中文摘要：

为降低动车组车体加工中的焊接残余应力,开展了动车组KK端多道焊焊接残余应力仿真研究。研究中基于热弹塑性有限元理论,利用实体-壳单元混合模型以有效减小计算规模,通过壳单元实现实体与壳单元连接的方法,建立了高速动车组KK端多道焊焊接残余应力仿真有限元模型。在试验的基础上,利用双椭球模型校核焊接热源,通过提取和简化各道焊平均热循环曲线,实现热源加载,分析了KK端焊接残余应力的分布规律。在此基础上,提出采用2种分段焊的优化方案,最终的计算结果表明,分段焊可有效的减小KK端的焊接残余应力。

英文摘要：

In order to reduce the welding residual stress during the processing of car body of EMUs,a numerical simulation of welding residual stress of the KK end of EMUs has been carried out.During the study,based on the thermal elasto-plastic finite element theory and shell element method that realized the connection between solid and shell elements,a finite element model was established for the KK end of a high speed EMU to simulate the welding residual stress of multi-pass welding by combining solid-shell elements to reduce the computational scope.Based on the experiment,with the use of a double ellipsoidal model to check the welding heat source,the heat source loading was realized and distribution of the welding residual stress of the KK end was analyzed through the extraction and simplification of the mean thermal cycle curves of each weld.On this basis,two optimization schemes of subsection welding were proposed.The final calculation results showed that the subsection welding can effectively decrease the welding residual stress of the KK end.