近几年兴起的激光超声检测技术, 在对微裂纹检测方面以其非接触、宽频带等优点受到广泛关注, 取得一定进展, 但是目前并没有统一的理论解释裂纹和超声信号作用机理。从能量角度分析研究发现, 裂纹的存在会消耗超声波的能量, 造成能量衰减, 同时理论计算与实际值之间存在比例系数。通过能量衰减计算公式, 设计并进行实验, 利用波形幅值的平方近似代替波形能量, 通过两者对比, 对比例系数进行拟合, 然后计算出未知裂纹深度的比例系数, 并由此反推预判未知深度裂纹对应的能量衰减值, 实现对裂纹定量检测的目的。

In recent years, the development of laser ultrasonic testing technology, in the field of micro crack detection with its non-contact, broadband and other advantages of widespread concern, and made some progress, but there is no unified theory to explain the mechanism of crack and ultra sound signal. From the angle of energy analysis. From the point of view of energy analysis, it is found that the existence of cracks will consume the energy of ultrasonic wave and cause energy attenuation, at the same time, there is a proportional coefficient between theoretical calculation and actual value. Based on the energy attenuation formula, design and conduct experiments, using the square approximation of the amplitude of the waveform to replace the waveform energy, through the comparison of the two, the proportion coefficient is fitted, and then calculate the proportion coefficient of the unknown crack depth, and then the energy attenuation value of the unknown depth crack is introduced, and the purpose of quantitative detection of crack is realized.