Avinadav C, Ashuach Y, Kreif R
Rafael Advanced Defense Systems, P.O. Box 2250, 31021 Haifa, Israel.
Rev Sci Instrum. 2011 Jul;82(7):073908. doi: 10.1063/1.3615243.
A new experimental approach of the Kolsky bar system using optical interferometry is presented for determination of dynamic behavior of materials. Conventional measurements in the Kolsky bar system are based on recording the strain histories on the incident and transmitter bars with two strain gauges, and require good adhesion between the gauge and the bar. We suggest an alternative approach, based on measuring the actual velocities of the bars by using fiber-based velocity interferometry. Two fiber focusers illuminate the bars at a small angle and collect reflected Doppler-shifted light, which is interfered with a reference beam. Velocities are calculated from short-time Fourier transform and phase-based analysis, and the dynamic stress-strain curve is derived directly from the measured velocity traces. We demonstrate that the results coincide with those obtained by conventional strain gauge measurements. The new method is non-intervening and thus not affected by bar impacts, making it more robust and reliable than strain gauges.
提出了一种利用光学干涉测量法的新型科尔斯基杆系统实验方法，用于测定材料的动态行为。科尔斯基杆系统中的传统测量基于用两个应变片记录入射杆和透射杆上的应变历史，并且要求应变片与杆之间有良好的附着力。我们提出了一种替代方法，基于使用基于光纤的速度干涉测量法测量杆的实际速度。两个光纤聚焦器以小角度照射杆并收集反射的多普勒频移光，该光与参考光束发生干涉。通过短时傅里叶变换和基于相位的分析来计算速度，并直接从测量的速度迹线推导出动态应力-应变曲线。我们证明结果与通过传统应变片测量获得的结果一致。新方法是非侵入性的，因此不受杆撞击的影响，使其比应变片更稳健、更可靠。
