【作者】 于大鹏；

【导师】 赵德有；

【作者基本信息】 大连理工大学 ， 水声工程， 2007， 硕士

【摘要】 船舶结构的振动声学分析,对于优化船舶结构的声学性能,具有重要的指导意义。长期以来无论是船东还是各国船级社或IMO、ISO等国际组织,在船舶验收时对上层建筑舱室的噪声均有较高的要求,噪声问题也日益引起船舶设计工作者的关注。但是由于船舶是一个复杂的系统,其舱室噪声问题更为复杂,许多条件和情况难以确定和量化,因此船舶上层舱室噪声的预测一直是工程上的难题。所以,能够准确预测复杂系统下船舶舱室噪声有着十分重要的理论与现实意义。本文研究应用统计能量分析方法对船舶舱室噪声预报进行研究,主要研究工作如下:(1)利用统计能量分析方法对船舶结构进行三维声学建模,预报船舶舱室噪声,并与实船舱室噪声测量数据比较分析研究:如果不考虑上层建筑等结构处的湍流脉动激励,会使预报结果偏小,建议在条件允许的情况下对湍流脉动激励给予考虑;若未对船舶舾装材料进行声学建模,数值模拟结果会比实测值偏大,如果要准确预报船舶舱室噪声,应该考虑船舶舾装材料吸声特性:应用统计能量分析方法预报船舶舱室噪声,对于不满足相应规范标准的船舶舱室噪声,应对动力设备选用弹簧减振器进行减振降噪处理,经过船舶航海舱室噪声测试检验,能够取得比较理想的减振降噪效果。(2)利用统计能量分析方法对四种船舶上层建筑布置型式进行了振动噪声分析,讨论了船舶结构噪声源和空气噪声源的传播路径,指出比较合理的船舶上层建筑的布置方案,应该将船舶舱室与上层建筑舱室分开。(3)应用统计能量分析方法,对船舶结构进行三维声学建模。计算分析表明:在激励源所在舱室敷设阻尼材料,不会明显降低此舱室噪声,但对其它舱室有降噪作用,并且自由阻尼材料比约束阻尼材料效果更好:在非激励源舱室敷设阻尼材料,能起到降噪作用,并且约束阻尼材料比自由阻尼材料效果更好。而后探讨不同声学模型对船舶舱室噪声影响:空气噪声激励对激励所在舱室声腔子系统噪声响应影响显著,结构噪声激励则对远离激励的舱室声腔子系统影响比较明显;加筋板结构对船舶舱室降噪略有作用:船舶舱底是否装油和水,对船舶舱室噪声无明显影响。并对实船结构进行三维声学建模,探讨敷设阻尼材料对船舶舱室噪声的影响。更多还原

【Abstract】 Shipboard vibration and noise are the important aspect in ship design and building. This is not only due to the requirement of national and international rules, but also due to a growing interest in reducing annoyance and discomfort to the crew and passengers. However the shipboard is a complex system, especially the shipboard cabin noise, which is difficult to be solved. So it is important to predict shipboard cabin noise in complex system.In this paper, predicting shipboard cabin noise is studied by statistical energy analysis (SEA) as follows:First of all, numerical analysis of the 3-D ship acoustic model is built by using statistical energy analysis method, and the simulation result is compared with the sailing test. The results show that, if the turbulence fluctuations excitation is not considered, the prediction noise would be smaller, so the turbulence fluctuations excitation should be calculated. If acoustic model don’t contain the shipyard outfitting material, the simulation result will be higher than the real value. Making the shipyard outfitting material into the acoustic model is advised, so that the simulation result can be precise. Basing the ship cabin noise with statistical energy analysis, choosing spring reducing vibration equipment in this paper is effective action.Secondly, the arrangement of superstructure is crucial for shipboard noise control. The proper configuration of accommodation space, engine room and funnel is very important to the noise levels on board. The influence of the different arrangements of the superstructure on shipboard noise is discussed in this thesis. Four kinds of arrangement are studied in detail. The SEA method is used to build the system models for predicting noise and vibration level on shipboard for different arrangements. The structureborne noise and airborne noise are calculated and the noise paths are diagnosed based on the SEA models. The proper arrangement is recommended based on the numerical results.Finally, numerical analysis of the 3-D ship acoustic model is built by using statistical energy analysis method. The results show that, if the engine room is laid by damping material, its noise would not be reduced, but and the other cabin noise would be reduced, and the effect of free damping material is better, as compared with constraint damping material. If the cabin where is not any exciting source is laid by damping material, we can see noise reduce in the acoustic space, and the constraint damping material works better than the free damping material. The calculation also displays that the acoustic excitation quite obviously affects the sound level of the cabin in which the acoustic excitation exists, and the structure excitation obviously impacts the cabin which is far from the structure excitation. There is only a little action on noise reduction by stiffened plate, and there is no action on noise reduction by the ballast water and ballast oil.更多还原