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为了研究焊接残余应力对钢框架承载力的影响,本文采用有限元分析模型,通过改变翼缘厚度和翼缘宽度提取不同分析模型的残余应力值,分析其变化规律,利用残余应力的平均值来分析残余应力对应力强度因子和对梁节点下翼缘拉应力的影响,通过比较得出结论:考虑残余应力后,I型裂纹尖端应力强度因子K_I增大,而且随着翼缘厚度和宽度的增加,残余应力对K_I的影响逐渐增大,但即使考虑残余应力,K_I也远小于平面应变断裂韧度K_(IC);考虑残余应力后梁翼缘拉应力都比不考虑残余应力时大,但随着翼缘厚度的增大,梁翼缘拉应力减小的幅度逐渐增大,而翼缘宽度增大后,梁翼缘拉应力反而有所增加,由此可见提高焊缝抗拉强度,增大梁翼缘厚度比加宽梁翼缘更有效。
In order to study the influence of welding residual stress on the bearing capacity of steel frame, finite element analysis model was adopted in this paper. The residual stress of different analytical models was extracted by changing the thickness of flange and the width of flange. The variation of residual stress was analyzed. By analyzing the influence of residual stress on the stress intensity factor and the tensile stress on the flange below the beam joint, it is concluded that the stress intensity factor K_I of Type I crack tip increases with the residual stress, and with the increase of the thickness and width of the flange However, the K_I is much smaller than the plane strain fracture toughness K_ (IC) even considering the residual stress. However, considering the residual stress, the tensile stress of the flange of the back beam is larger than that without considering the residual stress With the increase of the thickness of the flange, the tensile stress of the flange decreases gradually. When the width of the flange increases, the tensile stress of the flange increases but the tensile strength of the weld increases and the flange of the beam increases The thickness is more effective than widening the beam flange.