材料变异时大跨悬索桥的静力分析

作为大型柔性结构，悬索桥具有显著的几何非线性行为，而且存在材料特性的变异。在结构分析中，确定性有限元法不能预测材料随机因素的影响。文中建立了以增量形式表达的非线性摄动法随机有限元列式，并编制了悬索桥静力分析程序ＳＮＡＰ。经典算例表明，ＳＮＡＰ程序能有效地求解确定性非线性问题及建立离散随机场。最后针对一座在建悬索桥，计算了该桥在竖向活载作用下考虑缆索材料随机性时主梁跨中点位移的变化。结果表明，材料随机性的影响十分明显

Static analysis for long span suspension bridges with random property

Based on perturbation method, an analytical method of the static problems of long span suspension bridges is presented in this paper. An incremental formulation is established for the nonlinear stochastic finite element method SFEM of static problems, which can involve in the geometric nonlinearity such as large displacement and beam column effect. Classic numerical examples demonstrate that the program developed according to the proposed method is reliable for the analysis of deterministic geometric nonlinearity behavior and the establishment of discrete random fields. Finally, the midspan deflection of a long span suspension bridge under vertical live load is analyzed when the elastic module of cable and hangers are assumed to be random correlated variables. Numerical results show that the material randomness has a significant effect on the midspan deflection.