基于动态孔径聚焦的L型构件相控阵超声检测

由于L型构件界面形状复杂,当采用基于全矩阵数据的全聚焦方法时,声波在试样中的传播路径十分复杂,增加了试样中超声传播时间的计算难度.为了解决上述问题,提出了一种根据实际被测对象并使用全矩阵数据的动态调整聚焦方案的"动态孔径聚焦方法";然后,针对L型构件的型面特征,制定了动态孔径聚焦检测方案,并提出了基于Snell定律的声波传播时间计算方法;最后,通过时域有限差分数值仿真方法模拟全矩阵数据,验证了所提出聚焦方法的正确性;定制L型金属试样进行检测实验,检测结果与实际试样参数一致.研究表明:所提出的动态孔径聚焦方法可实现对L型构件的有效检测.

Ultrasonic phased array inspection of L-shaped components based on dynamic aperture focusing

When L-shaped component is detected by ultrasonic phased array inspection technique based on total focusing method, wave propagation path in the specimen became more complex to increase the computational difficulty of propagation time due to the complicated geometries of component. To solve this problem, a dynamic aperture focusing method, adjusting focusing program according to actual samples dynamically, was proposed on the basis of the total focusing method using full matrix data. Then, the dynamic aperture focusing program was designed for the surface characteristics of L-shaped components. A calculation method of wave propagation time was posed up based on the Snell's principle. Finally, a couple of full matrix data was simulated using the finite-difference time domain method to validate the dynamic aperture focusing method. The inspection experiment was carried out to image the defect in customized L-shaped metal specimen, yielding experiment results that are in good quantitative agreement with the true values. The results show that it is feasible and effective for dynamic aperture focusing method to test the L-shaped components.