Wisse C J, Smeulders D M J, Chao G, van Dongen M E H
Department of Geotechnology, Delft University of Technology, P.O. Box 5028, 2600 GA, Delft, The Netherlands.
J Acoust Soc Am. 2007 Oct;122(4):2049-56. doi: 10.1121/1.2767418.
The classical theory of wave propagation in elastic cylinders is extended to poro-elastic mandrel modes. The classical theory predicts the existence of undamped L modes and damped C, I, and Z modes. These waves also appear in poro-elastic mandrels, but all of them become damped because of viscous effects. The presence of the Biot slow bulk wave in the poro-elastic material is responsible for the generation of additional mandrel modes. One of them was already discussed by Feng and Johnson, and the others can be grouped together as so-called D modes. The damping of these D modes is at least as high as the damping of the free-field slow wave.
