Research On Low-noise Floating Raft Of Ship Based On Acoustic Black Hole Principle

Floating raft vibration isolation system is a common method of vibration reduction and isolation in the ship field.It can effectively suppress the transmission of equipment vibration to the hull structure,and is of great significance to the ship’s vibration and noise reduction control.How to improve the vibration reduction and isolation performance of the floating raft system is the focus of floating raft research.At present,as a hot research content in recent years,acoustic black holes have good application prospects in the field of vibration and noise reduction.For this reason,based on engineering practice,this paper proposes a systematic process method for the application of acoustic black hole structures to raft structures.The acoustic black hole structure is applied to the floating raft system to provide new ideas and references for improving the vibration isolation performance of the floating raft system and reducing the level of ship vibration and noise.First of all,this paper carries out the research on the simplification method of acoustic black hole model.Aiming at the difficulty of model meshing and the large scale of calculation caused by the continuous change of the thickness of acoustic black hole structure,the surface element grid with stepwise changes in thickness properties is used to construct the acoustic black hole structure.Model,compare the frequency domain vibration characteristics and time domain vibration characteristics of the volume element model and the surface element model,verify the effectiveness of the acoustic black hole model simplification method,and discuss the key parameters involved in the acoustic black hole model simplification method for the modeling simplification method.Influence,give the recommended value range,and provide method support for the subsequent simulation calculation of this article.Secondly,conduct research on the influence of acoustic black hole structural parameters on its vibration reduction performance.Based on the simplified method of acoustic black hole modeling,the one-dimensional acoustic black hole structure is taken as the research object,and the parameters involved in the one-dimensional acoustic black hole structure are used to reduce the vibration of the structure.The influence law of characteristics is calculated and analyzed.The specific parameters are acoustic black hole tip cut-off ratio,acoustic black hole structure power exponent parameter,damping layer length and damping layer thickness.On this basis,the two-dimensional acoustic black hole structure is taken as the research object.The influence of the size,number and location of the acoustic black hole on the vibration reduction effect is explored,which provides support for the systematic method and process of the application of the acoustic black hole in the raft structure.Thirdly,carry out the research on the influence of acoustic black holes on the vibration of typical raft structures.By setting calculation conditions with a single variable,the influence of various parameters of acoustic black holes on the vibration of typical raft structures is explored,and the recommended values of each parameter are given here;here On this basis,a systematic application process method for acoustic black holes in raft structures is proposed.The process combines actual engineering problems to determine the acoustic black hole embedding position,embedding quantity,acoustic black hole size,power exponent parameter,tip cutoff ratio and other parameters in sequence.The application scheme of acoustic black hole in raft structure is formed,and a small raft is used as the research object to verify the effectiveness of the above process.Finally,this article applies the above-mentioned systematic method and process of acoustic black hole in raft structure to a floating raft system.According to the characteristics of raft structure,an application scheme of acoustic black hole in raft structure is formed,and the acoustics are calculated and analyzed.Before and after the black hole is embedded,the vibration level drop of the floating raft vibration isolation system is changed;on this basis,the restriction on the actual processing difficulty of the project is appropriately relaxed,and the optimization scheme for the application of the acoustic black hole in the raft structure is proposed,which further improves the isolation of the raft system The vibration performance effectively reduces the mechanical noise level of the ship compartment.