Study On The Stress/strain Characteristics Of Wind Turbine Blades Based On Fluid-solid Couplings

Wind rotor is a key part of wind turbine.Blades of wind turbine are slender bodies of high deflection.They undergo a great deformation under aerodynamic loading.This kind of unsteady deformation is inter-coupled with unsteady aerodynamic loading,which not only changes aerodynamic performance of wind turbines,but affect operating safety.Structural design and material of blades of wind turbine depends on its bearing loads and stress/strain responses.Especially in the circumstance that unit capacity of wind turbines becomes higher and higher,fluid-solid coupling based study on stress and strain characteristics of blades of wind turbines has become a key point to be emphasized in design of wind turbine.In this paper,the author took horizontal axis wind turbine with a diameter of 2m as an object of study,discussed the physical problem of interaction between structural loads and stress/strain response of blades of wind turbine,and adopted such methods as calculation of numerical simulation and experimental study to research stress/strain characteristics of blades of wind turbine when they bear various loads.The main research contents include:(1)Model the blade with SolidWorks,which is a three-dimension modeling software and establish bi-directional fluid-solid coupling calculation platform with Ansys Workbench to generate meshes of the blade model and conduct unsteady calculation.By regulating rotating speed,we can get concrete values of flow field and structure field under different loads,and research displacement and stress/strain of blades under different conditions quantitatively.The results show that aerodynamic loading makes the blade deform in the swing direction and have a great displacement spanwise;there is a positive correlation between rotating speed and shimmy of blades on the circular motion plane,but affected by gravitational load and rotating direction,stress/strain of the blade has a periodical change when it is located at different positions(2)Using digital image technologies and Vic-3D non-contact type displacement and strain measuring system to measure displacement and stress/strain of the blade at different rotating speeds and different locations under gravitational load and inertial load.Analyze the displacement and stress/strain based on the testing data,and we can obtain: the influence law between the inertial load and stress/strain of the blade,and the relation between gravitational load and stress/strain of the blade when it is located at different positions during circular motion.The author discussed spanwise and chordwise displacement and distribution of stress/strain of the blade of wind turbine when multiple loads are applied simultaneously.The study provides reference and guide for design,operation and maintenance of wind turbines.