Condition monitoring, nondestructive testing, and fault diagnosis are currently considered crucial processes for on-condition maintenance (OCM) to increase the reliability and availability of wind turbines and reduce the wind energy generation cost. Carbon fiber reinforced plastics (CFRPs) have been increasingly used to fabricate wind turbine blades. Delamination-type damage is inevitable during manufacture or in-service of a CFRP blade. This inner (subsurface) flaw, usually difficult to be detected by artificial visual inspection or machine vision based on CCD or CMOS, severely degrades the load-bearing capacity of a blade. Induction infrared thermography (IIT) is an emerging infrared machine vision inspection technology, which has the capability of insight to CFRP based on electromagnetic induction and heat conduction. This paper introduces photothermal thermal-wave radar (TWR) nondestructive imaging (NDI) to IIT, based on cross-correlation (CC) pulse compression and matched filtering and applies TWR principles to CFRP imaging inspection and diagnosis. The experimental studies carried out under the transmission mode have shown that TWR B-scan and phasegram can be used to inspect and diagnose subsurface delaminations in CFRP with improved signal-to-noise ratio (SNR) and shape identification. As a new machine vision inspection method, TWRI will play an important role in the OCM of the wind turbine blade.

中文翻译：

---

用于叶片复合材料成像检查和诊断的感应红外热成像和热波雷达分析


状态监测、无损检测和故障诊断目前被认为是状态维护（OCM）的关键过程，以提高风力涡轮机的可靠性和可用性并降低风能发电成本。碳纤维增强塑料（CFRP）越来越多地用于制造风力涡轮机叶片。在 CFRP 叶片的制造或使用过程中，分层型损坏是不可避免的。这种内部（表面下）缺陷通常难以通过人工目视检查或基于 CCD 或 CMOS 的机器视觉检测到，严重降低了叶片的承载能力。感应红外热成像（IIT）是一种新兴的红外机器视觉检测技术，具有基于电磁感应和热传导的碳纤维复合材料的洞察能力。本文将基于互相关（CC）脉冲压缩和匹配滤波的光热热波雷达（TWR）无损成像（NDI）引入IIT，并将TWR原理应用于CFRP成像检查和诊断。在透射模式下进行的实验研究表明，TWR B 扫描和相图可用于检查和诊断 CFRP 的地下分层，并具有改进的信噪比（SNR）和形状识别能力。 TWRI作为一种新的机器视觉检测方法，将在风电叶片的OCM中发挥重要作用。