Wave Mode and Frequency Selection of Ultrasonic Guided Waves Pipe Inspection Technology

Ultrasonic guided waves technology is introduced as a new non-destructive pipe inspection method for its rapid,long distance inspection and applied to special pipes which are inaccessible to other conventional NDT methods.It enjoys widespread use in the field of long range pipe inspection.The inspection distance,as the traveling range of guided waves one,is dependent on propagation characteristics of ultrasonic guided waves. Influence of transducer type,number and ring spacing on characteristics of excited signals is investigated and ultrasonic guided waves mode selection is discussed.The problem of optimum frequency selection is studied by taking example of longitudinal guided waves mode L(0,2).The correspondent parameters,such as pipe diame- ter,thickness and suppression of other waves modes are taken into account.The best experimental frequency result can be used as a reference for site inspection.