考虑轴力作用的X型圆钢管相贯节点平面外受弯滞回模型

HYSTERETIC MODEL FOR UNSTIFFENED CHS X-JOINTS UNDER CYCLIC OUT-OF-PLANE BENDING AND AXIAL FORCE

X型圆钢管相贯连接节点是大跨单层网壳管结构中最简单、常见的连接形式之一;地震作用时,此类节点主要承受平面外往复弯矩和轴力作用。该文建立了能考虑平面外弯矩、轴力相互作用的非刚性连接四弹簧模型,利用能量原理推导建立模型的刚度矩阵。提出根据有限元分析所得单一荷载作用下节点的广义力-广义局部变形曲线确定模型待定参变量(弹簧的位置、强度、刚度等)的方法,并引入弹簧力-变形关系的恢复力准则。通过与有限元分析和试验结果的比较,从初始刚度、极限承载力、抗震耗能等方面验证了模型的适用性。

Unstiffened CHS X-joint is one of the most simple and common configuration for the connection of steel tubes used in single-layer latticed structures with large span. The CHS X-joint is mainly subjected to the cyclic out-of-plane bending and axial force due to earthquake action. A non-rigid connection of four-spring assemblage model is proposed for the joint that can simulate the effect of interaction of axial force and out-of-plane bending moment. The stiffness matrix of the model is deduced by the stationary potential energy principle. By generalized force-deformation curves of CHS X-joints subject to axially compressive or tensile force, in-plane or out-of-plane moment respectively acquired by finite element analysis, the model parameters including the locations, strength and stiffness of springs of the model can be determined. A restoring rule is incorporated into the model. The validation of the model is demonstrated by comparison with the results of test and FEA with the items including initial stiffness, ultimate bearing capacity and dissipated energy due to plastic deformation.