Research on the engineering calculation method of acoustic radiation of open-frame multi-cabin structure

The open-frame multi-cabin structure is a common structure for deep-sea underwater vehicles. The numerical method on the vibration and acoustic radiation characteristics of the open-frame multi-cabin structure is of great significance for the prediction and control of underwater vehicles noise radiation. In this work, an engineering calculation method based on dynamic load identification in frequency domain was proposed for the acoustic radiation of structures excited by complex vibration sources. The dynamic model of the open-frame multi-cabin structure was established by using the finite element method (FEM). The vibration source was replaced by an equivalent load model, and the equivalent load was identified through the vibration response and the dynamic model of the structure. The key to the equivalent load identification is the selection of vibration measurement point. A method for selection of vibration measurement point in load identification process is proposed by predicting vibration response of the accelerometer validation channel. The identified load was loaded on the structural finite element model as an input to calculate the structural dynamic vibration and acoustic radiation. The equivalent load model was proposed for eccentric motors, and the load identification was verified on the stiffened plate structure. Using this method, the acoustic radiation of the open-frame multi-cabin structure was calculated and compared with experimental results. The results show that the sound pressure level at the excitation frequency of the vibration source and the overall sound pressure level are in good agreement with the experimental results. This research provides a practical engineering calculation method for radiation noise prediction of underwater vehicles.