摘要
针对大型轻型柔性叶片存在的几何非线性变形情况,基于几何精确梁理论建立了非线性叶片梁单元,考虑了叶片预弯预扭、各向异性、变形耦合以及截面偏心的特点。对非线性结构方程的数值求解方法进行了探讨。结合动量叶素理论建立了可用于分析叶片大变形动态响应问题的几何非线性气弹模型。通过两个算例验证了结构模型的正确性。以NREL 5MW风力机叶片为研究对象,分析了叶片静态变形、固有频率、以及在阵风、偏航错误条件下的动态响应,并与FAST计算结果进行了对比,结果表明,在静态变形范围内几何非线性气弹模型与FAST非常好的吻合,进一步验证了该模型计算正确性。通过降低叶片截面弯曲刚度,发现在叶片大变形时,几何非线性气弹模型可以获得更准确的结果。
To study the higher nonlinear behavior introduced by larger,lighter and more flexible wind turbine blade,an aero-elastic model with geometrically nonlinear beam is developed in this paper. The nonlinear beam based on geometrically exact beam theory contains the effects respectively of pre-bending,pre-twisting and eccentric shape. BEM theory is used because of its efficiency. The structure model is validated by two simulation cases. The static deflections of NREL 5MW offshore wind turbine blade show good agreement with results obtained by FAST.The natural frequencies and the responses under gust and yaw error conditions are also simulated. The responses of blade with reduced stiffness show more exactly results of the geometrically nonlinear aero-elastic model rather than the linear model.
出处
《机械科学与技术》
CSCD
北大核心
2015年第12期1805-1812,共8页
Mechanical Science and Technology for Aerospace Engineering
基金
中央高校基本科研业务费专项基金项目(3102015BJ(Ⅱ)CG015)资助
关键词
风力机叶片
几何非线性
几何精确梁
大变形
acceleration
aeroelasticity
angle of attack
angular velocity
beams and girders
computational efficiency
computer simulation
computer software
deftection(structures)
efficiency
errors
geometry
mathematical models
matrix algebra
momentum
natural frequencies
Nonton-Rophson method
stiffness
structural dynamics
turbomachine blades
velocity
Weibull distribution
geometrically exact beam
geometrically nonlinear effect
large deflection
wind turbine blade
