球罐环焊缝接头残余应力的三维非线性有限元分析

建立了球罐环焊缝焊接温度场和焊接应力应变场三维移动热源有限元分析模型,考虑了材料的热物理性能和力学性能随温度而变化,应用单元生死技术模拟焊接填充过程,模拟计算出移动热源作用下的温度场,以及以温度场为基础的环焊缝接头焊接应力应变场的分布规律:温度场结果表明,由于焊接的热输入和速度不同,以及热源加载体积不相等,每道焊接的最高温度均不相等。应力场的分析结果表明,在球罐内表面的焊缝及近缝区,呈现双向残余拉应力(经向和周向),而在外表面的对应区域,经向残余应力是压应力,周向残余应力为拉应力。

Analysis of 3-D Nonlinear Finite Element of Residual Stresses in Spherical Tank Girth Welding

A three -dimensional FEM considering mobile heat source has been founded to analyze transient temperature field and welding stress - stain field in spherical tank girth welds. In the thermal elastic - plastic analysis, the non - linear material properties were also considered. The procedure code has been compiled to deal with the moving heat source by means of APDL of ANSYS. The method of element ＂birth and death＂ has been used to simulate the weld pool＇s melting and solidifying. Finally ,the distributions of welding temperature field and welding stress - stain field were given. The analysis results of temperature field indicated that： each maximum temperature by welding wasn＇t equal with different heat inputs, speeds and load volumes of heat source. The analysis results of stress field indicated that：there were bidirectional tensile residual stress （meridional stress and circumferential stress） on the weld seam and near the weld zone of inner surface in the spherical tank, while on the corresponding region of the outer surface, the meridional residual stress was compressive stress ,but the circumferential residual stress was tensile stress.