The propagation of symmetric Lamb wave in the hollow cylinder

Abstract

The article presents studies of the propagation velocity of the symmetric Lamb wave in a pipe with a diameter of 247 mm and a wall thickness of 8.4 mm. Studies include finite element modeling of the wave propagation process and an experiment using piezoelectric transducers with dry point contact based on sounding 600 mm of pipe at a frequency of 50 kHz. Plots of displacement components at wave propagation in the axial and circumferential directions are obtained, which show the prevalence of the longitudinal component over the vertical shear component from 6 to 30 times. The difference in the wave velocity at its propagation in the axial and circumferential directions was established, which amounted to 290 m/s. The simulation results are in satisfactory agreement with the experimental data.

The propagation of antisymmetric Lamb wave in the hollow cylinder

“…Since geometric anisotropy has the same effect on the wave velocity at any frequency [50,51], changes in the velocity range are associated with the anisotropy of the material properties and, to the greatest extent, with the velocity dispersion, caused by the influence of the pipe geometry. In this case, the more pronounced the velocity dispersion, the greater the influence on the change in the wave velocity is exerted by the pipe geometry.…”

“…When testing pipe wall thickness using an antisymmetric Lamb wave mode, the analysis of the results becomes more difficult, since all guided wave types are influenced by both the anisotropy of the pipe material properties and the geometric anisotropy. Studies on the influence of geometric anisotropy on the propagation velocity of the symmetric Lamb wave mode and the horizontally polarized shear wave are presented in [49][50][51]. Geometric anisotropy can change the wave velocity depending on the pipe geometry within the range up to 300 m/s from the calculated theoretical value.…”