Study on Propagation Characteristics of Ultrasonic Guided Waves along the Pipe

Ultrasonic guided wave is introduced as a promising pipe inspection tool for its long inspection distance and 100% pipe wall examination. The inspection range could reach 180m at single direction from one transducer when the pipe is in ideal condition. During the process of long-range pipe inspection, guided waves may go through many girth welds and elbows. When geometry characteristics of the pipe were changed, much energy of ultrasonic guided waves would be reflected and the inspection range may decrease due to energy attenuation of guided waves. Longitudinal wave was used to study propagation characteristics of ultrasonic guided waves along an experimental steel pipe. Research was carried out on energy attenuation of guided waves when it went through seven girth welds and a piece of elbow. And its ability of sensitivity and location precision of defects, such as notch, burr and branch was investigated.