Scattering of an acoustic wave by composite cylindrical shells: Influence of inner and outer layer thicknesses on the circumferential waves

作者：Agounad Said^*; Aassif El Houcein; Khandouch Younes; Decultot Dominique; Maze Gerard

来源：Composite Structures, 2018, 187: 439-453.

DOI：10.1016/j.compstruct.2017.12.015

• Acoustic scattering
• Composite structures
• Vibration modes
• Surface waves
• Time-frequency analysis

Acoustic scattering of a plane progressive wave from the composite cylindrical shell is investigated through the solution of the wave equation and boundary conditions of stresses and displacements. The investigated range of reduced frequency extends over 0.1< k(1)a(1)< 200 (k(1') is the wave number in a fluid medium surrounding the composite cylindrical shell and a(1) is the outer radius of the shell). The far field form function for two-layered stainless steel/polymer cylindrical shell is evaluated and examined. The achieved results are compared with those obtained in the case of one-layered cylindrical shells made of stainless steel or polymer. The investigation is carried out into the influence of the inner layer thickness (polymer) on the circumferential waves of the stainless steel/polymer composite cylindrical shell on the one hand and of the outer layer thickness (stainless steel) on the other hand. This influence is studied based on the evolution of the cutoff frequencies of the circumferential waves. A comparative analysis of the evolution of the cutoff frequencies of the one-layered and composite cylindrical shells is conducted. The estimation of the cutoff frequencies is done from plane of modal identification and two time-frequency planes, the spectrogram and the reassignment spectrogram. The results show that these planes are very useful to estimate the cutoff frequencies of the circumferential waves of the composite cylindrical shell. They can therefore be suggested as an alternative of the proper modes theory which is applicable in the case of homogeneous structures.

• 出版日期2018-3-1