Static And Dynamic Stress Analysis And Life Prediction Of Cooling Unit Support Structure Of Traction Converter

The lightweight design of high-speed Electricity Multiple Unit can reduce the manufacturing cost and loss,which has practical significance for high-speed railway speed.Taking the cooling unit support structure of traction converter as the research object,the lightweight design of the support structure is studied.This paper analyzes the structure composition of cooling unit and the characteristics of steel and aluminum of supporting structure,puts forward lightweight design scheme for supporting column,reasonably simplifies the structure of cooling unit,and establishes finite element analysis model.The static strength of steel structure and lightweight aluminum structure model is analyzed to evaluate whether the design is reasonable;The integrity of the two structures under accidental impact is verified by the analysis of impact load cases;Through random vibration analysis,it is proved whether the steel and aluminum structures meet the life requirements of normal operation.The results show that the maximum stress under different analysis conditions is within the allowable stress range,which indicates that the structure meets the requirements of static strength,impact load and random vibration.The modal analysis of the structure is carried out to judge the influence of the car body resonance on the structure.The results show that the supporting structures will not have resonance with the car body.The transient dynamic analysis of the structure is carried out,the stress data in the analysis is extracted,the stress spectrum is divided,the cumulative damage of steel and aluminum support structure is calculated by miner fatigue cumulative damage theory,and the fatigue life is predicted.The results show that the fatigue life of aluminum column is much lower than that of steel column after the first lightweight design,which does not meet the lightweight design expectation.In order to improve the fatigue life of the aluminum column after the lightweight design,correct the thickness of the aluminum column,do further structural optimization design,carry out simulation analysis and life prediction.By comparing with the original steel structure column,it is found that the maximum stress and fatigue life of the aluminum column after the secondary optimization meet the requirements.Finally,the aluminum structure lightweight design scheme of the supporting column of the cooling unit of the traction converter is determined,which provides a reference for the lightweight design of the Electricity Multiple Unit traction system.