Vibration Reliability Analysis Of EMU Battery Box

With the continuous improvement of the EMU operation speed,the vibration reliability of equipments under the EMU has attracted more and more attention of the designers.The battery box is the bearing structure of emergency back up power,so it is very important to study its vibration reliability.The battery box,as important component of equipments under the EMU,has been working with adverse environment.The battery box has been influenced by random factors such as external excitation load,vibration between battery box and car body.These random factors make the battery box structure vibration problem significant.To ensure the safety and reliability for the battery box,it is necessary to conduct vibration reliability analysis of it.Therefore,combining with vibration theory,reliability theory and optimization design theory,vibration reliability analysis and vibration reliability optimization analysis of EMU battery box structure are carried out by means of computer simulation analysis method,and those analysis results can improve vibration reliability of the battery box and make ensure the safe and reliable for EMU operation.The main research work of this paper is as follows:(1)Vibration characteristics analysis of the battery box structure.Firstly,according to the three-dimensional geometric model of the battery box structure,the FEM of the battery box is established,and static strength analysis and check of the battery box is completed.Then,under the premise that the battery box structure meets static strength requirement,the first six inherent frequencies and modal modes of the battery box are obtained by modal analysis.Based on modal analysis,harmonic response analysis of the battery box is carried out,and the displacement response of the battery box to the external excitation load is obtained.The inherent frequencies of the battery box that resonance with external excitation load are found.(2)Vibration reliability analysis of the battery box structure.Aiming at the problem of vibration damage during the use of the battery box structure,based on vibration theory and reliability theory,a method of vibration reliability analysis of the battery box under multi-failure modes is proposed.Considering the uncertainty of external excitation load,plate thickness and material property,the limit state equation of resonance failure and strength failure of the battery box are established respectively.The resonance reliability analysis and strength reliability analysis of the battery box are carried out by using Monte Carlo method.Considering two failure modes of resonance failure and strength failure,vibration reliability of the battery box is obtained.(3)Vibration reliability optimization analysis of the battery box.In order to improve vibration reliability of the battery box,optimization design variables are found by using sensitivity analysis method,and the traditional optimization design method and reliability optimization design method are used to improve structure of the battery box.Considering the effect of random factors on vibration reliability of the battery box,a vibration reliability optimization method based on response surface is proposed by combining with experimental design,reliability analysis and optimization design.Comparing with traditional optimization results,the superiority of vibration reliability optimization method based on response surface model is verified.