Experimental identification of the radiation resistance matrix

The radiation resistance matrix allows for the calculation of structurally radiated sound power using a series of measured structural responses. Currently, estimating the radiation resistance matrix requires precise modelling of the structure which, for practical structures, can lead to estimation errors. This paper presents two methods for identifying the radiation resistance matrix for a structure using measurable structural and acoustic responses and the solution of an inverse problem. Although well suited to practical, complex structures, to allow the accuracy of the proposed methods of identifying the radiation resistance matrix to be reliably validated, they are compared with the theoretical radiation resistance matrix for a flat plate in an infinite baffle. It is shown through a simulation-based study that the accuracy of the proposed identification methods depends on the number of structural and acoustic sensors and structural forces used in the identification process. The proposed identification methods are then implemented experimentally to identify the radiation resistance matrix for a flat plate. The results demonstrate that an accurate estimate of the sound power can be obtained using the experimentally identified radiation resistance matrix using the two proposed methods, and the limits on the two methods are discussed.