infrared photons corresponding to shear banding were recorded on a 30–90 ns timescale.