Numerical analysis of leaky Lamb wave propagation using a semi-analytical finite element method

Dispersion curves and wave structures for leaky Lamb waves were numerically analyzed with a semi-analytical finite element method. Solving governing equations derived for a leaky plate mode and a total transmission mode provided dispersion curves of fundamental Lamb modes and Scholte waves with several differences. The Scholte waves in the non-dispersive region were modes with large vibration in the vicinity of a single interface between a plate surface and fluid. Moreover, in low frequency-thickness product (fd) range in the dispersion curves, the Scholte waves became highly dispersive modes. Wave structures obtained for the Scholte wave in the SAFE calculations implied that the high dispersion in the low fd range is caused by the fact that wave energy of Scholte wave penetrates deeper in the plate in lower fd range and that the the opposite boundary of the plate affects the Scholte wave.