DOI: 10.15986/j.1006-7930.2018.01.021
应用测试原位焊缝剪切和拉剪强度的实验装置,研究建筑钢结构熔透对接焊缝瑕疵特征值(ε)对焊缝剪切强度(τ)和拉剪强度(R)的影响.研究受剪力作用的焊缝发现:焊缝存在瑕疵,其剪切强度低于母材的剪切强度.当焊接瑕疵位于焊缝核心区域(c类)时,对承受拉剪复合力的焊缝研究表明:ε小于0.150,随ε增加,焊缝拉剪强度几乎不变; ε在0.150～0.201间,ε增加,焊缝拉剪强度降低幅值较大; ε在0.201～0.453间,ε增加,焊缝拉剪强度降低幅值较小.当焊接瑕疵位于距焊缝受力方向较远的接近表面区域(r类)时,对承受拉剪复合力的焊缝研究表明:ε不大于0.005时,ε增加,焊缝拉剪强度降低幅值较小; ε大于0.005,ε增加,焊缝拉剪强度下降幅值巨大.H型对接构件受力形变研究发现:对接焊缝存在的瑕疵,不影响焊缝拉剪设计强度时,焊缝拉剪破坏,构件挠度大于设计允许值.
In designing the weld shear and tensile-shear device, there are flaws in shear strength(τ)of melting butt weld, tensile-shear strength(R)and component failure state with defective equivalent rate(ε)size variation. The shear strength of the weld line decreases to the shear strength of the base metal plate under the action of shearing force and any characteristic flaw.The defect rate of less than 0.150 c equivalent, with increased rates of weld defect equivalent tensile-shear strength is almost level straight. The c class defect equivalent rate, 0.150～0.201, will increase the weld defect equivalent tensile-shear strength reduction sensitivity. As c class defect equivalent rate falls between 0.201～0.453, the rate of defective weld tensile shear strength reduction is not sensitive, but it still showed a downward trend. The defect equivalent rate of r is 0.005, which is the dividing point of the sensitive region of the tensile-shear strength of the weld. When bigger than this point, with the increase of the defect equivalent rate, the tensile-shear strength declines rapidly. The defects in the butt welds of H type components, if the minimum design value of the tensile-shear strength of welded joints is not affected, will be damaged by the tensile-shearing failure of the welded joints, and the deflection of the H component can meet the allowable values of the design.
