Investigation of Sound Transmission through a Multi-layered Cylindrical Shell with Functionally Graded Po-roelastic Core and Bonded-Unbonded Configuration

In the present paper, sound transmission through a multilayered cylindrical shell with function-ally graded poroelastic (FGP) core and bonded-unbonded (B-U) configuration is analytically studied. The shell is made up of an outer functionally graded material (FGM) layer, function-ally graded poroelastic (FGP) core, air gap, and inner isotropic shell, respectively. Both the FGM and isotropic shells are governed by the first-order shear deformation theory (FSDT). Furthermore, the FGP core is assumed to be consist of a finite number of homogeneous layers, which are described by the extended full method (EFM) and related to each other by the trans-fer matrix method (TMM). Finally, the effects of some parameters on sound transmission loss (TL) of the system are analyzed such as inner and outer porosity of the FGP core, radial dis-placement of the inner shell corresponding to TL curve, and presence of the FGP core. It is shown that the presence of the FGP core improves sound transmission loss (TL) of the shell in a broadband frequency range

Keywords:

sound transmission loss , poroelastic cylindrical shell , first-order shear deformation theory , transfer matrix method.