Vibration Analysis And Optimization Of Light Truck Frame

Light truck is the most important type in the transportation of agricultural and forestry products in rural areas at present.As an important supporting component of the truck,the complex and changeable external loads suffered by the truck will eventually be transmitted to the truck frame,so the static and dynamic performance of the truck frame directly affects the success or failure of the truck design.In this paper,the finite element theory and CAE software are used to analyze the static and dynamic performance and optimize the vibration reduction of the truck frame under various working conditions,which can provide some reference for the design and optimization of the truck frame.In this paper,the performance of the frame is studied from the following four aspects:1.In this paper,the frame of a 4.5t light truck in a main engine factory in Henan Province is taken as the research object,and the three-dimensional model of the frame is established by UG software.The model is imported into HYPERWORKS to simplify geometry and mesh,and a high-quality finite element model of the frame is constructed.Through static analysis of four typical working conditions of full-load truck frame:bending,torsion,braking and turning,four typical working conditions are obtained.Displacement and stress of frame under four typical working conditions.Static analysis of the frame model is carried out under the two extreme conditions of overload turning and emergency braking turning,and the calculated results are compared with the four conditions mentioned above.2.Constrained modal analysis of frame model under full load and bending condition is carried out to obtain the first ten natural frequencies and modal modes of frame model.The excitation frequency ranges of idle speed of engine,common speed and four kinds of road roughness are calculated.The results show that the main reason of frame vibration is the resonance between road roughness excitation and low-order frequency of frame.3.On the basis of frequency response analysis of modal method,a new analysis method is proposed.According to the difference of truck load,the random vibration analysis of frame assermbly is carried out with the power spectral density of displacement caused by road roughness under three working conditions as external excitation,and the power spectral density function curves of displacement and acceleration of particles in cab and carriage assembly in the whole vehicle environment are obtained and divided into two parts.The vibration response characteristics are analyzed.4.Optimizing the frame stiffness by size optimization method to avoid the resonance frequency caused by road roughness,and verifying the optimized frame:the stress intensity and shape variables of the optimized frame meet the performance requirements,the low-order frequency of the frame is significantly increased,the resonance of the optimized frame is weakened,and the comfort of the freight car is enhanced.