Static And Dynamic Analysis And Structure Optimization Of The Medium-sized Bus Frame

Vehicle frame is one of the most important composition parts of the bus,what's more the static and dynamic characteristics of the vehicle frame are crucial for the vehicle performance.It has guiding significance for the rational design and manufacture of the vehicle frame to apply the finite element methods(FEM)and test technique to analyze and optimize the static and dynamic characteristics and structure of the vehicle frame.In this paper,the main research contents are as follows:(1)A finite element model for vehicle frame was built with its stiffness and modal analyzed.Geometry simplification was conducted on the vehicle frame of the bus.FEM model of the vehicle frame was built in HyperMesh.The bending and torsional stiffness of the vehicle frame was analysed.The displacement nephogram and displacement curve of every test point of the vehicle frame under loading were achieved.Based on theory of modal analysis,the six-order modal vibration pattern and modal frequency were gained by analyzing modal characteristics.Then the modal vibration pattern and frequency would be the evaluation criterion of the vehicle frame performance and provided references for subsequent structure optimization of the vehicle frame.(2)The static and dynamic of the vehicle frame was tested.From the results of these tests,the deformation curves of vehicle frame and modal parameters in various loading were gotten.By contrasting experimental and simulation data,the results of performance evaluation and structure optimization were more credible.These credible results achieved by FEM analysis and modal test experimental had great importance to performance evaluation and optimization of the vehicle frame.(3)The structure of the vehicle frame was optimized using sensitivity analysis.The thickness of the blanks was considered as the analysis object.The influences of thickness on the mass and low order natural frequency were mainly considered.Firstly,the sensitivity analysis of mass and first order natural frequency of the thickness of main part were carried out.Then the part with higher sensitive of the thickness would be the optimal object.At last,the weight of the vehicle frame decrease 10.6kg and the rate of weight decrease is 4.07%,under the premise of eligible static state and dynamic characteristics.