高度超静定斜拉桥的非线性分析研究-------外文翻译.doc

cable-stayed bridge
1．Abstract
A comparison on nonlinear analysis of a highly redundant cable-stayed bridge is performed in the study. The initial shapes including geometry and prestress distribution of the bridge are determined by using a two-loop iteration method, i.e., an equilibrium iteration loop and a shape iteration loop. For the initial shape analysis a linear and a nonlinear computation procedure are set up. In the former all nonlinearities of cable-stayed bridges are disregarded, and the shape iteration is carried out without considering equilibrium. In the latter all nonlinearities of the bridges are taken into consideration and both the equilibrium and the shape iteration are carried out. Based on the convergent initial shapes determined by the different procedures, the natural frequencies and vibration modes are then examined in details. Numerical results show that a convergent initial shape can be found rapidly by the two-loop iteration method, a reasonable initial shape can be determined by using the linear computation procedure, and a lot of computation efforts can thus be saved. There are only small differences in geometry and prestress distribution between the results determined by linear and nonlinear computation procedures. However, for the analysis of natural frequency and vibration modes, significant differences in the fundamental frequencies and vibration modes will occur, and the nonlinearities of the cable-stayed bridge response appear only in the modes determined on basis of the initial shape found by the nonlinear computation.
1.摘要
一个拉索高度超静定的斜拉桥的非线性分析比较在研究中被实行。 包括桥的几何学和预应力分配的初始形状是使用双重迭代的方法决定的,也就是,一个平衡迭代和一个形状迭代。对于开始的形状分析，一个线性和一个非线性计算程序被建立。以前斜拉桥所有非线性被忽视，而且形状迭代是不考虑平衡而实行的。后来桥的所有非线性被考虑到，而且平衡和形状的重复都实行了。基于收敛于一点的起始形状由不同的程序决定,自振频率和震动模态也被详细地研究。数字的结果表明收敛于一点的起始形状能由二个环的重复方法快速地得到,合理的起始形状能由线性的计算程序决定，而且那样许多计算工作将被节省。在由线性的和非线性计算程序决定的结果之间的几何学和预应力分配中只有很小的不同。然而，对于自振频率和震动模态的分析来说，基本的频率和震动模态将会有显著的不同，而且斜拉桥反应的非线性只出现在由非线性计算得到的初始形状的基础之上的模态中。