Study Of Noise Control For Tractor CAB

Nowadays, the prediction and the design of the noise of the car were put in a very important position in major car companies, in order to improve the market competitiveness of their products to gain more economic benefits. In this thesis, Series of studies about forecasts and analysis of low-frequency noise of the tractor cab have been done on the basis of theoretical analysis of the sound and vibration.Firstly, This article build the model of a tractor cab called FT80 by using FEM software ANSYS, the building model was imported into BEM software LMS Virtual.lab, and vibro-acoustic coupling was achieved with the method of FEM and BEM by using LMS Virtual.lab; At last, the sound response of tractor cab with chair is calculated by using indirect BEM with software LMS Virtual.lab, The acoustic contribution of the chair and the driver of the cab was calculated and analyzed by comparing the sound response of tractor cab with no chair, chair and driver, It is proved that there is a certain impact on the noise to the tractor cab from the chair and the driver, It should be thought in building model.Secondly, Discussed the principles of noise insulation glass and the theory of solid coupling, It build the model of a tractor cab by using FEM software ANSYS and LMS Virtual.lab, using the acoustic field BEM method to calculate sound-solid coupling. Compare the affect of single-layer glass and double glazing to the noise of the tractor cab. Emphatically compare and validate the difference of the driver's ear noise under the condition between the air double-decker sandwich of glass at different thickness of air-layer and different glass thickness. Make a summary the glass structure of the best sound insulation properties.Finally, it achieved the analysis to the outside acoustic field of a tractor cab with the noise analysis software LMS Virtual.lab. Compare the difference of the two methods in solving outside acoustic field. Make a summary of a more simple method to solve the outside acoustic field.In this thesis, a relatively systematic study of noise prediction from low-frequency tractor cab has been done. It provides a certain theoretical basis for reducing cab noise.