二节点曲线索单元非线性分析

本文提出了二节点曲线索单元，对拉索结构进行非线性分析。这种单元不仅能模拟大跨度索元的初始形态，而且能克服目前广泛使用的二节点直线杆单元精度不高，多节点曲线索单元自由度大，内插点坐标难以确定等缺点。文中采用修正的Lagrangian坐标描述法，由卡氏第一定理推导并得出了刚度矩阵的显示表达式，编制了相应的程序，并对若干算例进行了计算与比较，分析结果表明此单元模型有较好的精度，能适用于塔桅结构、张拉结构等大跨结构形式的非线性分析。

A TWO-NODE CURVED CABLE ELEMENT FOR NONLINEAR ANALYSIS

A two-node curved cable element is presented for nonlinear analysis of cable structures, in which the cable's initial shape of long-span structure is considered. The present method overcomes the disadvantages of two other widely used elements: two-node linear bar element which has low precision and multi-node element which is difficult to computerize for many D.O.F. Based on Updated Lagangian Formulation, the shagness mallix is derived explicitly according to the FirSt Castigliano's Theory. Program has been developed and some examples are analyzed. The results show that the proposed element is reliable and applicable for the analysis of long-span structures, such as cable-stayed towers and tension structures.