Nonlinear analysis of sound transmission loss through cylindrical shell considering companion modes

Abstract

This paper investigates the nonlinear vibro-acoustic performance of simply supported cylindrical shell under oblique incident plane sound wave including companion modes participation. The cylindrical shell equation of motion is obtained employing Donnell’s nonlinear shallow shell theory. The Galerkin method is applied to the equations of motion in order to obtain the system of nonlinear nonhomogeneous second order ordinary differential equations. The considered mode shapes are two asymmetric driven and companion modes and one axisymmetric mode. Multiple Scales Method is used to determine the response of resultant nonlinear differential equations. Next, the effects of incident sound characteristics on the transmission loss factor are studied. According to the results, effect of companion mode on the transmission loss (TL) through the shell can be seen only in high frequency of the incident sound wave. In addition, at high incident angle of acoustic wave, the companion mode effect on the TL of the system is very small.