Research On Sound Absorption Characteristic Of Acoustic Coating And Calculation Of Ship Structure Noise Reduction

It is impossible to avoid making noise and vibration for a submarine during the voyage. The submarine has a better hidden ability when it is quieter, so it is safety. Thus the hidden ability becomes one of the basic characteristics of submarine, and submarine depends very much on hidden ability in the combat. World navies are making efforts to improve the hidden ability of submarine. Thus the study on the acoustic properties of acoustic coating and the performance of noise reduction after acoustic coating has lain on the submarine has important practical significance in safety, survivability and hidden ability.In this paper, micro acoustic properties of acoustic coating were discussed as the starting point, with the study of noise reduction performance after acoustic coating lain on the submarine as the ending point. The followings were discussed in this paper:Firstly the paper introduced two-dimensional transfer matrix theory and three-dimensional finite element theory. These two theories are used to analyze single cavity structure acoustic coating for a comparison, and the merits and drawbacks of the two methods are summarized and analyzed.Secondly, three-dimensional finite element analysis is used in multi-cavity combination structure acoustic coating. The advantages of the multi-cavity combination structure acoustic coating are summed up and the difficulties in the calculation are pointed out.Based on the empirical formula, the ship vibration and noise reduction performance are discussed. This method was approved by experiment and was systematically compiled to prediction software, so the micro-characteristic of the acoustic coating was linked to the submarine structure and the noise reduction performance are obtained.Finally based on the method of noise reduction performance of acoustic coating and prediction software, different factors which affect the noise reduction performance were discussed such as single-cavity structure, multi-cavity combination cavity structure, single shell and double shell plate thickness, ratio of acoustic coating area, and the paper has also predicted the acoustic coating noise reduction performance.