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光纤激光干涉(PDV)是最近几年发展起来的一种新型测速技术,在某些领域已逐渐取代任意反射面测速(VISAR),但在低速且短瞬时快速变化的质点速度测量方法和数据处理技术还不成熟.本文针对激光冲击强化过程中靶材自由表面速度这一具有典型短瞬时、速度剧烈波动、速率变化大等特征的非平稳信号进行PDV测量,比较了短时傅里叶变换和连续小波变换的处理结果.研究表明,PDV对弹塑性金属材料的激光冲击强化自由表面速度能够进行准确测量,获得了符合理论分析的测量结果,特别是捕捉到了弹性前驱波;连续小波变换处理效果显著优于短时傅里叶变换.
Optical fiber laser interferometry (PDV) is a new type of velocimetry developed in recent years. It has gradually replaced arbitrary reflective surface velocimetry (VISAR) in some fields. However, at low velocities and short transient fast particle velocity measuring methods and data processing Technology is immature.In this paper, PDV measurement is carried out for non-stationary signals with typical short-time, sharp fluctuations in speed and large variations in velocity of the free surface of the target during laser shock enhancement. The short-time Fourier transform and The results show that PDV can accurately measure the free surface velocity of laser-impact-enhanced elastic-plastic materials and obtain the measurement results in line with theoretical analysis, especially the elastic precursor wave. The effect of continuous wavelet transform Significantly better than short-time Fourier transform.