Longitudinal guided wave propagation in a transversely isotropic rod immersed in fluid

The propagation of longitudinal guided waves in fluid-loaded transversely isotropic rods has been investigated based on the superposition of partial waves. The numerical results indicate that fluid loading causes not only significant attenuation via energy leakage into the fluid but also strongly affects the phase velocity of the modes in certain frequency ranges. There is an apparent ‘‘mode switching’’ between the two lowest-order modes when the rod is loaded by a relatively high-density fluid. This phenomenon is analogous to the anomalous topology previously observed in the Lamb wave spectra of low-density water-loaded plates.