Investigation of three-dimensional theory on sound transmission through compressed poroelastic sandwich cylindrical shell in various boundary configurations

The present work applies three-dimensional elasticity theory as well as extended full method based on Biot’s theory to inspect the effect of compressing porous material on sound transmission loss of the multilayered cylindrical shell subjected to porous core and air-gap insulation in the presence of external flow considering various boundary configurations. According to this fact, first, three-dimensional elasticity theory is employed for the double-walled laminated composite parts of the structure which leads to governing equations with no extra assumptions as well as considering extended full method for poroelastic section which models the structure in three directions with no need to identify the frequency domain (unlike the simplified method). Consequently, the obtained equations are solved applying state space method based on approximate laminate model beside transfer matrix approach. Likewise, the procedure is followed to obtain sound transmission loss in appropriate boundary condition. Second, the influence of compressing porous core on acoustic transmission of the current structure is cleared. Furthermore, this paper includes some configurations which compare the obtained results with those available in literature to indicate the accuracy, reliability and simplicity of the present method particularly in comparison with the simplified method. Finally, some configurations are appeared in numerical result section to show the effects of the various parameters on sound transmission loss.