| Wind power generation technology is gradually replacing the original energy type,and has become the new technology of power generation that people all over the world pay attention to.However,due to the variable wind speed in nature,it will cause the excitation effect to the wind turbine,causing the wind turbine to produce flutter and resonance to form fatigue damage.At present,the service life of wind turbine is generally lower than its design life.However,the research on the dynamic response of wind turbine is relatively less affected by airfoil and blade material.Therefore,it is of great significance to explore the dynamic structure characteristics and influence factors of wind turbine blade airfoil and material to the safe operation of the wind turbine.Firstly,the blade of NACA4415 airfoil and epoxy FRP material is selected to analyze the influence of density,elastic modulus and Poisson's ratio on natural frequencies.The modal performance of a S airfoil with wood and PLA as material is studied,and the material that is more suitable for wind turbine blade is calculated and analyzed.At the same time,based on this material,the modal analysis of the blade with uneven mass distribution is carried out,and the dynamic frequency diagram and stress cloud chart are obtained.Then,the reasonable improvement plan of blade structure is put forward from the aspects of natural frequency and dynamic frequency characteristics.This paper relies on a large number of numerical simulation calculation experience and related literature at home and abroad to prove that the analysis method is reasonable.In this paper,the modal analysis method is used to analyze the material property factors that affect the modal performance of wind turbine blades by numerical simulation.The results show that Poisson's ratio has little effect on the vibration frequencies of the blades,and the elastic modulus and density have great influence on the vibration frequencies.Then,through the comparison and analysis of the natural frequency,dynamic frequency and the stress response characteristics of the two materials of a S airfoil,it is found that the PLA material is more suitable for the wind turbine analyzed.Furthermore,the modal properties of the PLA material with different mass distribution are analyzed.The results show that the blade with large tip mass can effectively reduce the natural frequency of each order of the wind wheel,and effectively change the dynamic frequency of each order to get rid of the resonance region quickly;the natural frequency of the high quality blade in the middle is higher than that of the tip of the blade.Comparing the dynamic frequency curves between the two and three segment blades,it is found that there is no correlation between the number of segments and the dynamic frequency characteristics;the natural frequency of the two stage blade is lower and the stress at the maximum response frequency is smaller.Finally,the modal analysis of the NACA4415 airfoil using the same material is carried out,and it is found that the influence of airfoil on modal performance of the blade is not obvious.According to the above research conclusions,when the blade is improved from the natural frequency and the dynamic frequency characteristics,the quality of the blade tip should be increased properly under the condition that the blade root strength is not affected,and it is beneficial to improve the modal performance of the blade.In this paper,the influence factors of material properties on modal performance of wind turbine blades are investigated by numerical simulation.The related research results can provide a direct and important basis for the influence of material properties on modal performance,and also provide a theoretical reference for blade structure design. |
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