An identification study on the added mass and aerodynamic damping based on Hilbert-Huang Transform under the action of fluctuating wind

For the long-span roof structures which have relatively low frequency and light mass, the vibration property under the action of fluctuating wind is significantly influenced by the added mass and aerodynamic damping. The changing rule of these two parameters should be extracted from exact identification method. Based on Hibert-Huang Transform theory, empirical mode decomposition method is applied on the output signal after IIR band pass filter. Then the random decrement technique is used synchronously on all the components of degrees of freedom to obtain the free decay signal of required mode, so the frequency, damping ratio and mode shape can be identified. The results of numerical example show that this method can restrain noise effectively and extract the modal parameters of different order accurately. Taking the Geiger type cable dome as example, the added mass and aerodynamic damping under the action of fluctuating wind are identified according to the principle of highly similar mode shape, and the change law of these two parameters is also obtained compared with stationary air environment.