Surface wave conversion analysis on a lengthwise soldered circular cylindrical shell.

This paper deals with wave conversion phenomena through a study of the acoustic scattering from a stiffened cylindrical shell at normal incidence. The analysis presented follows the experimental study which explored the acoustic wave propagation and scattering processes in the case of air-filled submerged cylindrical shells having internal axial solder [J. Chiumia, N. Touraine, D. Decultot, G. Maze, A. Klauson, and J. Metsaveer, J. Acoust. Soc. Am. 105, 183-193 (1999)]. The significant observed phenomena were generation, reflection, and conversion of circumnavigating waves at the solder. The present work confirms the presence of the three phenomena through a theoretical approach based on the elasticity theory. In particular, resonances with new feature whose frequencies are very close to those of the S(0) wave are highlighted here. The origin of this new resonance feature is identified and can be associated to wave type conversions between A(0) and S(0) Lamb waves, occurring when these propagating waves encounter the solder. The air-filled stainless steel studied tube submerged in water has an internal lengthwise solder, which is, in theoretical computations, considered as an internal axial mass layer. The reduced frequency range (k(1)a) of the study is between 25 and 90, (k(1): wave number in water; a: external radius of the shell).