To verify the applicability of laser Doppler vibrometer(LDV)for quick modal parameters identification for high-rise buildings,an ambient vibration test method using two LDVs remotely positioned was proposed.The vibration test of a cantilever lamp pole was performed to measure the velocity response.This method is convenient to conduct,and the accuracy of measurement can meet the requirement of applications.The modal parameters of this structure were identified based on frequency domain decomposition(FDD)and stochastic subspace identification(SSI)in this paper,providing an experimental basis for further application to large-scale structures like high-rise buildings under environmental excitation.The results show that both methods can effectively extract natural frequencies and mode shapes of the structure,of which the difference between the identified natural frequencies of the two methods is very little,while the identified mode shapes are nearly the same.Besides,finite element analysis of the lamp pole with a simplified model was carried out.By comparing with numerical modal results,the identified mode shapes agreed well,but the natural frequencies presented some difference between the modal identification results and the numerical results.To avoid mode absence and false modes,multi modal identification methods should be combined for modal analysis.At last,this method was used for vibration measurement of a super high-rise building under environmental excitation,and its modal parameter was identified.
关键词
激光多普勒/远距离测振/工作模态分析/随机子空间法/振型
Key words
laser-Doppler/remote sensing of vibration/operational modal analysis/stochastic subspace identification/mode shape
维普
万方数据