摘要
柔性超高层建筑在强风作用下会产生气动反馈效应,在结构振动分析中通常通过附加的非线性/线性气动阻尼和气动刚度来考虑其影响。因此,提出了一种用于此类非线性系统识别的谐波分段线性化-最小二乘回归方法。该方法不但可以识别灰箱系统,即已知典型非线性振动系统方程,仅需识别其系统参数,还可以识别黑箱系统,即非线性振动系统的方程和参数均未知。该方法首先把非线性振动系统视为分段的线性振动系统并识别出时变的阻尼比,然后根据最小二乘回归分析获得阻尼比与时间或振幅的关系表达式,最终建立其非线性振动方程。最后,以492m的上海环球金融中心为研究对象进行了气动弹性模型振动测量风洞试验,首先采用随机减量法对横风向振动位移响应进行处理获得其自由振动响应,然后应用谐波分段线性化-最小二乘法识别其横风向非线性/线性气动阻尼比和气动刚度,并讨论了其平均气动阻尼比(线性)、气动刚度、非线性气动参数随风速的变化情况。研究结果表明:该方法对识别柔性超高层建筑在强风作用下的此类非线性振动黑箱系统是可行的。
Flexible high-rise building would generate aerodynamic feedback effect subjected to strong wind. In the analysis of structural vibration, the additional nonlinear/linear aerodynamic damping and aerodynamic stiffness are generally taken to con-sider the effect. Therefore ？ a harmonic piecewise linearization-least square regression method is proposed for identification of this kind of nonlinear vibration system. It can not only identify the Grey Box system, i. e. having known the oscillation equa-tion of typical nonlinear vibration system and only need identifying the system parameters, but also identify the Black Box sys-tem ,i. e. having not known both the oscillation equation and the parameters of nonlinear vibration system. Based on the pro-posed method, the nonlinear vibration system is firstly regarded as a piecewise linear vibration system and the time-varying damping ratio is then identified by the segment method, secondly, the relation expression of damping to time or amplitude can be obtained by the least square regression method, and finally, the nonlinear oscillation equation is established. At last, the proposed harmonic piecewise linearization-least square regression method is used to identify the wind-induced across-wind non-linear/linear aerodynamic damping ratio and aerodynamic stiffness of shanghai World Financial Center based on the aeroelastic model vibration measurement wind tunnel test. The effects of wind speed on mean aerodynamic damping ratio （linear） , aero-dynamic stiffness, and nonlinear aerodynamic parameters are discussed. The results show that the proposed method is feasible for identification of this kind of nonlinear vibration Black Box system such as flexible high-rise building subjected to strong wind.
出处
《振动工程学报》
EI
CSCD
北大核心
2017年第6期983-992,共10页
Journal of Vibration Engineering
基金
国家自然科学青年基金资助项目(51208524)
湖南省自然科学基金资助项目(12JJ4055
2017JJ2318)
湖南省高校创新平台开放基金资助项目(14K104)
关键词
超高层建筑
风洞实验
参数识别
风致振动
分段线性化-最小二乘法
high-rise building
wind tunnel test
parameter identification
wind-induced vibration
piecewise linearization-least square method
