Originally inspired by a classical modeling methodology in electrical engineering, the transfer matrix method (TMM) has proven to be an accurate and efficient way to model layered acoustic media. In the case of fluid, or effective fluid, media, the acoustic TMM elements are conventionally modeled as two-by-two matrices. In contrast, a six-by-six matrix is required to model a poro-elastic layer because of the multiple types of waves that can propagate within it. Introduced here is a modified TMM that draws on various matrix operations to couple the six-by-six poro-elastic layer matrix with the two-by-two matrices of other acoustic elements. The matrix operations mainly include two steps: singular value decomposition and QR decomposition, which allows the order of a poro-elastic layer matrix to be reduced from six-by-six to two-by-two, so that a layered system can be modeled by multiplying together a sequence of two-by-two matrices for all the layered acoustic elements, thus finally creating a “global” two-by-two matrix. In this article, the proposed method was applied to several different layered or multi-panel structures, and the predicted acoustical properties were compared to results obtained by using other existing methods to validate the modified TMM.
Acoustical Modeling, Transfer Matrix Method, Poro-Elastic Media, Layered Structure
Acoustics and Noise Control
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