不同螺栓连接内外双圈法兰的轴拉承载力研究

Bearing Capacity Study of Inner-Outer Double-Ring Flange with Different Connecting Bolts Under Axial Tension

随着电网建设的快速推进,输电塔结构日益大型化,对节点的安全可靠性提出了更高的要求。钢管外圈螺栓连接的常规刚性法兰连接形式难以满足高度高、荷载大的大跨越钢管塔的承载力要求,因此提出一种新型内外双圈螺栓法兰节点来克服传统刚性法兰存在的缺陷。以某大跨越塔为背景,设计配置螺栓强度等级不同的内外双圈法兰缩尺试件,并开展轴拉承载力对比试验,重点探讨外内圈螺栓荷载分担比例以及螺栓强度等级对其的影响。同时,进行内外双圈法兰轴拉承载力特性的非线性有限元模拟,考察内外双圈法兰的承载力特性。试验及有限元分析结果表明:内外圈螺栓的拉力分配合理,内外双圈法兰连接形式安全可靠;提高螺栓强度等级可有效减缓上下法兰板间张开量的发展趋势;当配置内外不同强度等级的螺栓时,外内圈螺栓轴拉力的比值随着荷载的增大而增大。

With the rapid development of power grid construction,a larger transmission tower structure becomes popular,which brings higher requirements for the safety and reliability of joints.Since traditional rigid flange with outside bolted connection could not satisfy with the requirements of bearing capacity for large-span transmission line tower with larger height and loads,a new inner-outer double-ring flange is proposed to overcome the deficiency of traditional flange.Under the background of a large-span transmission tower,inner-outer double-ring flange with different strength grade bolts is designed.The axial tension experiments are carried out,and the share proportion of outer to inner bolts and force transfer mechanism are mainly investigated.Also,the axial tension behavior of inner-outer double-ring flange is simulated using nonlinear FEM.The test and simulation results show that the design of the flange joints is safe and reliable.Improving the strength grade of bolts can effectively slow down the development trend of the opening between the upper and lower flange plates.When configuring different strength grade bolts,the share proportion of outer to inner bolts increases with the increase of load.