基于虚拟激励法的风荷载相干函数识别

Identification of coherence function of wind load based on virtual excitation method

采用自回归(AR)模型方法对具有空间相关性的脉动风荷载时程进行模拟。将模拟得到的风荷载时程加载到结构有限元模型中,通过动力时程分析方法分析获得结构响应时程。利用虚拟激励法识别得到风荷载功率谱密度。通过风荷载功率谱密度识别得到脉动风荷载相干函数。针对识别得到的相干函数与频率的关系,提出不同的方法对相干函数进行优化,得到与模拟所用风荷载相干函数相近的结果,验证了该识别方法的可行性。

The time history of pulse wind load with spatial correlation was simu- lated by using the auto-regressive modal （ AR modal）. The obtained time history of the wind load was applied in the finite element model of the structure, and the struc- tural response time history was obtained through dynamic time history analysis meth- od. The power spectral density of the wind load was identified and acquired by using virtual excitation method, and the coherence function of the pulse wind load was iden- tified and acquired based on the power spectral density. According to the relationship between the identified coherence function and frequency, different methods were intro- duced for optimization of coherence function, results show that the obtained coherence function is close to the original one used in the AR model, and the feasibility of the i- dentification method was verified.