球面咬边缺陷对焊接空心球节点应力集中影响的有限元分析

Finite element analysis and experimental verification of stress concentration of welded hollow sphere by undercut defect

为了揭示"空心球强-钢管弱"类焊接空心球节点中球面咬边缺陷导致的焊缝局部应力集中规律,采用大型有限元分析软件ABAQUS对有球面咬边缺陷的焊接空心球节点进行模拟分析,拟合出不同程度的球面咬边缺陷时应力集中系数计算公式,并通过试验进行了验证。结果表明,在疲劳载荷作用下,当球面咬边达到一定深度时,原本在钢管焊趾处的应力集中现象将会转移到球表面焊趾处,导致空心球面焊趾处的疲劳破坏;拟合的应力集中系数计算公式计算结果与试验结果基本吻合,工程中可采用该公式计算应力集中系数。

To study the local stress concentration in welded joints caused by spherical undercut defects in“Hollow ball strong-steel tube weak”welded hollow ball joints,a large finite element analysis software ABAQUS was used to simulate the welded hollow ball joints with spherical undercut defects.The formula of stress concentration factor was fitted to different degree of spherical undercut defect and verified by experiments.The results showed that under fatigue loading,the stress concentration at the weld toe of the steel pipe will be transferred to the weld toe of the ball surface when the spherical undercut reaches a certain depth,which will led to the fatigue failure of the hollow spherical weld toe.The stress concentration factor calculation formula was basically consistent with the test results,which can be used to calculate the stress concentration factor in engineering projects.