Abstract Impact fatigue caused by rain droplets, also called rain erosion, is a severe problem for wind turbine blades and aircraft. In this work, an assessment of impact fatigue on a glass fibre reinforced polymer laminate with a gelcoat is presented and the damage mechanisms are investigated. A single point impact fatigue tester is developed to generate impact fatigue damage and SN data. Rubber balls are repeatedly impacted on a single location of the coated laminate. Each impact induces transient stresses in the coated laminate. After repeated impacts, these stresses generate cracks, leading to the removal of the coating and damage to the laminate. High-resolution digital imaging is used to determine the incubation time until the onset of coating damage, and generate an SN curve. An acoustic emission sensor placed at the back of the laminate monitors changes in acoustic response as damage develops in the coated laminate. The subsurface cracks are studied and mapped by 3D X-ray computed tomography. A finite element method model of the impact shows the impact stresses in the coating and the laminate. The stresses seen in the model are compared to cracks found by 3D tomography. The damage is also evaluated by ultrasonic scanning.

中文翻译：

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涂层玻璃纤维增​​强聚合物层压板的冲击疲劳损伤

摘要 由雨滴引起的冲击疲劳，也称为雨蚀，是风力涡轮机叶片和飞机面临的严重问题。在这项工作中，对带有凝胶涂层的玻璃纤维增​​强聚合物层压板进行了冲击疲劳评估，并研究了损坏机制。开发了单点冲击疲劳试验机以生成冲击疲劳损伤和 SN 数据。橡胶球反复撞击涂层层压板的单个位置。每次冲击都会在涂层层压板中引起瞬态应力。在反复冲击后，这些应力会产生裂纹，导致涂层脱落和层压板损坏。高分辨率数字成像用于确定直到涂层损坏开始的孵化时间，并生成 SN 曲线。放置在层压板背面的声发射传感器会随着涂层层压板损坏的发展监测声学响应的变化。地下裂纹通过 3D X 射线计算机断层扫描进行研究和绘制。冲击的有限元方法模型显示了涂层和层压板中的冲击应力。模型中看到的应力与 3D 断层扫描发现的裂缝进行了比较。损伤也通过超声波扫描来评估。