Research On The Noise Prediction & Control Method Of High Speed Ship By SEA

With the development of the economics,human beings call for high quality life more and more urgently,thus the coziness of the high speed ship draws humans attention.Presently,many countries set some relevant noise level rules of the ships and offshore equipments,if the noise level can be predict during the design period, take some prevent action or change the arrangement of the cabins,the cost can be cut and more effectively.Therefore prediction and control measurement of the high speed ship are very inportant.In this thesis,prediction of cabin noise of the high speed ship has been made using the AutoSEA software based on the Statistical Energy Analysis theory.The transmission of the cabin noise is discussed within the effect of the out-shipboard fluid,and make some discussion on the overall noise control method.Main content and conclusions are as follows:Introduce the basic theory of the Statistical Energy Analysis,which contains the history,the basical meanings and the equation.At the same time the software AutoSEA is brefly introduced,also the main functions and the use way.Using the Statistical Energy Analysis theory as the base,the shop drawing of the ship as the blueprint,the software AutoSEA as the tool,the high speed ship is easily modeled and calculated.Then the prediction noise level of the cabin wihtout out shipboard fluid and noise control treatment.In the forth chapter,out shipboard fluid is add to the medic.Comparing the noise perdiction level of with and without out shipboard fluid conditions,the result is:the noise of the cabin over the water level reduces little within the influence of the fluid; the noise of the cabin under the water lever having no prompting source reduces by 2%～10%with the influence of the fluid,and the more the cabin noise reduces the larger the distance from the prompting source;the noise of the cabin having prompting source under the water level also reduces little within the influence of the fluid.In the fifth chapter,the noise control method is introduced,and two noise control methods are compaired.Firstly,affix uniform damping plate on eight cabin bulkhead, and predict the noise level.Secondly,review the energy input of eight cabin without any noise control treatments.Tick out the subsystems whose energy output summation goes up to 50%of the whole energy input,then affix thicker damping plate and predict the noise level.At last,list the noise predict level of the two kinds of noise control treatments with the noise predict level without any noise control treatments.After comparing,one conclusion can be made:affixing thicker damping plate to important subsystem could reduce noise in the intermediate and high frequency more effectively.Cause the area of important subsystem take small proporation,this way is doable.Make a compare between noise prediction level and the noise testing level. Analyse the phenomena that the noise prediction level is higher than the noise testing level in the low frequency and lower in the high ferquency.After analysing,some suggestions are given.