输电铁塔螺栓节点连接滑移特性及模型参数研究

The tensile tests of 21 groups of transmission tower bolted connection specimens were completed. The finite element simulation analysis of typical specimens was carried out using ABAQUS software, and the influence laws of parameters such as initial clearance, bolt torque, roughness of contact surface, diameter of bolt holes and strength of connecting members on the load-deformation curves of bolted joints were studied. According to the exponential model and the improved piecewise polynomial model respectively, the nonlinear fitting of the load-deformation test curves with 1, 2 and 3 bolts at the fixed end was carried out, the fitting parameter values of the two models were determined, the feasibility of the application of the two models in the structural analysis of transmission towers was analyzed, and the exponential model with clear physical meaning and wider application range was recommended. For the three cases of maximum clearance, ideal clearance and minimum clearance, the load-deformation fitting curves obtained by the exponential model are in good agreement with the test curves and can accurately describe the slip process of bolted connections; the error of the fitting curve and the test curve in the linear increasing section of the minimum clearance condition is relatively large, and the maximum relative difference range is about 10% - 20%.

完成了21组输电铁塔螺栓连接试件的拉伸试验，采用ABAQUS软件对典型试件进行了有限元仿真分析，研究了初始间隙、螺栓扭矩、接触面粗糙程度、螺栓孔直径和连接杆件强度等参数对螺栓节点荷载-变形曲线的影响规律。分别按照指数模型和改进的分段多项式模型，对固定端螺栓数量为1、2和3的荷载-变形试验曲线进行了非线性拟合，确定了两种模型的拟合参数取值，分析了两种模型在输电铁塔结构分析中应用的可行性，推荐采用物理意义明确、适用范围更广的指数模型。对于最大间隙、理想间隙和最小间隙三种情况，指数模型得到的荷载-变形拟合曲线与试验曲线吻合较好，能够准确描述螺栓连接滑移过程；最小间隙工况的拟合曲线与试验曲线在线性增加段误差相对较大，最大相对差值范围约为10%~20%。