P2J-3 Axial Power Flow Distribution of Ultrasonic Guided Waves in Composite Pipes

This paper describes a preliminary investigation of the distribution of axial power flow amplitude of longitudinal guided waves in composite pipes. The dispersion characteristics were computed on the assumption that the frequencies are real and the wavenumbers are complex numbers. The optimal location, optimal mode and its frequency-thickness products (fd) of testing were chosen according to the APF. The results show that with the change of fd, there are several maximal and minimal values of APF at the inner and outer walls of the layers. Therefore, from the power flow´s point of view, guided waves should be sensitive to the defect on the pipe´s wall at the position of maximal values of APF. The results show the correlation of APF with velocity dispersion