PSI - Issue 22

S.M. Xie et al. / Procedia Structural Integrity 22 (2019) 353–360

360

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Author name / Structural Integrity Procedia 00 (2019) 000 – 000

Using the DVS1608-2011 standard, the accuracy grade of weld 2 was reduced from CPA to CPC2, and the allowable fatigue strength in three directions was reduced. At this time, the stress factor was increased from 0.126 to 0.218, and the stress state level was unchanged; The accuracy grade of weld 6 was reduced from CPB to CPC2, and the allowable fatigue strength in three directions was reduced. At this time, its stress factor increases from 0.456 to 0.513, and the stress state level remains unchanged; The accuracy grade of weld 7 was reduced from CPCB to CPC2, and the allowable fatigue strength in three directions was reduced ； At this time, its stress factors increase from 0.219 to 0.761, and the stress state level was raised from low to medium. The results of the analysis are shown in Table3. The comparative analysis of Table2 and Table3 shows that: the stress level assessed by IIW-2008 standard is high, for example: the stress factor of weld 6 assessed by IIW-2008 standard is 0.811, and the stress level is medium; The stress factor assessed by DVS1608-2011 standard is 0.456, and the stress level is low. The reason is that the allowable fatigue strength of the three directions determined by DVS1608-2011 standard is 28.235MPa, 37.755MPa and 18.291MPa respectively, which are higher than the allowable fatigue strength of the weld 6 determined by the IIW-2008 standard of 16.4MPa. 5. Conclusion 1) Aiming at the existence of a large number of complex welds in aluminium alloy body of EMU, by combining the programming of evaluation method with the visualization of HyperView, the workload of evaluation can be greatly reduced, the calculation efficiency can be improved, and a large amount of time and computer resources can be saved ； 2) Under accelerated fatigue condition, the weak parts of fatigue occur in the weld area between the doorpost of side wall and side wall, the longitudinal weld area between side beam and side wall, and the weld area near the roof air-conditioning frame. The stress level assessed by IIW-2008 standard is higher than that assessed by DVS1608 standard. The allowable fatigue strength amplitude of DVS1608 standard determined by accuracy grade is obviously higher than that of IIW-2008 standard determined by FAT level. Therefore, it is more stringent to evaluate the stress status of vehicle body welded joints based on IIW-2008 standard; 3) The method of evaluating stress state level of welded joints of aluminium alloy EMU body by using DVS1608 and IIW-2008 standards can be extended to the evaluation of stress state level of welded joints of other rail vehicles. References [1] Liu Kun. The Research of Ability of Anti-fatigue for Aluminum Alloy Vehicle Body[D]. Dalian Jiaotong University, 2013. [2] Song Ye. Evaluation Theory and Experimental Study of Emu Vehicle body Fatigue Life[D]. Southwest Jiaotong University, 2016. [3] Xie Su-ming, Han Bing, Zhao Wen-zhong. Study on Welded Joint Stress Concentration of Aluminum Alloy Vehicle Body[J]. Journal of Dalian Jiaotong University, 2018, 39(01):16. [4] BS EN 15085. Railway applications – Welding of rail vehicles and components. 2007 [5] DVS1608. Gestaltung und Festigkeitsbewertung von Schweißkonstruktionen aus Aluminiumlegierungen im Schienenfahrzeugbau. 2011 [6] IIW-1823-2008 Joint Working Group.XIII-1965-03/XV-1127-03 IIW-1823-2008 document Recommendations for fatigue design of welded joints and components[S].England:IIW-1823-2008 / IIS,2003. [7] China Railway Inspection and Certification (Qingdao) Vehicle Inspection Station Co., Ltd.Quality Inspection Report of Vehicle Body of China Standard EMU with Speed of 250 km/h. [8] EN 12663-1. Railway applications-Structural requirements of railway vehicle bodies. 2015.