K型管节点焊接残余应力及其对应力集中系数的影响

Welding residual stress of K-joint and its influence on stress concentration factor

关键词:  K型管节点  焊接残余应力  退火处理  应力集中系数

Key words:  K-joint  welding residual stress  annealing treatment  stress concentration factor

摘要:

采用有限元软件ANSYS,以K型管节点为研究对象,利用生死单元技术,模拟焊接过程和退火处理过程,研究管节点的焊接残余应力,得到焊接温度场和应力场的分布。分别对考虑焊接残余应力与不考虑焊接残余应力而只考虑焊缝对结构影响的管节点模型施加轴向载荷,计算这两种模型的热点应力集中系数,得到焊接残余应力对管节点应力集中系数的影响。结果表明:对焊接管节点进行退火处理可以显著降低焊接残余应力,降低发生变形和断裂失效的风险,大幅度提高管节点的安全性能;管节点结构中热点位置及热点应力集中系数与尺寸参数、载荷类型、加载方式、焊缝结构等有关。

Abstract:

Using the finite element software ANSYS, taking K-joints as the study object, numerial simulation was performed for the welding process and the annealing process using the birth-death element technology. The welding residual stress of the managed node was studied and the distributions of welding temperature field and stress field were obtained. The axial loads were applied on two different K-joint models, one with welding residual stress and the other without welding residual stress while just considering the influence of welding seam on the K-joint. The stress concentration factors of these two models were calculated and the influence of the welding residual stress on stress concentration factor was obtained. The results show that the welding residual stress is reduced significantly using annealing process, the risk of deformation and fracture failure is reduced, and the safety performance of the managed node is greatly improved. The structure stress state is very complex, and the hot spot location and the hot spot stress concentration factor are related to size parameters, load type, loading mode, the welding seam structure.