The Analysis Of Residual Stress And Fatigue Life For Automobile Driving Axle Case

Recently, as an important part of recycled economy, the car remanufacturing industryhas got a fast development. To remanufacture all the key parts of automotive, we needto overcome many great difficulties. In this paper, the prediction model of fatigue lifefor axle case is proposed by X-ray detection of residual stress of axle case which isloaded. The fatigue failure and improvement measures for the axle case are analyzed.The research contents of this article are mainly represented in the following aspects:X-ray residual stress measuring technology for axle case is proposed. The testing areaof residual stress is confirmed by the analysis of common failure forms and force for theaxle case; the scheme of residual stress for axle case is made according to the latestEuropean standard test method for residual stress measurement by X-ray diffraction EN15305-2008; the scheme of bench test is made to monitor the residual stress of loadedaxle case.The prediction model of fatigue life for axle case is proposed. The relationship ofloading times and information of X-ray residual stress for axle case is analyzed. Theresults show that residual stress and FWHM are related to load times and has a certainrule in the particular parts of detection area, and the load times has a more obviousinfluence on residual stress and FWHM in the detection area except weld center. Theprediction model of fatigue life for axle case is proposed according to the relationship ofload times and X-ray residual stress information. And a detection standard of X-rayresidual stress is put forward on the basis of prediction model of fatigue life.The finite element simulation of fatigue life is studied for the axle case. Staticstrength and rigidity of axle case are studied with finite-element analysis, and the resultsshow that they meet the national standards. The finite-element analysis result of fatiguelife of axle case`is similar to that of bench test.The fatigue failure and improvement measures for the axle case are analyzed. By theanalysis of fracture appearance and finite-element analysis results, the primary cause ofaxle case is determined to stress concentration of transition of axle case body. Toimprove the fatigue life of axle case, fillet radius of axle case body is optimized onaccount of primary cause of fatigue failure.