Research On Full-scale Fatigue Test Loading Method Of Wind Turbine Blades Under Multi-point Counterweight

In recent years,with the continuous development of wind turbine blades to large scale,their quality problems have become increasingly prominent,and the fatigue performance of wind turbine blades is critical to the reliability of the entire wind turbine.At present,the fatigue performance of wind turbine blades at home and abroad is mainly tested by single-point loading fatigue test method.Due to the limitation of excitation force,large error of moment distribution and long test period in single-point loading fatigue test,a full-scale fatigue test loading method for wind turbine blades under multi-point counterweight is presented in this dissertation,the method is simple to operate,highly reliable and convenient for practical application,so it provides theoretical basis and practical guidance for the practical engineering application of wind turbine blades fatigue test technology,and has certain academic significance.The main research work is as follows:(1)The overall scheme of the full-scale fatigue test loading system for wind turbine blades is determined.Based on the purposes and load requirements of wind turbine blades fatigue test,various loading types,control methods and loading equipment of fatigue test are analyzed and compared,in addition,a set of hydraulic excitation type fatigue loading system is designed in combination with practical engineering application background,which solves the problems of eccentricity and insufficient excitation force of traditional fatigue loading device.(2)The relevant dynamic knowledge of wind turbine blades in full-scale fatigue test is analyzed and calculated.First,based on the design of the hydraulic excitation fatigue test loading system,a system dynamics model is established,and then the excitation force required in the loading of the fatigue test is calculated;Futhermore,with the help of material mechanics theory,the dynamic characteristics between blades sections are analyzed and calculated;Finally,based on the fatigue test data of single-point loading and the theory of cumulative fatigue damage,the bending moment optimization scheme of multi-point counterweight is proposed.(3)The optimization model of multi-point counterweight fatigue test loading method is established and verified.Based on single-point excitation multi-point counterweight fatigue loading scheme,the actual tested bending moment of wind turbine blades is analyzed and calculated.By using the optimization toolbox of MATLAB software calculation method of counterweight parameters,an optimized model of bending moment has been developed.Besides,with the full-scale fatigue test data of a 40.3m blade,both the reliability of the model and the effectiveness of the calculation method are further proved.