Reliability Evaluation Of The Frame Of Articulated Electric Bus Body

With the increasingly prominent contradiction between energy,environment and sustainable development of automobile industry in our country,pure electric bus has become the main direction of urban public transport development because of its advantages of zero emission,low noise and simple structure.In this paper,the body skeleton of a 6186 bonded electric bus is taken as the research object,and the static and dynamic characteristics and fatigue reliability evaluation of the body are carried out,which is of great significance to improve the performance of the body and ensure the safe travel of passengers.First of all,according to the CAD drawings of the body skeleton provided by the enterprise,this paper applies SolidWorks to the 3D modeling of the whole vehicle,and then imports the model into the finite element analysis software ANSYS Workbench,and carries on the preliminary model inspection,repair and grid division.Finally,the finite element analysis model of the whole vehicle is obtained.Secondly,aiming at the above finite element model,the static strength and stiffness of the four common working conditions of the whole vehicle skeleton under the constraint of air spring are analyzed by using the Statics Structure module of Workbench,and its static characteristics are briefly evaluated.Then the free mode and constrained mode of the whole vehicle are analyzed,and the natural frequency range of the whole vehicle is between 7.526 and 20.838 Hz through the first 20 order free mode.The first ten order constrained modal analysis shows that the frequency of the whole vehicle body is between 6.196 and 19.438 Hz,which avoids the common excitation frequencies caused by road surface,motor,tire and transmission shaft.Based on the constrained modal frequency and the displacement power spectral density of class B pavement as random excitation input,the random vibration analysis of the whole vehicle skeleton is carried out,and the stress and displacement of the structure on 1σare obtained.The random fatigue strength of the vehicle skeleton is calculated by the three-zone method based on Gao Si distribution,and the fatigue damage coefficient of the maximum stress point position is less than the theoretical value 1,which indicates that the whole vehicle meets the fatigue life requirements.At last,based on the results of the stress and deformation of the four working conditions,the fatigue life of the whole vehicle skeleton is analyzed and calculated by using the fatigue analysis software nCode,and the results show that the fatigue cycle times of the limit torsion working condition node 462 435 are the least,and the fatigue life is 3.905×10~7 times.And the safety life standard(10~7 times)is met.And the reliability of the whole vehicle body structure is checked.