Sound Transmission Through Multilayered Cylinders Using a Transfer Matrix Method

This paper concerns the use of a Transfer Matrix (TM) method for predicting the acoustic behavior of infinite cylinders consisting of a generic arrangement of homogeneous and possibly periodic layers. In such a framework, a TM representation for media characterized by cylindrical periodicity is presented. A through-radius TM is derived for a periodic layer by manipulating the dynamic stiffness matrix related to a finite element model of a unit cell. The proposed technique is equally appealing for homogeneous layers since few elements are needed in this case. The obtained TM can be used to combine the periodic medium with layers of different nature. The global TM is then used to calculate the response of the structure to excitation. Acoustic radiation or transmission due to arbitrary internal or external excitation can be assessed and both resonant and non-resonant internal fluid conditions can be treated. Predictions with the proposed approach for cylinders consisting of homogeneous layers are compared to results presented in the literature. In order to demonstrate the usefulness of the approach the sound transmission through a cylindrical structure constructed from a heterogeneous periodic unit is also presented.