两节点曲线索单元精细分析的非线性有限元法
NONLINEAR ANALYSIS OF CABLE STRUCTURES USING A TWO-NODE CURVED CABLE ELEMENT OF HIGH PRECISION
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摘要: 从UL列式的虚功增量方程出发,引入索的基本假定,推导出了两节点曲线索单元切线刚度矩阵的显式;同时根据索的特性还导出了精确计算索单元索端力的表达式,从而建立起了一套完整的对拉索进行精细分析的非线性有限元法.应用本文方法,可进行大跨度悬索桥、斜拉桥以及张拉结构等的非线性有限元分析计算.算例结果表明,本文方法是精确有效的.Abstract: Based on the virtual work increment equation of updated Lagrangian formulation and the basic assumption of cable, a finite element method with two-node curved cable element for the geometrical non-linear analysis of cable structures is developed and its stiffness matrix is presented. With reference to the geometric shape and physical equation of cable, the node forces of cable element are accurately formulated. The present method overcomes the disadvantages of two other widely used elements: two-node linear bar element which has low precision and the multi-node element which is difficult to computerize for many D.O.F. This method in the paper can be used in the analysis of long-span suspension bridge, cable-stayed bridge and tensile structure. The results of three examples show that the proposed method is very precise and valid.