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螺栓球节点在空间网格结构中应用广泛,然而由于其组成构件较多,在安装过程中容易出现高强螺栓拧入长度不足的初始缺陷.为研究该缺陷对螺栓球节点受力性能的影响,采用ANSYS软件建立了带有螺纹的螺栓球节点精细化模型,通过改变螺纹的啮合数来模拟高强螺栓的拧入长度,并利用已有试验数据对模拟方法的准确性进行了验证.在此基础上,对M20、M24、M27三种常用节点在不同拧入长度下的抗弯性能进行分析,结果表明螺栓球节点随着拧入长度的变化主要存在三种工作及破坏模式,高强螺栓拧入长度不足可严重降低节点刚度及其极限承载力.最后对上述三种节点在不同拧入长度下的抗拉性能进行模拟分析,得到了不同拧入长度下螺栓球节点抗拉承载力的退化规律及可能的破坏模式,给出了抗拉承载力降低比例与螺栓拧入长度的关系曲线,研究成果可为螺栓球节点的施工控制及相似结构的安全性能评估提供技术参考.
Bolt ball joints are widely used in the space grid structure, however, due to the large number of components, the initial defect of high strength bolts screwed into the length is prone to occur during the installation process.In order to study the influence of the defects on the mechanical properties of the bolt ball joints, ANSYS software was used to establish the screw bolt ball node refinement model, by changing the number of threads to simulate the high-strength screw into the length, and the use of existing experimental data to verify the accuracy of the simulation method in this foundation On the M20, M24, M27 three kinds of commonly used nodes in different screwing length of the bending analysis results show that there are three main changes in the screw ball with the length of screw into the work and failure mode, high-strength bolts into Lack of length can seriously reduce the node stiffness and its ultimate bearing capacity.Finally, the tensile behavior of the above three kinds of joints under different screwing lengths is simulated and the degradation rules of the tensile strength of the bolt ball joints under different screwing lengths are obtained And the possible failure mode, the relation curves between the ratio of the decrease of tensile load carrying capacity and the screw-in length of the bolt are given. The research results can be given as follows: Construction control and safety evaluation of similar structures to provide technical reference.