Wrinkle measurement in glass-carbon hybrid laminates comparing ultrasonic techniques: A case study
Wrinkle measurement in glass-carbon hybrid laminates comparing ultrasonic techniques: A case study
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DOI：
10.1016/j.compositesa.2018.08.014
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发表时间：
2018-11
期刊：
影响因子：
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通讯作者：
B. Larrañaga-Valsero;Robert A. Smith;R. Tayong;A. Fernández-López;A. Güemes
中科院分区：
文献类型：
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作者：
B. Larrañaga-Valsero;Robert A. Smith;R. Tayong;A. Fernández-López;A. Güemes
不幸的是，皱纹（也称为面外波纹）是一种常见的现象，导致一些风力涡轮机叶片意外失效。能够在工厂中检测到褶皱将降低灾难性故障的风险，并且表征褶皱将最小化修复面积，从而提高修复和设计的效率。这项工作比较了三种不同的超声技术的有效性，用于检测和表征的典型的玻璃-碳混合层压板，用于风力涡轮机叶片的平面外皱纹。测试样品的制造使得层压材料和缺陷代表风力涡轮机工业中使用的那些。进行基本的机械测试以检查由于起皱而导致的机械性能下降。理想的探头频率被确定为使用分析超声波传播模型的层片的共振频率。使用的三种不同的超声技术是：全矩阵捕获（FMC）与总聚焦方法（TFM），一个商业相控阵仪器和一个光栅扫描的单元素聚焦探头的浸泡测试。在可能的情况下，在超声波图像上测量皱纹的严重性参数，并与实际样品的测量结果进行比较，以确定哪种方法最能表征这种皱纹，哪种方法更适合在工业环境中实施。并不是所有的技术都允许充分表征标本上的平面外波纹。FMC/TFM方法给出了更好的结果，而相控阵技术和单元件浸没测试提出了更多的挑战。使用具有角度相关速度校正的自适应TFM方法实现了对TFM成像的额外增强。
Wrinkles, (also known as out-of-plane waviness) are, unfortunately, a common phenomenon that has caused some wind-turbine blades to unexpectedly fail in service. Being able to detect the wrinkles while in the factory will reduce the risk of catastrophic failure and characterising the wrinkles would minimise the repaired area, thus increasing the efficiency of the repair and the design. This work compares the effectiveness of three different ultrasound techniques for detecting and characterising out-of-plane wrinkles in the typical glass-carbon hybrid laminates that are used for wind-turbine blades. The tests samples were manufactured so that the laminates and the defects are representative of those used in the wind-turbine industry. Basic mechanical tests were performed to check the drop in mechanical properties due to wrinkling. The ideal probe frequency was determined as the resonance frequency of the plies using an analytical ultrasonic-propagation model. The three different ultrasound techniques used are: full-matrix capture (FMC) with the total focusing method (TFM), a commercial phased-array instrument and an immersion test with a raster-scanned single-element focused probe. When possible, severity parameters of the wrinkle were measured on the ultrasonic images and compared with the measurements of the actual sample in order to determine which method best characterises such wrinkles and which would be more appropriate to implement in an industrial environment. Not all of the techniques allowed full characterisation of out-of-plane waviness on the specimens. The FMC/TFM method gave better results whilst phased-array technology and single-element immersion testing presented more challenges. An additional enhancement to the TFM imaging was achieved using an Adapted-TFM method with an angle-dependent velocity correction.