特高压钢管塔带颈锻造法兰承载性能试验与参数分析

Experimental Research and Parameter Analysis on Bearing Behavior of High-neck Forged Flange for UHV Steel Tube Tower

为了检验带颈锻造法兰安全性及合理性,针对特高压交流工程钢管塔Q345带颈锻造法兰试件进行了受拉试验,研究了不同承载力级别下带颈锻造法兰的抗拉承载性能,开展了非线性有限元分析,并与试验结果进行对比;在得到可靠的有限元模型基础上,研究了各设计参数对法兰节点受拉承载性能的影响规律。研究结果表明:各组试件的变形特征相似,即法兰连接的小直径钢管出现轴向拉伸和径向收缩现象,法兰盘轻微弯曲,法兰连接的大直径钢管变形不明显。法兰盘厚度的增加提高了法兰节点的强度和刚度,减少了法兰盘变形及螺栓附加应力;法兰颈部变坡坡度控制在15°左右为宜;法兰节点的初始刚度随螺栓预紧力的增大而增大,但节点的极限承载力变化较小;法兰节点荷载的偏心距会严重降低节点的初始刚度和承载力。研究证明,不同承载力级别下带颈锻造法兰的抗拉承载性能安全、可靠;与轴心受力相比,偏心受力会在一定程度上降低试件的承载能力。

In order to test the safety and rationality of the high-neck forged flange,the tensile test of the Q345 high-neck forged flange specimen for a UHV AC engineering steel tube tower was carried out,the tensile load of the high-neck forged flange under different bearing capacity levels was studied,and the nonlinear finite element analysis was carried out.The obtained results were compared with the experimental results.Moreover,based on the reliable finite element model,the influence of each design parameter on the tensile bearing capacity of the flange joint was studied.The research results show that the deformation forms of each group of specimens are basically the same.The steel tube with small diameter connected with the flange is axially stretched and radially contracted,the flange is slightly curved,and the deformation on the side of large tube is not obvious.With the increase of flange thickness,the bearing capacity and stiffness of flange joint are improved,and the deformation of flange and the additional stress of bolt are decreased.The flange neck slope should be controlled at about 15°.The greater the bolt preload,the greater the initial axial stiffness of the flange joint,but it has a negligilbe effect on the ultimate bearing capacity of the flange joint.The eccentricity of loads on flange joints seriously will reduce the initial stiffness and bearing capacity of the joint.The research shows that the strength graded high-neck forged flange has enough tensile bearing capacity.Compared to axial tensions,eccentric tensions partly lower the bearing capacity of the specimen.