[关键词]
[摘要]
为了研究温度对风力机叶片固有频率的影响,文章以2 kW小型风力机叶片为研究对象,首先通过理论分析得到温度变化引起材料弹性模量和结构状态发生改变,从而使得叶片频率发生变化。然后采用有限元数值模拟和模态试验的方法对影响因素进行研究,得出叶片固有频率随温度变化规律。结果表明,环境温度变化使得材料弹性模量改变对叶片固有频率的影响远大于结构状态改变产生的影响;温度在-20 ℃~30℃的变化时,随着温度的升高,叶片前四阶固有频率逐渐降低,两者变化呈线性关系,与20℃时相比,各阶频率变化率在4.18%~5.23%之间;通过最小二乘法得出的前四阶固有频率随温度变化的线性拟合方程,可以为基于振动检测技术对叶片覆冰状态检测、叶片损伤情况评估等提供参考。
[Key word]
[Abstract]
To investigate the influence of temperature on the natural frequency of wind turbine blades, the 2 kW small wind turbine blade is taken as the research object in this paper, Firstly, the theoretical analysis shows that the temperature change causes the elastic modulus and structural state of the material to change, so that the blade frequency changes.The influencing factors of the blade frequency are studied by the numerical simulation and modal test methods, and the variation rules of blade frequency at different temperatures is obtained. The results show that the influence of the change of material elastic modulus on the natural frequency of the blade is much greater than that of the structural state change due to the change of environmental temperature.When the temperature varies from-20 ℃ to 30 ℃, the first four natural frequencies of the blade gradually decreases while the temperature increases, the variation rule of the natural frequencies and temperature are a linear relationship.Compared with 20 °C, the frequency change rate of each order is between 4.18 % and 5.23 %.The linear fitting equation of the first four-order natural frequency with temperature is obtained by the least square method,which can provide a reference for the detection of blade icing state and the evaluation of blade damage based on vibration detection technology.
[中图分类号]
TK83
[基金项目]
国家自然科学(11262015);内蒙古农业大学优秀青年科学(2014XYQ-9)