风力机叶片截面主刚度系数与横向剪应力分析

An Analysis of Main Stiffness Coefficient and Transverse Shear Stress of Wind Turbine Blade Section

针对风力机复合材料叶片弯曲与扭转刚度计算,以及当叶片在横向剪力作用下对空心薄壁截面上剪应力的数值计算方法进行研究。现代风力机叶片呈细长扭曲形,翼型截面为薄壁且内部拓扑构型复杂,材料具有各向异性。在应用各类梁模型进行叶片气弹计算和强度校核等力学分析时,叶片截面的刚度系数和截面剪应力分布是必需参数。基于复合材料薄壁结构层合理论和加权平均方法,结合Bredt-Batho剪力理论,考虑了复合材料叶片的剪切腹板效应和翘曲效应,建立了复合材料层合板等效弹性常数与截面刚度系数数值分析算法;根据弹性力学板壳理论,考虑横向剪切和截面翘曲对截面变形的影响,建立了横向剪力引起的剪力流数值计算方法,并开发了相关算法的Matlab程序。分析10 MW风力机叶片主刚度系数和剪力流分布,并对比文献结果,验证了模型的正确性和算法的有效性。

This paper studies the calculation of bending and torsional stiffness of wind turbine composite blades,as well as the numerical calculation method of shear stress on the hollow thin-walled section when the blade is subjected to transverse shear force.Modern wind turbine blades are slender and twisted,with thin-walled airfoil sections and complex internal topological configurations,and the materials are anisotropic.When applying various beam models for mechanical analysis such as blade aeroelastic calculation and strength check,the stiffness coefficient of the blade section and the calculation results of the section shear stress distribution are required parameters.Based on the composite thin-walled structure lamination theory and weighted average method,combined with the Bredt-Batho shear theory,a numerical analysis algorithm for the equivalent elastic constant and section stiffness coefficient of the composite laminate was established,taking into account the shear web effect of the composite blade.and warping effects;based on the plate and shell theory of elastic mechanics and considering the influence of transverse shear and section warpage on section deformation,a numerical calculation method for shear flow caused by transverse shear was established;a Matlab program for related algorithms was developed.By analyzing the main stiffness coefficient and shear flow distribution of a 10 MW wind turbine blade and comparing the literature results,the correctness of the model and the effectiveness of the algorithm are verified.