高层建筑气动弹性模型风洞试验研究

Experimental Study of Aeroelastic Effect on Tall Building

以高层建筑为研究背景,制作了气动弹性模型,通过风洞试验测得结构的时程响应结果,采用频谱分析求得结构的动力特性,采用自然激励技术法(NExT)和ARMA模型时序法以及改变模态阶数的方法获得结构的气动阻尼比,研究了结构气动阻尼比随风速的变化规律.在强风下,对顺风向的加速度响应时程结合滤波方法,消除横风向能量转移的影响,同时发现了涡激共振现象.考虑气动阻尼影响的情况下,刚体模型测压和测力得到的峰值加速度响应结果,与气动弹性模型风洞试验结果十分接近,验证气动弹性模型风洞试验结果的正确性.对于刚体模型,不考虑气动阻尼时,峰值加速度比气动弹性模型试验结果大很多,差值最大达到41%,但在某种工况下,气动阻尼的影响使结构的响应值增大,验证了考虑气动耦合作用在高层抗风研究中的必要性.

This paper studied the aeroelatic effect on tall buildings. An aeroelastic model was designed and manufactured for wind tunnel tests. With the time-history responses of the structure obtained from the aeroelastic model in the wind tunnel test, we could identify the structural dynamic characteristics by spectral analysis, and get the aerodynamic damping from the natural excitation technique method （NEXT）, the ARMA method, combined with a change in mode order, and then study the rules of aerodynamic damping changing with wind speeds. In a strong wind situation, filter technique was used to analyze the along-wind time-history acceleration response to eliminate the influence of the across-wind energy transfer. And vortex-excited resonance existed in the process of identifying the aerodynamic damping. The peak acceleration responses of the rigid models by pressure test and high-frequency-force-balance test, which considered the aerodynamic damping ratios, were very close to the results of the aeroelastic model test. The accuracy of the aeroelastic model test was verified. For the rigid models, irrespective of aerodynamic damping ratios, the peak acceleration responses were much larger than the results of the aeroelastic model test. The biggest difference was 41%. However, in some cases, the aerodynamic damping ratios increased the responses,and the necessity of considering the aerodynamic coupling effect on the wind-resistant design of flexible high-rise buildings has been verified.