DETECTION OF LONGITUDINAL DEFECT IN PIPES USING TORSIONAL MODES  

作　　者：LIU Zenghua WU Bin HE Cunfu YANG Shiming WANG Xiuyan 

机构地区：[1]College of Mechanical Engineering and Applied Electronics Technology, Beijing University of Technology, Beijing 100022, China

出　　处：《Chinese Journal of Mechanical Engineering》2006年第1期146-150,共5页中国机械工程学报（英文版）

基　　金：This project is supported by National Natural Science Foundation of China(No. 10272007, No.60404017, No.10372009)Municipal Natural Science Foundation of Beijing, Clina(No.4052008).

摘　　要：The multi-modes and disperse characteristics of torsional modes in pipes are investigated theoretically and experimentally. At all frequencies, both phase velocity and group velocity of the lowest torsional mode T（0,1） are constant and equal to shear wave velocity. T（0,1） mode at all frequencies is the fastest torsional mode. In the experiments, T（0,1） mode is excited and received in pipes using 9 thickness shear vibration mode piezoelectric ceramic elements. Furthermore, an artificial longitudinal defect of a 4 m long pipe is detected using T（0,1） mode at 50 kHz. Experimental results show that it is feasible for longitudinal defect detection in pipes using T（0,1） mode of ultrasonic guided waves.The multi-modes and disperse characteristics of torsional modes in pipes are investigated theoretically and experimentally. At all frequencies, both phase velocity and group velocity of the lowest torsional mode T（0,1） are constant and equal to shear wave velocity. T（0,1） mode at all frequencies is the fastest torsional mode. In the experiments, T（0,1） mode is excited and received in pipes using 9 thickness shear vibration mode piezoelectric ceramic elements. Furthermore, an artificial longitudinal defect of a 4 m long pipe is detected using T（0,1） mode at 50 kHz. Experimental results show that it is feasible for longitudinal defect detection in pipes using T（0,1） mode of ultrasonic guided waves.

关 键 词：Torsional mode Pipe Longitudinal defect Detection Ultrasonic guided waves 

分 类 号：TG115.285[金属学及工艺—物理冶金]