Dynamic Response Analysis Of Large Wind Turbine Considering Soil-Structure Interaction Under Wind-Earthquake Coupling

The rapid development of China’s wind power industry has also brought a series of problems.On the one hand,in order to make greater use of wind energy,the design of wind turbines is also becoming more and more large,which makes its own structure more flexible,its natural vibration frequency is also lower,and it is easy to cause resonance under dynamic load and even lead to tower failure,and its dynamic response under wind load is more serious.At the same time,China is also an earthquake-prone country.Many wind farms are inevitably built in these earthquake-prone areas,which in turn makes wind turbines extremely vulnerable to ground motion during normal operation.Therefore,it is particularly important to master the dynamic response of wind turbines under wind,earthquake and their coupling.On the other hand,the influence of soil-structure interaction(SSI effect for short)cannot be ignored.Considering SSI effect may make the wind turbine produce greater dynamic response under the action of dynamic load,making it inclined to unsafe state,so it is necessary to consider the influence of SSI effect when analyzing the dynamic response of wind turbine.Therefore,it is of great significance to carry out the research on the dynamic response of wind turbines considering SSI effect under wind,earthquake and their coupling effects for the safe production of wind power in China.In view of this,this paper mainly carries out research from the following three aspects:First,take a 2.5 MW large wind turbine as the prototype,establish the integrated fine finite element model of the wind turbine "blades-nacelle-tower-foundation-soil",and use the finite slip formula to define the normal and tangential contact behavior between the soil-structure contact surfaces to consider SSI.Second,generate the wind speed by the harmonic superposition method considering the spatial coherence between the blade and the tower,and combine the leaf element momentum theory and the Gaussian wind loss wake model,Calculate the wind load acting on different areas of the wind turbine.At the same time,four types of ground motions are selected from the PEER database,namely,near-field impulse ground motions,near-field non-pulse ground motions,common far-site ground motions,and typical far-site ground motions.The EERA program is used to inverse them to obtain the input ground motions at the bottom of the model.Finally,the dynamic response of wind turbines under wind load,seismic action and their coupling is analyzed with the indicators of tower top displacement,tower body acceleration,tower body stress,tower bottom shear force,bending moment,torque,etc.,and the influence of SSI effect on wind-induced response,seismic response and wind-seismic coupling response of large wind turbines is discussed.It provides guidance value for the wind-resistant and anti-seismic design of large wind turbines in the future.