摘要
以南京第四长江大桥扁平箱梁为研究对象,通过节段模型自由振动风洞试验详细测试了模型在不同风攻角下的颤振响应,探讨了系统非稳态及稳态临界振幅随风速的演化规律.首先,基于颤振响应振幅包络,结合Hilbert变换,识别了系统振幅依存的模态阻尼,并初步阐释了颤振形态随风攻角转变的机理.其次,提取了系统在不同风攻角下的模态参数,基于双模态耦合闭合解法,识别了断面在不同风攻角下的非线性颤振导数,研究了关键颤振导数振幅依存性随风攻角变化的规律及对断面颤振形态和特性的潜在影响.最后,通过逐项拆解模态阻尼,深入剖析了风攻角对非耦合及耦合气动阻尼的影响,并阐明了分项阻尼导致系统颤振性能差异性的动力学机理.
The flutter responses of the Nanjing No.4 bridge flat box girder under different wind attack angles were tested in detail through sectional model tests.The evolution of unsteady and steady critical amplitudes at different wind speeds was discussed.Based on the amplitude envelope of the flutter response and the Hilbert transform,the amplitude-dependent modal damping of the system was identified,and the mechanism of the flutter mode change with the wind angle of attack was initially explained.Secondly,the modal parameters of the system under different wind attack angles were extracted.With the bimodal coupled flutter analysis method,the nonlinear flutter derivatives of the section under different wind attack angles were identified,and the change law for the amplitude dependence of the key flutter derivatives on the wind attack angle and the potential influence on the section flutter morphology and characteristics,were studied.Finally,the effects of the wind attack angle on the uncoupled and coupled aerodynamic damping were analyzed through analyses of the modal damping subterms one by one,and the dynamic mechanism of the differential flutter performance caused by fractional damping was illustrated.
作者
邢文博
沈火明
伍波
廖海黎
XING Wenbo;SHEN Huoming;WU Bo;LIAO Haili(School of Mechanics and Aerospace Engineering,Southwest Jiaotong University,Chengdu 611756,P.R.China;Department of Bridge Engineering,Southwest Jiaotong University,Chengdu 610031,P.R.China)
出处
《应用数学和力学》
CSCD
北大核心
2023年第2期178-190,共13页
Applied Mathematics and Mechanics
基金
中央高校基本科研业务费(2682021ZTPY07)。
关键词
扁平型箱梁
软颤振
颤振导数
气动阻尼
flat box girder
soft flutter
flutter derivative
aerodynamic damping
