基于光纤镀膜探针的固体介质中应力波粒子速度测量技术

Measurement technology of stress wave particle velocity in solid medium based on optical fiber coated probe

  • 摘要: 粒子速度是分析固体介质中应力波传播规律的一个重要参数。结合激光多普勒效应和全光纤干涉测速系统,提出了一种基于光纤镀膜探针的固体介质中应力波粒子速度的测量方法。将光纤镀膜探针嵌入有机玻璃(PMMA)中,距爆心同一半径处,采用0.125 g TNT当量的微型炸药球作为爆炸源,进行填实爆炸产生应力波,通过采集光纤探针端面的运动信息,基于短时傅里叶变换的时频分析方法,解调出端面运动速度,进而反推出粒子速度。实验结果表明:不同光纤镀膜探针测得的速度分别为22.648 m/s、23.505 m/s,将反推的粒子速度与传统的圆环型电磁粒子速度计方法获取到的数据进行对比,两者的相对偏差低于5.00%,验证了光纤镀膜探针测量固体介质中应力波粒子速度的可行性。

     

    Abstract: Particle velocity is an important parameter for analyzing the propagation law of stress waves in a solid medium. Combining the laser Doppler effect and an all-fiber interferometric velocimetry system, a measurement method of stress wave particle velocity in solid medium based on fiber coated probe was proposed. The optical fiber coated probe was embedded in the polymethyl methacrylate (PMMA) at the same radius from the burst center, and the miniature explosive ball with 0.125 g TNT equivalent was used as the explosion source to fill in the center cavity and generate stress wave. Based on the time-frequency analysis method of the short-time Fourier transform, the velocity of the optical fiber end surface could be calculated from the collected signal, and then the medium particle velocity could be deduced. The experimental results show that the velocity of the data measured by different fiber coated probes is 22.648 m/s and 23.505 m/s, respectively. The relative difference between the resulting particle velocity and the data obtained by the traditional circular electromagnetic particle speedometer method is less than 5.00%, which indicates the feasibility of the proposed method.

     

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