摘要
温度变化不仅会改变斜拉索的索力、频率以及边界条件,引起振动过程中的分叉现象,还会破坏振动控制的鲁棒性,掩盖结构损伤识别参数以及状态评估。为了研究非均匀温度场中索梁组合结构的非线性振动行为机理。将温度效应作为索和主梁振动的边界条件,引入高精度抛物线形,考虑拉索几何非线性、倾角、索的自重弦向分力影响,推导了热力学平衡状态下的索梁组合结构耦合振动微分方程,构建了考虑温度效应的塔-索-主梁连续耦合非线性振动精细化模型。编制程序研究了温度变化对拉索和主梁的固有频率影响,以及索梁温差对桥塔-拉索-主梁连续结构参数振动的影响。结果表明:温度变化对拉索和主梁固有频率影响不同,在塔-索-主梁频率比为2∶1∶1的主共振模式下,温度变化量每增加5℃,拉索固有频率下降0. 17%-0. 2%,主梁固有频率下降4%-7%;索梁温差的拉索振动具有明显"拍"特征,且索和主梁之间存在能量传递,随着正索梁温差逐渐增大,拉索最大振动幅值减小,但振动频率逐渐增大;随着负索梁温差的增大,拉索最大响应振幅增大,振动频率逐渐减小;考虑索梁温差和端部联合激励下的拉索振幅比单一端部激励振幅要小,拍频要大,在2∶1∶1主共振和2∶1∶2的参数共振模式下,拉索振动有明显的"拍"特征,而主梁振动相对平稳。
The temperature change will not only change the cable force,frequency and boundary conditions of the cable,cause the bifurcation phenomenon in the vibration process,but also destroy the robustness of vibration control,affect structural damage identification parameters and state evaluation. In order to study the nonlinear vibration mechanism of cable-deck composite structure in non-uniform temperature field,regarding the temperature effect as the boundary condition of the vibration of cable and deck,introducing a high precision parabolic curve and considering the influence of geometrical nonlinearity,inclination angle,the dead weight and the chord component of cable,the coupled vibration differential equation of cable-girder composite structure under thermodynamic equilibrium is derived,and the continuous coupling nonlinear vibration refinement model of pylon-cable-girder considering temperature effect is established. The influence of temperature variation on the natural frequencies of stay cables and girders and parametric vibration of pylon-cable-girder are researched using the developed program. The result shows that（ 1） The influences oftemperature variation on the natural frequencies of cable and girder are different. When the frequency ratio of pylon-cable-deck is 2∶ 1∶ 1 in main resonance mode,the natural frequency of cables decreases by 0. 17%-0. 2% and the natural frequency of the girder decreases by 4%-7% with the temperature increasing by 5℃.（ 2） The vibration between girder and cable has obvious ＂beat＂feature and there is energy transfer between cable and girder. With the increasing of positive temperature difference of cable and girder,the maximum vibration amplitude of the cable decreases,but the vibration frequency rise gradually.（ 3） With the increasing of negative temperature difference of cable and girder,the maximum vibration amplitude of the cable increases,but the vibration frequency declines gradually.（ 4） The cable vibration amplitude under joint excitation of temperature and support is lower than that of single support excitation,and vibration frequency is higher. When the frequency ratio is 2 ∶ 1 ∶ 1 or 2 ∶ 1 ∶ 2 in main resonance mode,the cable vibration has obvious ＂beat＂characteristics,but the girder vibration is relatively stable.
作者
汪峰
彭章
李浩然
刘章军
WANG Feng;PENG Zhang;LI Hao-ran;LIU Zhang-jun(Hubei Key Laboratory of Disaster Prevention and Reduction,China Three Gorges University,Yichang Hubei 443002,China)
出处
《公路交通科技》
CAS
CSCD
北大核心
2018年第11期51-60,共10页
Journal of Highway and Transportation Research and Development
基金
国家自然科学基金项目(51278282)
道路桥梁与结构工程湖北省重点实验室(武汉理工大学)开放课题基金项目(DQJJ201507)
关键词
桥梁工程
耦合振动
数值仿真
索梁组合结构
温度效应
bridge engineering
coupling vibration
numerical simulation
cable-girder composite structure
temperature effect
