Study On The Flutter Characteristics Of Transverse Traction Coupling Of Wire Rope In Wind Turbine Blade Static Test

With the development of wind power from land to sea,blades,as an important component of wind turbines,face great challenges in their structural and mechanical properties due to environmental changes.The static loading test of wind turbine blades can effectively test their performance,which is of great significance for improving the service performance of blades.At present,the loading method of lateral traction has been widely used in static loading tests because it does not need to consider the weight of blades and fixtures and is suitable for indoor loading.However,in the transverse traction static loading test,the wire rope used to transfer the load will flutter as the loading phase advances,and the coupling effect between different factors that cause flutter at a single loading point and between different loading points will occur due to flutter,resulting in increased coupling of flutter.Wire rope chatter not only affects the accuracy and synergy of static loading tests,but may even cause safety accidents and cause huge losses.In order to solve this problem,this paper first analyzes the wire rope loading system,establishes a mathematical model of wire rope flutter of a single loading unit and a mathematical model of coupling flutter of multiple loading units,determines the factors affecting the coupling flutter of wire rope and verifies the model,then conducts dynamic simulation,analyzes the influence of different factors on the flutter of the wire rope,determines the optimization direction of the static loading system,and finally conducts field test verification for the optimized loading equipment to ensure that the loading test can be carried out efficiently and accurately.The specific research content is as follows:(1)Aiming at the flutter problem of a single loading point in the static loading test,the mathematical models of the single-point single-rope loading system and the single-point pulley loading system were established with the longitudinal displacement of the transverse wire rope as the research object,and the longitudinal vibration expression of the wire rope in the two systems was derived based on the Hamiltion principle,and the vibration of the two systems under the conditions of boundless excitation and boundary-based excitation was analyzed.Finally,by applying the Galerkin weighted margin method,the nonlinear longitudinal vibration partial differential equations of the wire rope under various working conditions are discretized into a series of nonlinear ordinary differential equations,and the final expression is verified.(2)Aiming at the problem of wire rope coupling flutter between multiple loading points in the static loading test,the mathematical models of the double-point pulley loading system and the double-point hybrid loading system were established according to the different stiffness coefficients at different loading nodes of the blades and the difference in loading speed between the loading nodes,and the mathematical expression of the coupling flutter of the wire rope under the condition of unterminated excitation was obtained based on the Hamiltion principle,and finally the Galerkin method was used to discretize the partial differential equation of nonlinear longitudinal vibration.The longitudinal vibration acceleration curve of the vibration equation is compared with the experimental data to verify the effectiveness of the mathematical model.(3)Based on the blade static loading test equipment,the simulation model was reasonably simplified,the main factors affecting the flutter of the wire rope were selected according to the vibration equation expression,and the test group was designed;The ADAMS/Cable module and combined with the bushing force method are used to establish the dynamic simulation models of single-point and double-point wire rope systems,add drive,load and motion pairs to the model,set a reasonable simulation time and number of steps for dynamic simulation,and verify the effectiveness of the simulation model by comparing with the mathematical model results,and finally obtain the influence degree of different factors on the flutter of the wire rope by changing the parameters of the simulation model.(4)Based on the analysis results of dynamic simulation and the parameters of the field equipment,the optimization measures of the static loading equipment are proposed,and the effectiveness of the optimization measures is verified through field tests.