管道导波检测中传感器数量和频率特性研究

为了有效地检测管道缺陷,使用PZT传感器在管道中激励并接收超声导波,采用轴对称激励接收的方法,通过多组实验研究了导波在一定频率范围内管道端部与缺陷的第1次反射回波的幅值大小与频率之间的关系,分析了传感器中探头个数对信号大小的影响,确定了激励导波的最佳频率范围.实验表明,反射回波幅值的大小与传感器的固有特性有关,有缺陷管道检测与无缺陷管道检测的最佳实验频率一致,可以考虑以无缺陷管道的最佳实验频率作为频率选择的参考.

Study on the Number and the Frequency Characteristic of Transducers in Pipe Inspection Using Guided Waves

In order to detect defects in pipes effectively, by using PZT transducers, which are attached axis-symmetrically around the pipe, to generate and receive ultrasonic guided waves, the relationship between the echo peak-to-peak amplitude of echoes of the pipe end and defect and the exciting frequency was studied. The influence of the transducer's number to the signal was researched and the best range of frequency which was used to generate ultrasonic guided waves was determined. Experiments demonstrate that, the amplitude response is effected by the intrinsic characteristic of transducers. The experimental results show that many choices of transducer number and exciting frequency can be made to produce a good result and be kept for the reference of the pipe defect inspection with guided waves.