Research On The Prediction And Control Of The Structure-borne Noise Of A Body As Vehicle Lab

With the rapid development of automobile industry and constant progress of technology in vehicles, people require higher and higher to automobile comfortableness. The internal noise level becomes the important index of weighing the grade level of the automobile. The key to reduce the internal noise level is that we should estimate the acoustic field accurately and then go on low noise optimization design to body structure during the course of designing. Work of this thesis is some research to explore in this respect.This thesis regards model of driver's cabin model of some type 50 tractor as the research object. Firstly, the finite element model of the driver's cabin model is created and then modal analysis is carried on with the ANSYS; Secondly, the modal experiment is scheduled; Thirdly, the BEM (Boundary element method) program to estimate the internal acoustic field of the vehicle is written basing on the calculation results in FEM (Finite element method); Finally, the noise reduction experiment is carried on the basis of influence degree of every element of the model. The comparison of internal acoustic field between the original structure and the improved structure can be figured out.Research contents of this thesis includes of FEM theory and calculation , ANSYS application in finite element analysis and calculation, modal analysis technology of the testing , BEM theory and calculation , MATLAB programming , influence degree theory. Some key factors such as establishment of FEM model of ANSYS , modal analysis , BEM, influence degree theory have been discussed deeply. This thesis presents the whole procedure of the prediction of internal acoustic field, so it has certain reference function to vehicle structure optimization design in low noise.