索托桥结构分析的滑移索单元法

为在索托桥的结构分析中精确模拟连续长索的滑动,本文创建了一种新的单元。被称为“滑移索单元”的新单元有三个节点,以点接触的形式模拟索从下方绕过滑轮,它可以通过自动调整两侧索段的长度而使单元处于平衡状态,从而简化了计算。新单元算法的推导基于有限元分析的基本原理和弹性悬链线的解析解,并利用了平衡状态时单元内力之间的关系。本文介绍滑移索单元的推导过程,用设计的算例验证了它的正确性,分析了连续长索的滑移对索托桥桥面竖向变形的影响。新单元可以直接用于常规的有限元分析中,研究处于工作状态或在施工中的索结构。

Sliding cable element of structural analysis on cable-held bridge

In order to simulate the sliding of continuous cable in structural analysis of the cable-held bridge,one new element was developed in this paper.This new three-node element,which is called sliding cable element,can simulate the cable sliding under a pulley by point contact,and it simplifies computations by automatically adjusting the cable segments on each side of the pulley.The derivation was based on the foundational principles of finite element analysis,and the analytical solutions of elastic catenary,the relation of the forces in the element at equilibrium state was used.This paper describes the algorithms used by this new element,and provides examples to prove their correctness,the vertical displacement behaviors of the deck in one cable-held bridge were studied when the sliding is permitted.This new element can be incorporated into conventional finite element analysis schemes,to analysis the cable structures in service or under construction.