风力机叶片尾缘黏接线处理对尾缘胶接剪切疲劳性能的影响研究

Influence of bonding line treatments on the shear fatigue damage of the blade trailing-edge adhesive joint

随着风力发电机正朝着大型化和海洋化的方向发展,风力机叶片设计得越来越长,叶片的替换和停机造成的经济损失也将越来越高。然而,大量的实际观测调查统计发现很多叶片损伤问题是由于叶片的尾缘黏接开裂造成的。叶片尾缘的几何外形不规则性、生产技术局限性和运行环境的复杂性,使得叶片尾缘的黏接对缺陷和损伤更加敏感。传统的设计方法和试验研究,由于简化假设和成本的原因,并不是非常适合于精确研究风力机叶片尾缘黏接的疲劳损伤问题。以风力机叶片尾缘构型为研究对象,评估各种尾缘黏接线处理方式对尾缘胶接剪切疲劳性能的影响。尾缘黏接线的处理方式主要包括尾缘黏接线起点的倒角形式和尾缘黏接线终点的外包边。叶片的结构模型采用有限单元法进行仿真,其中叶片层合板结构采用壳单元进行仿真,尾缘黏接的结构胶采用实体单元进行仿真。采用标准试验件测试得到结构胶的疲劳性能。采用有限单元法和应力转换矩阵方法计算叶片结构中尾缘胶接的疲劳损伤。分析结果显示,叶片尾缘的结构构型对尾缘胶接的损伤分布有明显的影响,并且该研究结果对风力机叶片结构设计、叶片生产和叶片维修有指导意义。

Wind turbines are under continuous development for large-scale deployment and oceanization, leading to the requirement for longer blades. Many blade issues originate from the cracking of the blade trailing edge. The edge is more susceptible to damage due to the complex geometry, manufacturing technique, and operation conditions.However, the traditional design method and the expensive experimental research are not suitable for the accurate damage analysis of the trailing-edge adhesive because of simplifying assumptions and costs. This study aimed to investigate the influence of trailing-edge structural configurations on the shear fatigue life of the trailing-edge adhesive joint using finite element and stress transformation matrix(STM) methods. The structural configurations of the blade trailing edge included the position of unidirectional fiber layer(UD), chamfer of bonding line,prefabricated components, and outer over-lamination of the trailing edge. In this study, the finite element method was used to simulate the blade structure. The shell element was used for laminates, and the solid element was used for the trailing-edge adhesive joint. The basic shear fatigue properties of the adhesive were obtained by standard component tests. The shear fatigue life of the blade trailing-edge adhesive joint under given load conditions was calculated using the fatigue properties of the adhesive and STM method. The results showed that the angle of chamfering, location of UD, rigidity of the preform, and outer over-lamination all obviously affected the fatigue damage of trailing-edge adhesive. The findings of this study can be used to guide blade structure design and blade production and maintenance.