Noise Prediction Research Of Underwater Structure With Multi-Exciting Sources

Research of the vibration and. sound radiation of assembled structures with cylindrical shells has been increasingly become an advanced problem of noise and vibration control, just for the widely application of cylindrical shells in the common and national defence engineering. Predicting the noise and vibration of assembled structures with cylindrical shells is key points to realize low-noise design of structures and aircraft, especially for underwater vehicle.In the several methods of vibration and noise prediction for structures, statistical energy analysis has some merits compare to other methods. Now, FEM,BEM and modes analysis technique are widely used in the engineering field, but it become more and more difficult to predict the sound and vibration using these method along with the analysis frequency increasing, because the structures' modes become dense in the high frequency , and the calculation quantity become huge. The difficulties of other methods is just the foundation of SEA to predict the structure' noise and vibration in the high frequency. It is very convenient to carry out the prediction of sound and vibration of structure in the high frequency using SEA.For the importance of noise and vibration prediction, the author carried out the noise and vibration prediction research in high frequency for single and double cylindrical shell with beams using SEA. In the single cylindrical shell model, the exciting condition concludes single power and multi-power. and carried out the particular research of the prediction when the external power loaded in the different mode. Furthermore, some noise and vibration controlling measure was designed and the effect was predicted. In the double-shell model, the author carried out the prediction research using SEA theory and AutoSEA2. The results showed good coherence for two method. Through the sensitivity analysis of the basic parameters of SEA, some useful conclusions were drawn out, and they can be used for acoustic design of the underwater structures.