Experimental Modal Parameters Identification of Oil-drilling Derrick under Ambient Random Excitation
Zhou Guo-qiang · Science Technology and Engineering · 2009
Aiming at the design feature and the operating mode of drilling derrick, a number of modal test parameters is discussed in detail such as type and placement of excitations, arrangement of accelerometers, frequency resolution etc. And a effective method used to experimental modal parameters identification under ambient excitation is proposed. Modal frequencies are identified based on auto-spectrum of the structural response, and mode shape is identified in accordance with the ratio of the cross-spectral peak and the auto-spectral peak approximately. The method is simple, fast, practical and applicable to large complex steel structure, which have a certain value of the works.