An impedance modeling technique of a fluid-loaded structure

A methodology of modeling the fluid-loaded structures using the impedance technique is proposed. The structural response and the fluid loading effect are expressed in terms of structural impedance and the acoustic wave impedance. Then a formulation that assembles the acoustic impedance and the structural impedance is derived and can be used to determine the response of a fluid-loaded structure. The advantage is simply that the impedance can be obtained either experimentally or analytically and then the response of the fluid-loaded structure can be found using the proposed impedance coupling formula without deriving the equation of motion which usually encounters difficulties when the structure is in an irregular shape or the associated boundary conditions are complicated. Two numerical examples are presented. The first is to validate that the fluid loading calculated using the proposed methodology is the same as that from the traditional Fourier Transformation method. The second is to demonstrate the potential of this proposed method applied in analyzing an active material system which is commonly used in the vibro-acoustic control. [Work supported by NSC of Taiwan.]