Analysis And Optimization Of Noise Performance Of Paver

As the consciousness of environmental protection is increasing all over the world,noise control is becoming a key problem that restricts the improvement of whole level of spreading machine.In this thesis,the noise at spreading machine's driver was looked as a main goal of noise control,and some research had been done on noise reduction for wind-cooling system which was the dominant noise source of the spreading machine.Firstly,the noise of the sample spreading machine was measured.Some methods of frequency spectrum analysis?measurement in near field and running respectively were used to identify the main noise sources,and the main noise source that have a maximum contribution to driver's parotic noise was found.Then noise mechanism in wind-cooling system was analyzed,that was a foundation for the next step of noise control in wind-cooling system.With cooling performance insurance and normal other performances,ducts of inlet and outlet were designed,and measures were:changing the direction of inlet and outlet,designing noise absorbing structure in the ducts of inlet and outlet respectively.While the noise absorbing structure designing,based on the famous acoustician Ma Daoyou's theory of micro-perforated panel constructions,sound impedance formula was deducted for a common perforated panel construction with inner wall of cavity pasted with sound-absorbing material.Besides,absorption characteristic of noise absorbing structure was discussed.With the aid of software MATLAB,complicated computing process in design was simplified.Theory of common perforated panel constructions with its inner wall of cavity pasted with sound-absorbing material was used to design noise absorbing structures.Relative to micro-perforated panel constructions,that was avoided perforating large numbers of micro-holes,and the cost of products was reduced.At the same time,the demand of noise reduction can be met.In the design process,software ANSYS of finite element analysis was used to set up the model of noise absorbing structure,and indirect boundary element method was applied to simulate noise absorbing structure in an acoustic software.The Results of simulation was in good accordance with those of measurement.The simulation is very helpful to the structure improvement and design.After the improvement,noise reduction effect was proved obvious at the inlet and outlet of wind-cooling system of the spreading machine,and driver's parotic noise was decreased obviously.