Dynamic Response Analysis Of Spar Floating Wind Turbine Considering The Nonlinearity Of Mooring System

With the process of global industrialization,the demand for energy is increasing,and human beings have to research and develop new energy sources under the current circumstances for sustainable development.As one of the green renewable energy sources,the characteristics of wide distribution and large reserves of wind energy make it develop rapidly,especially the development of offshore wind power.Compared with offshore wind turbines,offshore floating wind turbines can operate normally in more stable wind field in the deep sea,and obtain and use more wind energy,making it a hotspot in wind energy research.However,the environmental load of offshore floating wind turbines is complicated,especially when considering the nonlinearity of the anchor chain,it is more difficult to perform overall modeling and complete stress analysis on floating wind turbines.Based on the nonlinear mooring force,this study establishes an offshore floating wind turbine model,and uses MBDyn multi-body dynamics software to perform dynamic analysis on it.Among them,the motion control equation of the anchor chain model ignores the bending moment and shear force of the floating wind turbine mooring system,and a joint simplified coupling calculation scheme is proposed for the analysis and calculation of the wind turbine dynamic response.The main part of the wind turbine except the anchor chain is modeled by MBDyn open source software using the principle of multi-body dynamics,and the flexible tower is simulated by using space beams.Then use Python to complete the algorithm program of the mooring force control equation to solve the mooring force.At the same time,use the linear wave theory to obtain the hydrodynamic force through Python programming,and use the FAST software to obtain the wind load acting on the wind turbine through the blade element momentum theory,and calculate it with the main part of the wind turbine.Combine with the calculation of the main part of the wind turbine to realize joint calculation,thereby improving calculation efficiency.And for the 5MW spar floating wind turbine using free decay motion and uniform current response results to verify the model.On the basis of this joint calculation,the structural response calculation of the spar floating wind turbine system under uniform current,hydrodynamic and wind loads and the damping of the anchor chain is carried out,and the relevant data of the movement time history of the wind turbine and the anchor chain tension are obtained.Analyzing the movement characteristics of floating wind turbines and the role of anchor chain damping provide a certain reference basis for the design of wind turbines and mooring systems.