螺栓球柱节点单向受压承载力研究

Study of bearing capacity of bolted ball-cylinder jointsunder uniaxial compression

螺栓球柱节点是一种适用于无檩网架的新型空间结构节点。简要介绍了5个单向受压螺栓球柱节点的试验过程和试验现象;采用有限元软件ABAQUS建立了受压试件的数值模型,将数值分析获得的破坏模式、荷载-位移曲线与试验结果相比较,验证了数值模型的有效性。定义了节点单向受压承载力的取值准则,同时建立了80个节点数值模型对螺栓球柱节点的单向受压承载力影响参数进行了分析。数值分析结果表明：圆柱筒壁直径越小、壁厚越厚、筒壁高度越高,节点的单向受压承载力越高;与节点相连弦杆的截面宽度越大、长度越小,节点承载力越高;在空心圆柱体顶部增设加劲肋可提高螺栓球柱节点的轴向刚度和承载力。基于理论分析,拟合得到了螺栓球柱节点单向受压承载力的实用计算式。拟合计算式计算结果与试验结果的相对差值百分比均在10%以内,具有良好的工程使用价值。

Bolted ball-cylinder joints are a new kind of spatial structure joints which can be applied to non-purlin gird structures. This paper first presents observations （failure mode） and results from an experimental program of uniaxial compression tests on five bolted ball-cylinder joints. Finite established by ABAQUS. The FEA and experimental results element （FE） models of the test specimens were agreed well in terms of the failure modes and load- displacement curves, which proved the reliability of the FE models. The bearing capacity of the joints under uniaxial compress in was then defined. Eighty FE models were established to analyze the parameters affecting the uniaxial compressive bearing capacity of the joint. The FE results indicate that the bearing capacity of the joint decreases with the diameter of the cylinder and the length of the chord member, but increases with the thickness of the cylinder wall, the height of the cylinder, and the width of the cross-section of the chord member. The joints with rib stiffeners possess larger stiffness and bearing capacity than ordinary ones. Based on the theoretical analysis, practical calculation formulae for the bearing capacity of bolted ball-cylinder joints under uniaxial compression were proposed. The relative errors between the fitting formulae calculations and the numerical and experimental results are less than 10%, indicating that the formulae are of good engineering value.