Proposal of the evaluation function for selection of optimal measurement location in inverse-numerical acoustic analysis

Noise reduction of industrial products are needed for remediation of noise pollution. To reduce noise of the products, sound radiating surfaces needs to be identified and measure the vibration of the surfaces. As a method to identify the sound source, inverse-numerical acoustic analysis (INA) has been proposed. INA is a method that identifies the surface vibration of the observed object by using acoustic transfer functions and sound pressures measured at the field points. In the INA, the measured sound pressures are used as input data. Before measuring the sound pressures, arrangement of field point must be conducted, namely arranging the microphone position and its number. More field points lead to longer test and analysis time. Therefore, guideline for the arrangement of the field points is necessary to carry out INA efficiently. This study focuses on the standard deviations of distance between the element of the object and the field points, and proposes new evaluation function for optimal selection of the field points. The effectiveness of the evaluation function had been verified by using plate model. As a result, we confirmed that the optimal field point arrangement could be selected by using two guidelines, condition number and the proposed evaluation function.