Stanciu Mariana Domnica, Nastac Silviu Marian, Tesula Ionut
Faculty of Mechanical Engineering, Transilvania University of Brașov, B-dul Eroilor 29, 500360 Brașov, Romania.
Mining and Metallurgical Section, Russian Academy of Natural Sciences, Sivtsev Vrazhek 29/16, 119002 Moscow, Russia.
Polymers (Basel). 2022 Apr 4;14(7):1471. doi: 10.3390/polym14071471.
The structure of wind turbine blades (WTBs) is characterized by complex geometry and materials that must resist various loading over a long period. Because of the components' exposure to highly aggressive environmental conditions, the blade material suffers cracks, delamination, or even ruptures. The prediction of the damage effects on the mechanical behavior of WTBs, using finite element analysis, is very useful for design optimization, manufacturing processes, and for monitoring the health integrity of WTBs. This paper focuses on the sensitivity analysis of the effects of the delamination degree of fiberglass-reinforced polymer composites in the structure of wind turbine blades. Using finite element analysis, the composite was modeled as a laminated structure with five plies (0/45/90/45/0) and investigated regarding the stress states around the damaged areas. Thus, the normal and shear stresses corresponding to each element of delaminated areas were extracted from each ply of the composites. It was observed that the maximum values of normal and shear stresses occurred in relation to the orientation of the composite layer. Tensile stresses were developed along the WTB with maximum values in the upper and lower plies (Ply 1 and Ply 5), while the maximum tensile stresses were reached in the perpendicular direction (on the thickness of the composite), in the median area of the thickness, compared to the outer layers where compression stresses were obtained. Taking into account the delamination cases, there was a sinuous-type fluctuation of the shear stress distribution in relation to the thickness of the composite and the orientation of the layer.
风力涡轮机叶片（WTB）的结构具有复杂的几何形状和材料特性，这些材料必须长期抵抗各种载荷。由于部件暴露在极具侵蚀性的环境条件下，叶片材料会出现裂纹、分层甚至破裂。使用有限元分析来预测损伤对风力涡轮机叶片力学行为的影响，对于设计优化、制造工艺以及监测风力涡轮机叶片的健康完整性非常有用。本文重点研究了风力涡轮机叶片结构中玻璃纤维增强聚合物复合材料分层程度影响的敏感性分析。通过有限元分析，将复合材料建模为具有五层（0/45/90/45/0）的层合结构，并研究了损伤区域周围的应力状态。因此，从复合材料的每一层中提取分层区域每个单元对应的正应力和剪应力。观察到正应力和剪应力的最大值与复合材料层的取向有关。沿风力涡轮机叶片产生拉应力，在上层和下层（第1层和第5层）出现最大值，而与获得压应力的外层相比，在厚度的中间区域，垂直方向（在复合材料厚度上）达到最大拉应力。考虑分层情况，剪应力分布相对于复合材料厚度和层的取向呈现出正弦型波动。
