咬边缺陷对网架焊接空心球节点钢管焊趾处应力集中的影响分析

Analysis of the Influence of Undercut Defect on the Stress Concentration at the Weld of the Steel Tube of the Welded Hollow Ball Joint

摘要: 针对钢结构设计施工中存在的焊接空心球节点焊接缺陷问题，本文拟采用有限元分析软件ABAQUS，模拟分析研究无缺陷时空心球直径壁厚和钢管直径壁厚对焊接空心球节点钢管焊趾处应力集中的影响，以及钢管焊趾存在咬边时对焊接空心球节点应力集中的影响。结果表明，随着钢管咬边深度及锐度的增大，钢管焊趾处应力集中系数显著增大，导致钢管焊趾处的疲劳破坏，所以钢管焊趾处咬边应引起足够重视。拟合出关于钢管焊趾处咬边的应力集中系数的通用公式。

Abstract: In view of the welding defects of welded hollow ball joints in steel structure design and construction, this paper intends to use finite element analysis soft ABAQUS to simulate and analyze the effect of the wall thickness of hollow spheres and the diameter of steel pipe diameter without defects on welded hollow ball joints, and the effect of stress concentration at the toe and the influence of the undercut on the stress concentration of the welded hollow ball joints. The results show that with the increase of the undercut and sharpness of the steel pipe, the stress concentration factor at the weld toe of the steel pipe increases remarkably, which leads to the fatigue damage at the weld toe of the steel pipe. Therefore, the undercut at the weld toe of the steel pipe should be paid enough attention. A general formula for the stress concentration factor of the undercut at the weld toe of the steel tube is fitted.