Ambient vibration test and numerical simulation for modes of wind turbine towers

Based on the theory of random vibration and system identification,ambient vibration tests of three wind turbine towers in wind-power station of Inner Mongolia Wulanyiligeng were carried out.The method of coupling overall modeling of blade,hub,nacelle and tower was put forward,and the numerical stimulation and tests results showed that the wind turbine towers can effectively avoid resonance,and meet the standard design requirements of Germanischer Lloyd;the vibrational forms of the wind turbine towers mainly are lateral bending vibration,forth-and-back bending vibration and torsional vibration;the translational damping ratio in the first mode is about 1.75%,and the torsional damping ratio in the first mode about 0.6%.The overall modeling showed excellent consistency with the test results,it could benefit wind-induced dynamic response analysis and vibration control analysis of wind turbine tower systems.