Canbin Noise Prediction Method And Research On The Technology Of Controlling

Cabin noise of ship will lead to fatigue damage of hull structure, not only affectingships of all kinds of instruments, equipment, normal use, endangering the health of the crew,but also affecting the hidden nature of the ship, safety, housing, and availability.Comparedto a ship completed in a series of noise reduction measures,in the ship design stage,researching the ship cabin acoustic prediction and control technology.saves considerablecosts and shorten the construction cycle, which greatly increase the project efficiency.Therefore, it is of important theoretical significance and practical value to the shipcabin noise prediction and control methods of the research.In this paper, on the background of a typical ship model, I established a hull model toexplain on the basic principles of ship-radiated noise calculation method by means of finiteelement techniques.Boundary element methods and statistical energy method were carriedout to reaserch the low frequency noise and high frequency noise radiation of soundradiation characteristics prediction,and verify the feasibility of two kinds of predictionmethods by testing.Proposed three noise control technology: acoustic technology, acoustictechnology, vibration technology, and control technology and noise reduction for eachsimulation and analysis. I carried out simulation and analysis to every noise reduction bynoise control technology. The thesis are as follows:1. Basing on finite element software, I built the finite element model of the entire shipand carried out the vibration mode characterization of the ship.2. Described the finite element method, boundary element methods and statisticalmethods of the basic principles of energy.Obtained the dynamic equations for solving thedynamics.Using mode superposition method or the direct integration method can be obtainthe ship structural vibration, displacement, velocity and acceleration,which providing atheoretical basis for vibration analysis; Theory obtained by boundary element radiatedpower structure, sound radiation and sound radiation efficiency of the solution formula forcomputing the back of the acoustic theory.3. Using the finite element method and boundary element method,I established afinite element model of the ship based on a typical ship model. On this basis, I carried outthe modal analysis and reaserched the internal noise of the ship cabin under the same noisesource distribution; Using the low-frequency noise calculation software SYSNOISE. 4. calculate the whole ship full three-dimensional model of vibro-acoustic,whichrealizated of the finite element and boundary element software connection softwareanalysis.The results of testing the shipwith numerical simulation results are compared,which further describes the low-frequency ship noise prediction method feasibly.5. Adapting high frequency noise calculation software AutoSEA2and statisticalenergy method caculation,we build the ship statistical energy model according it’sproperity.Based on it, we take the high frequency sound radiation calculatio n and analysisand research the ship cabin’s internal noise’s distribution in the same noise source of highfrequency.Through test,we get a result,and then comparing in with numerical simulationresults, statistical energy method that forecast of high frequency noise is practical andfeasible.And we also find that the value obtained by statistical energy method of forecastingcabin radiated acou stic power is different from that of boundary element method, analysisand exp lore the reason on causing the phenomenon.6. Introduces three noise’s control technology and the principle,which is explained asfollows:the absorption technology, sound insulation technology and vibration reductiontechnology. At the same time simulations each control method and Confirms Its feasibilityrespectively.(1) Absorption technology:after laying a certain thickness of the rubber damp ingsound-absorbing material in the simulation cabin room wall,we get the abso rptiontechnology has some feasibility to reduce the cabin’s nosie by contrast the data ofexpeiment and that before.(2) Sound insulation technology: Each type of board can play a certain role of soundinsulation effect by making the experimental data calculation and analysis of the single layerplate, stiffened plate and double deck stiffened plate.what‘s more.by comparing theexperimental data one by one，we attain that the double deck stiffened plate’s effect ofmodal is more stability and the sound insulation is much better than the others，which can beapplied to engineering practice for giving theory reference.(3) Vibration reduction technology: Installing a simple shock absorbers in the hullcabin five,we get the result that vibration reduction technology palying an important role inthe vibration reduction of it by simulation, statistical energy method caculation andstatistical energy software AUTOSEA2exporting the the calculated data and comparing thedata with that before.This further proves that the vibration reduction technology’s feasibilityapplication on other engineering practice.