The use of composite plate structures has become increasingly prevalent in industries such as civil engineering, aerospace, high-speed rail, automotive, and wind power. However, the propagation of ultrasonic Lamb waves in these structures is subject to multi-modal and frequency dispersion effects, which, coupled with the complicated anisotropic propagation mechanism of composite materials, makes it challenging to extract damage scatter signals without a health signal as a reference. In this study, we apply the frequency-wavenumber ( f- k) domain filter wavefront modal method to carbon fiber reinforced polymer (CFRP) materials and use a three-dimensional (3D) window function to achieve different modalities and their corresponding damage reflection signals in the absence of a reference dispersion curve. Single modal damage imaging is achieved using a common source method (CSM) by laser vibration scanning experiment. To effectively extract single modalities in laminate material damage detection, a 3D filter window function was constructed. Considering the skew angle correction, it can effectively remove the direct wave signal, so as to realize the imaging of the damage.

中文翻译：

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研究层压复合材料fk域激光扫描损伤检测方法

复合材料板结构的使用在土木工程、航空航天、高铁、汽车、风电等行业中越来越普遍。然而，超声兰姆波在这些结构中的传播受到多模态和频率色散效应的影响，再加上复合材料复杂的各向异性传播机制，使得在没有健康信号作为参考的情况下提取损伤散射信号具有挑战性。在本研究中，我们将频率-波数（f-k）域滤波器波前模态方法应用于碳纤维增强聚合物（CFRP）材料，并使用三维（3D）窗函数来获得不同模态及其相应的损伤反射信号在没有参考色散曲线的情况下。通过激光振动扫描实验，采用共源法（CSM）实现单模态损伤成像。为了有效地提取层压材料损伤检测中的单一模态，构建了 3D 滤波器窗口函数。考虑斜角校正，可以有效去除直达波信号，从而实现损伤的成像。