超声导波虚拟相控聚焦方法研究

Ultrasonic guided wave inspection based on synthetic phase control method

虚拟相控聚焦方法是一种新型的超声导波聚焦方法。针对现有时间反转聚焦方法与相控聚焦方法所需的多通道同步激励-接收设备研发难度大且成本高的现状,采用实验室现有单通道设备,利用多次激励-接收所采集的多组数据通过信号处理方法等效出多通道同步设备精确控制激励延迟所产生的相控聚焦效果。通过该方法与时间反转聚焦方法的聚焦效果有限元仿真与实验对比表明,该方法在现有实验设备基础之上,将缺陷回波幅度放大了2倍之多,获得了和时间反转聚焦方法相差不大的聚焦效果,同时,对检测区域进行成像,实现了缺陷的二维定位。

Synthetic phase control method is a new focusing method in ultrasonic guided wave inspection. Different from the time-reversal focusing method that requires a set of expensive multi-channel equipment with synchronization module, this method only requires single-channel equipment,which is widely used in laboratories. A post-acquisition signal processing method based on synthetic method is developed to achieve the phase control focusing effect. Both finite element analysis and experiment were carried out, and the results prove the effectiveness of the synthetic phase control method. According to the results, the normalized amplitude of the defect echo is increased by 2 times using the synthetic phase control method;and the focusing effect similar to that using time-reversal focusing method is achieved. At the same time, the image of the area under inspection is obtained and the 2D localization of the defects is realized.