EXPERIMENTAL VALIDATION AND PLOTTING GUIDED WAVE DISPERSION CURVE OF PIPE STRUCTURE

The paper theoretically analyzed the propagation characteristics of three modal guided waves in a pipeline structure. According to a deduced guided wave dispersion equation, dispersion curves of guided waves were drawn out by a numerical method. Experiment verified the validity of the established dispersion curves. In two pipes with different sectional dimensions, the guided waves of a longitudinal mode whose frequency range from 70kHz to 200kHz were excited at the end of the pipe, and the results show that the propagation velocity of L(0, 2) mode in the pipe was closed to a theoretical value, these has a certain practical significance on nondestructive tests of pipelines by using ultrasonic guided waves.