Study On Finite Element Analysis And Life Prediction Method Of Tractor Frame

Tractor frame is key bearing parts of cars.Since it bears a variety of force and torsion from the road and the vehicle itself in the course of travel,thus the performance of frame structure determines the success or the failure of the vehicle's design.The continuous upgrading of super computer and the gradual perfection of computer aided engineering(CAE)technology has brought very convenient and effective means for the calculation and analysis of the automotive frame performance.Engineers can easily calculate the stiffness,strength and fatigue life of the frame by using finite element software and fatigue analysis software,which significantly shortens the time of vehicle development.(1)Based on the frame of Pro/E 3D model provided by the manufacturer,this study takes the 6 x 4 tractor frame as the research object.Hypermesh,a finite element analysis software,is adopted as the research instrument in this research.By adopting model cleaning,unit type selection,meshing,boundary condition and load parameters infliction and other steps,the stiffness and strength of the four operating models of the tractor frame under full load are calculated,thus the stress and strain values of dangerous points of frame are obtained with the aim to check of the strength and stiffness of the frame.In specific,the four operating models are respectively bending,torsion,turning and braking.(2)Through the modal analysis and calculation of the tractor frame,the first eight-order natural frequency and vibration model shape of the frame in the free mode is achieved.Then it takes both the resonance effect of the road excitation and engine excitation into consideration,which can provide key modal parameters for the following dynamic analysis of the automotive frame.(3)Based on the relevant references at home and abroad,this study put forward a nominal stress approach,which both includes the nominal stress approach in time domain and in frequency domain,in order to solve the high-cycle fatigue problem of the tractor frame.The living example calculation and the analysis of vehicle road spectrum woke together,proving the accuracy and efficiency of the prediction method of fatigue life in frequency domain.Moreover,it also has a reference value for the application and improvement of the fatigue life prediction methods of tractor frame.