风-列车-大跨度悬索桥系统非线性耦合振动分析

考虑大跨度悬索桥结构的几何非线性因素，建立了风-列车-桥梁耦合系统动力分析模型。为了考虑结构大位移非线性因素的影响，在有限元建模时考虑悬索桥主缆自重垂度及缆索初始内力的作用，在动力平衡微分方程中增加了几何刚度矩阵，通过自编计算程序，研究了列车与风荷载同时作用下主跨1120 m的五峰山悬索桥设计方案的线性及非线性振动响应。计算结果表明，考虑结构的大位移非线性因素对桥梁位移及加速度时程曲线变化趋势的影响不大，但会使其响应极值减小，非线性因素对桥梁加速度产生的误差影响较大而对位移的误差影响较小。

NONLINEAR DYNAMIC ANALYSIS OF A WIND-TRAIN-LONG-SPAN SUSPENSION BRIDGE COUPLING SYSTEM

A dynamic coupling model of wind-train-bridge system is established, while taking into account the geometric nonlinearity of long-span suspension bridge. The initial internal forces and the gravity-induced sag deflection of the main cables are considered when establishing the finite element model. The large displacement is calculated by adding the geometric stiffness in the dynamic equilibrium differential equations. The linear and nonlinear dynamic responses of the Wufengshan suspension bridge with a 1120 m main span are calculated using the self-written computer program. The results show that the large displacement nonlinearity of the structure does not influence the intendancy of bridge displacement and acceleration histories, but reduces the maximum values of the responses. The geometric nonlinearity influence on the bridge accelerations is more obvious than that on the displacements.