Study On Influence Factors Of Large Wind Turbine Blade Inter Layer Crack

The coordinate system of wind turbine motion and the coordinate transformation formula after the tremor and torsion is built with the basis of A simplified model for the bending motion of a straight bar with one end fixed and the other free,as the dynamic characteristics of the blades by analysis.The kinematic analysis of the blade's shaking and flapping motion is carried out.The displacement equation and vibration model are established based on the pendulum and flapping motion.The displacement equation of blade surface is deduced and the relation formula between K and G is established.In order to verify the correctness of the model and formula established,considering the characteristics of the blade material are analyzed and the flapping motion of pendulum shock force effects,using ADAMS and ANSYS software to simulate the kinematics and dynamics simulation,and through XTDIC 3D deformation strain measurement and analysis system by digital speckle correlation method and strain experiment the comparative analysis of related data.According to the type of open type displacement,displacement,strain and stress of sliding surface of composite blade in any section of a shimmy motion is intronduced,a strain displacement and stress-strain relationship of the balance equation.The influence of vibration and wave motion on interlaminar fracture toughness,The orthogonal blade laying(0/Core/0)structure is set up,and the calculation conditions of displacement and stress are established.The method for calculating the stress intensity factor of the interlaminar crack of composite blade is derived,and the relationship between the stress intensity factor and the energy release rate is derived.In this paper,the curvature,displacement,strain and stress of the pendulum are analyzed by using the theoretical method.ANSYS software was used for numerical simulation to study the stress response of the lower layer under different impact velocity.The relationship between the displacement and stress strain is verified by the dynamic vibration test and the drop hammer impact test.On the basis of the original platform in the laboratory,the experiment system of swing and sway displacement strain is improved.The increase in the original layout of the strain sensor displacement strain detection system,fixed detection range displacement strain of the original small defects of low accuracy,can better achieve the modal displacement velocity strain test force model,theory and algorithm.The leaves at different rates of interlaminar fracture,static by CMT5205 electronic universal mechanical testing machine stress experiment,compared the composite blade crack growth angle and length,and provides a theoretical basis for the inspection of the tremor movement and the stress intensity factor and the energy release rate.The influence of the shaking and flapping motion of the flexible blades on the interlaminar fracture toughness is given.It provides a strong theoretical basis for the design of the blade structure and the fault analysis of the large wind turbine in the future.