7N01铝合金十字接头抗疲劳设计  

Fatigue design and prediction on cruciform joint of 7N01 aluminum alloy

作　　者：王苹[1,3] 米莉艳 于谊飞 董平沙 WANG Ping;MI Liyan;YU Yifei;DONG Pingsha(State Key Laboratory of Advanced Welding and Joining,Harbin Institute of Technology,Harbin 150001,China;Technology Resaerch Center CRRC Tangshan Co.,Ltd.,Tangshan 064000,China;School of Naval Architecture and Ocean Engineering,Harbin Insitute of Technology,Weihai 264209,China)

机构地区：[1]哈尔滨工业大学先进焊接与连接国家重点实验室,哈尔滨150001 [2]中车唐山机车车辆有限公司技术研究中心,唐山064000 [3]哈尔滨工业大学(威海),威海264209

出　　处：《焊接学报》2019年第10期20-24,I0001,I0002,共7页Transactions of The China Welding Institution

基　　金：国家重点研发计划资助项目(2017YFB1201300);国家自然科学基金资助项目(51605116)

摘　　要：首次针对铝合金十字接头的疲劳失效模式开展研究.借助有限元分析与疲劳试验相结合的研究手段,首先将传统的热点应力(HSS)与研究中的等效结构应力(equilibrium equivalent traction force/EETS)的应力集中系数对比,证实了EETS分析结果的网格不敏感性.基于此,深入分析十字接头连续板厚度、接头熔深以及加载跨距对焊趾与焊根处应力的影响,并提出有效结构应力(effective traction force)计算焊根开裂角度.结果表明,焊趾处等效结构应力不受连续板厚度、加载跨距与熔深的影响,而在焊根处,各个因素影响不一.疲劳试验与解析预测结果高度一致,承载十字接头焊根开裂角度并非45°.十字接头的抗疲劳设计需综合考虑接头几何特征与焊接质量,必须满足焊趾处等效结构应力(Ss,toe)高于焊根处等效结构应力(Ss,toe).The fatigue failure mode of aluminum alloy cruciform joint was carried out for the first time.By using the finite element analysis and fatigue test,the stress concentration factor s(SCF)of weld toe based on the traditional hot spot stress(HSS)and the equilibrium equivalent structural stress(EETS)were compared,the latter was mesh-insentive and shows high consistency.Besides,the influence of the Continuous member thickness of the joint,the penetration depth of the joint and the loading span on the EETS at the weld toe and the weld root are analyzed.And the effective traction stress was used to calculate the root cracking angle.It is found that,the equivalent structural stress at the weld toe keeps the constant,while the EETS at weld root changes with different continuous plate,the loading span and the penetration depth.The fatigue test shows that the root cracking angle is not 45°,which is consistent with the analytical prediction.The fatigue design of the cruciform joint needs to consider both the joint geometry and welding quality,which should meet the equivalent structural stress at the weld toe(Ss,toe)is higher than the equivalent structural stress(Ss,toe)at the root of the weld.

关 键 词：十字接头 抗疲劳设计 结构应力法 失效模式 

分 类 号：TG406[金属学及工艺—焊接]