流线箱梁弯扭耦合气动力非线性特性与颤振行为预测
Nonlinear Aerodynamic Characteristics and Post-flutter Performance Prediction of a Streamline Box Girder
赵林 1王达 2方根深 2崔巍 2葛耀君1
作者信息
- 1. 同济大学土木工程防灾减灾全国重点实验室,上海 200092;同济大学桥梁结构抗风技术交通运输行业重点实验室,上海 200092
- 2. 同济大学土木工程防灾减灾全国重点实验室,上海 200092
- 折叠
摘要
传统大跨度桥梁空气动力学颤振分析忽略了结构和气动力非线性,多用于预测颤振临界风速而难于对颤振后行为进行合理分析.为此,通过强迫振动试验对气动力叠加性进行详细考证,阐明其适用范围.在传统复模态特征值分析中引入了随幅值变化的结构阻尼比和颤振导数,实现了颤振后状态结构振幅的预测分析,并与风洞试验结果进行了对比验证.结果表明:试验范围(竖向振幅Ah/B≤1.0,扭转振幅Aα≤12°)内,流线箱梁断面弯扭耦合气动力近似满足叠加性;节段模型风洞试验中结构阻尼和气动力的幅值依赖性是系统非线性的主要表现形式,在复模态特征值分析中引入幅变的颤振导数和结构阻尼比可以较好地预测滞回颤振振幅随风速的变化关系.
Abstract
Due to the ignoring of structural and aerodynamic nonlinearities,traditional linear flutter theory of long-span bridges can only be applied to the critical flutter state prediction,not suitable for post-flutter state analysis.Besides,the superposition principle of aerodynamic forces is usually directly assumed to be true when analyzing bending-torsional coupled flutter.Therefore,this paper firstly verified superposition principle of aerodynamic forces and its applicable interval by forced vibration wind tunnel test,and then realized nonlinear flutter analysis by introducing the amplitude dependent structural damping ratio and flutter derivatives into the complex mode eigenvalue algorithm.The predicted post-flutter amplitude was verified by comparing with wind tunnel test results.The results show that the superposition principle of bending-torsional coupled aerodynamic forces is approximately satisfied for streamline box girder in the test range(vertical amplitude Ah/B≤1.0,torsional amplitude Aα≤12°).The predicted post flutter amplitudes show good agreement with experimental results when the amplitude dependence of both structural damping ratio and flutter derivatives are concerned,which also indicating that the amplitude dependence of structural damping and aerodynamic forces is the major nonlinearity of section model wind tunnel test system.
关键词
桥梁工程/流线箱梁断面/非线性气动力/颤振后/气动力叠加性/复模态特征值法Key words
bridge engineering/streamline box girder/nonlinear aerodynamics/post flutter/su-perposition principle of aerodynamic forces/complex mode eigenvalue引用本文复制引用
基金项目
国家自然科学基金(52378527)
国家自然科学基金(52078383)
国家自然科学基金(52008314)
出版年
2024
NETL
NSTL
万方数据