Theoretical and experimental research on controlling guided waves propagation direction in pipes

The theoretical formula of guided waves propagation direction in pipes is derived. The single direction propagation of ultrasonic guided waves in pipes are numerical simulated and experimented by setting up the gap length between magnetostrictive sensors with λ/4 and 3λ/4, and the phase difference of two excitation channels with π/2, -π/2, respectively. The research results show that, when two excitation channels condition are thoroughly the same, and the gap length between two excitation sensors is an odd multiple of λ/4 and the phase difference between two excitation channels is an odd multiple of π/2, guided waves single direction propagation will be achieved. This conclusion is consistent with the results of the theoretical formula derived, numerical simulation and experiment by done.