摘要
针对桥梁结构自身特性以及外部环境的随机性(如刚度、质量、阻尼比、气动导数等因素)所造成的桥梁的颤振临界风速不确定,难以衡量桥梁颤振稳定性问题.将概率密度演化方法与桥梁颤振多模态耦合分析方法相结合,以江阴长江大桥作为实例,通过考虑桥梁结构自身的不确定性及气动导数的不确定性,给出不同模态阻尼比及频率的概率密度演化过程.研究表明:结构模态阻尼比及频率在低风速情况下的概率密度分布可近似认为服从正态或对数正态分布,高风速下的概率密度则无法用单一的概率分布来描述,概率分布会出现双峰甚至多峰的情况;与按确定性方法到的颤振临界风速相比,按概率密度演化方法得到的颤振临界风速较小.
The critical flutter wind speed of bridges is a random variable due to the characteristics of the bridge structure and the uncertainties of the external environment(such as stiffness,mass,damping ratio,and aerodynamic derivative),which makes it difficult to investigate the flutter stability of bridges.In this study,by taking the Jiangyin Yangtze River Bridge as an example,the probability density evolution method was combined with the bridge flutter multi⁃modal coupling analysis method to analyze the probability density evolution process of different modal damping ratios and frequencies considering the uncertainties of the bridge structure and the aerodynamic derivative.The research show that the probability density distribution of the damping ratio and frequency obeyed normal or lognormal distribution at low wind speed,while that at high wind speed could not be described by a single probability distribution since conditions of bimodal or even multi⁃peak would occur.Compared with the traditional deterministic method,the critical flutter wind speed obtained by the proposed probability density evolution method was smaller.
作者
姜保宋
周志勇
唐峰
JIANG Baosong;ZHOU Zhiyong;TANG Feng(State Key Laboratory of Disaster Reduction in Civil Engineering(Tongji University),Shanghai 200092,China)
出处
《哈尔滨工业大学学报》
EI
CAS
CSCD
北大核心
2020年第3期59-67,共9页
Journal of Harbin Institute of Technology
基金
国家自然科学基金(51778365)
关键词
大跨度桥梁
颤振
概率密度演化
多模态
可靠度
临界风速
概率分布
long⁃span bridge
flutter
probability density evolution
multi⁃mode
reliability
critical wind speed
probability distribution
