Time-varying Wind Speed Identification from Structural Responses by Modified Iterative Method

The aim of this study is to try to identify the time-varying wind speed in longitudinal direction at the referenced level from structural responses. The random fluctuating wind speed process was simulated by spectral representation method and FFT method, together with the power law used to calculate wind load. Based on the vibration equation of system in state space and regularization technique, the wind speed at referenced level can be identified from structural responses. The modified iterative method is proposed to reduce the identified errors induced by the difference of the fluctuating wind speed at different level. A 50 m tall guyed mast is selected as an example, and used to check the validation and effectiveness of the proposed method. Simulated numerical results indicated that the proposed method can be used to identify wind speed values from structural displacement responses or strain responses accurately and effectively. Displacement or strain responses obtained in two orthogonal directions at a reference level only are required for an accurate identification and modified iterative method can improve the identified results obviously.