基于FEA的插管结构焊接变形规律分析

为了明确插管结构的焊接变形规律，利用有限元分析软件MSC.Marc，考虑材料非线性和几何非线性，建立了热弹塑性有限元模型，应用生死单元法分别模拟了两个插管与壳板的焊接过程.结果表明，插管发生鼓胀变形，并伴有轴线的偏移；焊缝附近的壳板发生翘曲变形，壳板其余位置刚度较小处发生较大的下塌变形.在插管结构的有限元模拟之前，通过平板对接试验与相应模型的有限元模拟对比，从特征节点的热过程、特征节点的焊接残余应力和焊后角变形三个方面论证了有限元模型及相关输入参数的合理性.

Research on residual distortion of welded tubular structure based on FEA

In order to figure out the residual distortion of welded tubular structure, a thermal-elastic-plastic model using commercial FEA software MSC.Marc was established by considering material nonlinearity and geometry nonlinearity. The active and death element method was employed to simulate the welding process of shell plate and two tubes at different locations, respectively. The results show that the welded tube exists swelling distortion with its axial line offset, and buckling deformation occurs in the shell plate near weld. Before simulation, the rationality of the input parameters were discussed by comparing the experimental and simulated results of butt joint in three aspects of thermal cycles, longitudinal and transverse residual stresses of certain locations and angular distortion.