GUIDED WAVE NORMAL MODES IN HOLLOW CYLINDERS WITH VISCOELASTIC COATINGS

Guided wave propagation in free hollow cylinders with viscoelastic coatings is solved by a semi‐analytical finite element (SAFE) method. Guided wave dispersion curves and attenuation curves including both axisymmetric and flexural modes are obtained. The dispersion and attenuation curves agree quite well with analytical solutions. It is shown that the guided wave modes in a viscoelastic coated hollow cylinder are orthogonal to each other. This orthogonality is derived analytically and implemented into the numerical calculations to realize mode sorting. The mode sorting result also serves as verification to the orthogonality relation. Some characteristics of the dispersion curves and their corresponding practical inspection values of such a study are discussed.