弦支穹顶结构三维等效摩擦单元研究

A three-dimensional equivalent friction element for suspend-dome structure

弦支穹顶作为一种新型复合空间结构形式,因结构效能高、施工方便而在大跨空间结构中应用广泛.但张拉环索时不可避免存在预应力摩擦损失,降低了结构的承载性能.针对索撑节点处的滑移摩擦现象,从摩擦在结构中的精确模拟方面开展了研究.基于弹塑性力学和有限元理论,提出一种适用于弦支穹顶结构的三维等效摩擦单元,建立该单元的有限元分析格式,并组装到结构的整体刚度矩阵和荷载列阵中,模拟撑杆下节点带摩擦的滑移过程.通过对比理论推导、数值计算与张拉试验结果,验证了该摩擦单元的适用性,实现弦支穹顶结构考虑摩擦损失的有限元分析.

As a new type of hybrid space structure,the suspend-dome is widely used in long-span spatial structures due to its high structural efficiency and convenient construction.However,the prestressed friction loss inevitably exists during the tensioning process of hoop cables,therefore the bearing capacity would be reduced.In view of the sliding friction phenomenon at the cable-strut joints of the suspend-dome structure,this paper studies the accurate simulation of friction in the structure.Based on elastoplastic mechanics and finite element theory,a three-dimensional equivalent friction element suitable for suspend-dome structure is proposed.The finite element analysis format of the element is established,and it is assembled into the overall stiffness matrix and load array of the structure to complete the sliding friction process at the cable-strut joints.The applicability of the friction element is verified by comparing theoretical derivation,numerical calculation and tension experiment results.The finite element analysis of suspend-dome considering friction loss is realized.