Research On Systematic Method Of Ship Cabin Noise Prediction Based On SEA

With the unprecedented improvement of the national strategic position of the ocean,people are demanding more and more from all aspects of the ship.As one of the main research focuses in the engineering field in recent years,the cabin noise problem of the ship has also attracted more and more attention.Statistical energy analysis(SEA)is a practical method in the calculation of cabin noise.It can predict the excitation response of complex systems under high frequency and broadband random excitation.At present,it has been applied to the prediction of cabin noise.However,there are still many problems to be solved in the aspects of model system,system input and parameter acquisition.For this reason,this paper first introduces the research status of ship cabin noise prediction,systematically expounds the development of ship cabin noise prediction methods,and analyses the basic problems and many difficulties in ship cabin noise prediction.The analysis shows that it is difficult to predict cabin noise because cabin noise involves many coupling problems such as ship equipment,hull structure,air acoustic field,outfitting materials,etc.The existing cabin noise prediction methods still have deficiencies in the loading mode of equipment excitation load,the construction of cabin noise prediction model and the acquisition of cabin noise prediction characteristic parameters.In view of the above problems,this paper takes the engineering demand of ship cabin noise prediction as the traction to study the prediction method of ship cabin noise.It focuses on the truncation method of ship cabin noise prediction equipment model,the loading mode of equipment excitation load,the construction of ship cabin prediction model,the equivalent method of outfitting material model and the acquisition of acoustic performance parameters,and the loss factor of ship structure.Basic issues such as access.On this basis,a systematic method of ship cabin noise prediction is preliminarily formed,which aims to provide a methodological basis for ship cabin noise prediction and related research.Aiming at the problems of unclear loading mode and inefficient solution of equipment excitation load in ship cabin noise prediction,a method of equipment model truncation is proposed based on power flow theory,which verifies the effectiveness of equipment model truncation method.On this basis,the method of equipment excitation load application in the absence of base is analyzed.The research shows that when base is missing,it can be used.Changing the size of the subsystem of the hull structure plate near it to make its input impedance consistent with that of the original "base-hull structure",the vibration load of the equipment can be applied directly to the subsystem of the hull structure.The analysis of the subsystem construction of the cabin noise model shows that for the cabin with great influence on the structural noise,the construction of reinforcement tendons will reduce its noise value,while for the cabin with large influence on the structural noise,the vibration load of the equipment can be applied directly For cabins with more air noise,stiffeners have little effect on the cabin noise,which can be neglected in modeling.Aiming at the problem of obtaining input parameters of forecasting model,the outfitting material model is equivalent to material acoustic performance parameters,which verifies the validity of the outfitting material model equivalent method.On this basis,an acoustic performance analysis method of outfitting material for ships is proposed,and the validity of the method is verified by comparing the calculated value with the experimental value of sound absorption and insulation performance of outfitting material.Aiming at the problem of obtaining ship structural loss factor,the theoretical calculation method of ship structural loss factor and the testing method of ship structural loss factor are proposed.Finally,on the basis of the previous research,the systematic method and overall process of ship cabin noise prediction are preliminarily formed.Combined with the actual prediction of ship cabin noise,the preliminary analysis of ship cabin noise and the improvement measures of acoustic protection are carried out.Based on the formation of systematic method,the influence of chimney noise on ship cabin noise is analyzed in order to provide reference and analysis basis for ship cabin noise prediction.