激光多普勒测速仪应用于纳秒激光冲击过程的模拟和实验研究  

Numerical and experimental investigations on application of Photon Doppler Velocimetry in nanosecond laser-shock process

作　　者：夏苑桃 蔡洋 XIA Yuantao;CAI Yang(The Peac Institute of Multiscale Sciences,Chengdu 610031,Sichuan,China)

机构地区：[1]顶峰多尺度科学研究所,四川成都630031

出　　处：《实验力学》2020年第6期994-1002,共9页Journal of Experimental Mechanics

基　　金：国家自然科学基金(11627901)及挑战计划(TZ2018001)资助。

摘　　要：为探索激光多普勒测速仪(PDV)探测效果的影响因素,并检验其用于纳秒激光冲击实验的可行性,本文依靠自主研发的PDV模拟方法以及纳秒激光实验平台,对PDV在稳态及动态下的测量精度进行了定量的测量和分析。稳态的模拟和实验结果显示,改善噪信比以及增加采样率能提高速度信号的质量,而增加时间窗口的长度虽能降低速度信号的不确定度,但是牺牲了部分时间分辨能力。而动态的模拟和实验结果则显示,短时间窗口在速度剧烈变化的情况下(如峰值)拥有更好的表现,而长时间窗口在速度变化较平缓的情况下能发挥出更好的效果。定量的误差分析表明,选取合适的数据解读方法,PDV能够对纳秒级的激光冲击实验进行较为精确的测量。此外,本文的模拟方法能较为精确地预测PDV的实际表现,并为其指明了改进的方法:降低噪信比、增加采样率、根据实际的需求和数据的类型选取合理的时间窗口。Simulations and experiments of steady state and dynamic loading are conducted to evaluate the influence factors of Photon Doppler Velocimetry(PDV)and its applications to nanosecond laser-shock process.The results of steady state simulations and experiments indicate that improving signal noise ratio and increasing sampling rate can promote the quality of velocity results.Increasing the time window can also reduce the uncertainty of velocity at the expense of decreasing the temporal resolution.The simulation and experiment results of dynamic loadings indicate that small time windows lead to better performance at acute velocity changes(e.g.,peaks).On the contrary,large time windows result in better precisions when velocity changes slowly.Through quantitative error analysis,PDV is proved to be able to obtain accurate measurement in nanosecond laser-shock experiments with proper data analysis method.Besides,the simulation methods accurately predict real experiments and propose improving methods for PDV:decrease noise signal ratio,increase sampling rate and choose proper time window according to the demands and data types.

关 键 词：激光多普勒测速仪 激光冲击波 纳秒 

分 类 号：O39[理学—工程力学]