A research on underwater structure acoustic radiation estimation based on vibration data

Abstract

This study estimates the underwater structure acoustic radiation areas, mainly in the following aspects: analytical methods, boundary element and finite element, etc. This approach is a significant for mastery and understanding of the underwater structure vibration and radiation mechanism, calculations, theoretical estimates and acoustic design. From the engineering point of view, these algorithms are faced with a huge amount of numerical calculation, a long calculation time, and frequency band is limited and other issues. A method is brought forward to estimate acoustic radiation based on vibration data from underwater structures. On the assumption that there is some transfer function relationship between underwater structure radiated noise and vibration monitoring data, the relation is multi-input, single-output and convergent, and the method of exponentially-weighted is adopted. Firstly, according to the thin shell equation and wave equation, we establish a large-scale cylindrical shell vibration/radiation model; simulate resonance relation of vibration monitoring data and acoustic radiation; and verify the method of data weighting. Then, we explain that the estimation error of acoustic radiation decreases when the number of monitoring points and the sample size increase; and, that the error will remain within a range of 3dB when the increase reaches a certain level. Finally, through the verification of ship measurement vibration monitoring and acoustic radiation data, the estimated value and the true value have a good consistency. This method has a small calculating burden and a fast speed, and it is also both reasonable and feasible. It is possible to apply the method to an engineering estimation.