According to the Y-ring of a heavy lift launch vehicle tank,the welding residual stress (WRS) between Y-ring and cylindrical shell was calculated by thermal-elastic-plastic finite element method.Then,stress distributions of the Y-ring under internal pressure loading with and without considering WRS were calculated in order to investigate the effect of WRS on loading behavior of the Y-ring structure.The results show that the WRS caused by the girth weld between Y-ring and cylindrical shell is very high,and the maximum Mises stress reaching 358MPa is located in partially melted zone.The WRS basically has little influence on stress distribution under loading in the region away from the joint,but increases the stress in the joint significantly,and also enlarges a little the maximum stress of the Y-ring under loading.In addition,the axial stresses at the inside surface generated by both the girth weld and internal pressure are tension stress,therefore the axial tension stress is obviously enlarged by the combined action of WRS and internal pressure.%为了阐明贮箱Y形环环缝焊接残余应力对其承载行为的影响,以大型运载火箭贮箱Y形环为研究对象,采用数值模拟计算得到Y形环与箱筒段环缝焊后残余应力;然后分别在考虑和不考虑残余应力情况下,进一步计算Y形环承受内压载荷时的应力分布.结果表明:环缝焊接在接头区域产生很大的残余应力,最大等效应力位于部分熔化区,最大值达到358 MPa;焊接残余应力对远离接头的部位承载时的应力基本没有影响,主要导致接头区域的应力提高,且使Y形环承载时的等效应力最大值也略有增大;焊接残余轴向应力和内压产生的轴向应力在接头内表面都是拉应力,两者叠加导致轴向拉应力明显增大.
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