表面裂纹深度检测的非接触光声检测技术研究

提出了一种基于激光超声宽带透射系数和的表征参数,实现了表面裂纹深度的定量检测。通过有限元仿真与实验测量方法,从时域和频域分析了激光产生的瑞利波与表面裂纹的相互作用机制,采用宽带透射系数和作为表征裂纹深度的物理参数,并建立了其与表面缺陷深度之间的拟合方程。结果表明,脉冲激光产生的瑞利波对金属表面裂纹深度变化十分敏感,所提出的计算方法可用于精确判断表面裂纹的深度。本文研究成果可为工件表面裂纹的非接触检测提供潜在应用。

Non contact photoacoustic detection for surface crack depth detection

In this paper,a characterization parameter based on the sum of laser ultrasonic broadband transmission coefficient was proposed to realize the quantitative detection of surface crack depth. By means of finite element simulation and experimental measurement,the interaction mechanisms between Rayleigh waves generated by laser and surface crack are analyzed in time domain and frequency domain. The sum of wideband transmission coefficient is adopted as the physical parameters of crack depth,and established the fitting equations with the surface defect depth. The results show that the Rayleigh wave generated by pulsed laser is very sensitive to the crack depth of metal surface,and the proposed method can be used to accurately determine the crack depth of metal surface. The research results of this paper can provide potential applications for non contact detection of surface cracks on workpiece.