Abstract

The load-carrying component of wind turbine blades is a composite box beam that often consists of two spar caps and two shear webs. Local buckling of such beams usually leads to failure of spar caps and/or shear webs. As the failure modes change with cross-sectional geometries and load conditions, it is of interest to develop a method for efficient structural failure evaluation. As a correlation exists between linear buckling response and the potential structural failure, this study presents comprehensive numerical studies on the box beams with different external shapes and layer thicknesses to establish buckling mode maps that can be useful for the preliminary structural design. The results show that the changes of cross-sectional aspect ratio affect the buckling strength more than the change of the weight or the material usage when the spar cap buckling dominates the failure. Larger curvature of spar caps can significantly improve the buckling strength due to better resistance to the cross-sectional flattening. The evaluation method only uses the modeling techniques readily available in common commercial FE software, and no in-house user subroutines is needed, thus allowing the failure evaluation to be performed efficiently in the early design of the load-carrying box beams in wind turbine blades.

中文翻译：

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评估不同几何形状和荷载条件下承重复合箱梁的结构破坏

摘要

风力涡轮机叶片的承载部件是复合箱形梁，通常由两个翼梁盖和两个抗剪腹板组成。这种梁的局部屈曲通常导致翼梁帽和/或抗剪腹板的破坏。随着失效模式随横截面几何形状和载荷条件的变化而变化，开发一种有效的结构失效评估方法是很有意义的。由于线性屈曲响应与潜在的结构破坏之间存在相关性，因此本研究对具有不同外部形状和层厚度的箱形梁进行了全面的数值研究，以建立可用于初步结构设计的屈曲模式图。结果表明，当翼梁帽屈曲主导失效时，截面纵横比的变化对重量的影响比对重量或材料用量的变化影响更大。翼梁帽的较大曲率由于对横截面变平的更好抵抗而可以显着提高屈曲强度。该评估方法仅使用常见的商用有限元软件中容易获得的建模技术，并且不需要内部用户子例程，因此可以在风轮机叶片中的承重箱形梁的早期设计中有效地执行故障评估。 。