Surface wave conversion analysis on a lengthwise soldered circular cylindrical shell

摘要

This paper deals with wave conversion phenomena through a study of the acoustic scattering froma stiffened cylindrical shell at normal incidence. The analysis presented follows the experimentalstudy which explored the acoustic wave propagation and scattering processes in the case of air-filledsubmerged 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 significantobserved phenomena were generation, reflection, and conversion of circumnavigating waves at thesolder. The present work confirms the presence of the three phenomena through a theoreticalapproach based on the elasticity theory. In particular, resonances with new feature whosefrequencies are very close to those of the So wave are highlighted here. The origin of this newresonance feature is identified and can be associated to wave type conversions between Ao and SoLamb waves, occurring when these propagating waves encounter the solder. The air-filled stainlesssteel studied tube submerged in water has an internal lengthwise solder, which is, in theoreticalcomputations, considered as an internal axial mass layer. The reduced frequency range (k_1a)of thestudy is between 25 and 90, (k_1:wave number in water;a:external radius of the shell).