管对接全位置焊应力应变场三维有限元数值分析

基于有限元分析软件ANSYS,对SA335 P91钢管全位置对接打底焊温度场和应力应变场进行了三维数值模拟.建立了焊接瞬态温度场和应力应变场三维移动热源模型,得到了全位置焊时左右焊道交汇处(90°)的瞬态轴向应力和环向应力分布以及应力应变随时间变化的规律:在闭合小孔区内表面的轴向和环向应力均为拉伸应力,且环向应力比轴向应力大,并有明显的边缘应力效应;该处在高温凝固阶段的瞬态应力随小孔停留时间的延长和焊接电流的增大而减小,而其应变的变化则随之增大,这是造成打底焊时在小孔闭合区容易产生凝固裂纹的主要原因.

3D finite element simulation on stress-strain distributions in all position root butt welding of pip

Based on thermal-elastic-plastic theory,a 3-D finite element model of root butt welding of SA335 P91 steel pipe was carried out with ANSYS software.Using moving heat source,the transient temperature field and welding stress-strain field in root butt welded joint of a pipe were analyzed.Moreover,the distributions of axial and hoop transient stresses to close the two-half seam joint were investigated.The calculation results show that the axial and hoop stresses at the keyhole center are tensile,specially,the edge stress effect is remarkable where the hoop stresses are stronger than the axial ones,and how the holding time of heat source in the keyhole and the welding current influences the distribution of stresses and strain during the high temperature solidification is also discussed.