Pasadas Dario J, Barzegar Mohsen, Ribeiro Artur L, Ramos Helena G
Instituto de Telecomunicações, Instituto Superior Técnico, Universidade de Lisboa, 1049-001 Lisbon, Portugal.
Sensors (Basel). 2024 Sep 13;24(18):5932. doi: 10.3390/s24185932.
Carbon fiber reinforced plastic (CFRP) is a composite material known for its high strength-to-weight ratio, stiffness, and corrosion and fatigue resistance, making it suitable for its use in structural components. However, CFRP can be subject to various types of damage, such as delamination, matrix cracking, or fiber breakage, requiring nondestructive evaluation to ensure structural integrity. In this context, damage imaging algorithms are important for assessing the condition of this material. This paper presents signal and image processing methods for delamination characterization of thin CFRP plates using eddy current testing (ECT). The measurement system included an inductive ECT probe with three coil elements, which has the characteristic of allowing eddy currents to be induced in the specimen with two different configurations. In this study, the peak amplitude of the induced voltage in the receiver element and the phase shift between the excitation and receiver signals were considered as damage-sensitive features. Using the ECT probe, C-scans were performed in the vicinity of delamination defects of different sizes. The dimensions and shape of the ECT probe were considered by applying the erosion method in the damage imaging process. Different thresholding approaches were also investigated to extract the size of the defective areas. To evaluate the impact of this application, a comparison is made between the results obtained before and after thresholding using histogram analysis. The evaluation of damage imaging for three different delamination sizes is presented for quantitative analysis.
碳纤维增强塑料（CFRP）是一种复合材料，以其高比强度、刚度以及耐腐蚀和抗疲劳性能而闻名，使其适用于结构部件。然而，CFRP可能会受到各种类型的损伤，如分层、基体开裂或纤维断裂，这就需要进行无损评估以确保结构完整性。在这种情况下，损伤成像算法对于评估这种材料的状况很重要。本文提出了使用涡流检测（ECT）对薄CFRP板的分层特征进行信号和图像处理的方法。测量系统包括一个带有三个线圈元件的感应式ECT探头，其特点是能够以两种不同配置在试样中感应出涡流。在本研究中，将接收元件中感应电压的峰值幅度以及激励信号和接收信号之间的相位差视为损伤敏感特征。使用ECT探头，在不同尺寸的分层缺陷附近进行了C扫描。在损伤成像过程中应用腐蚀方法时考虑了ECT探头的尺寸和形状。还研究了不同的阈值处理方法以提取缺陷区域的大小。为了评估该应用的影响，使用直方图分析对阈值处理前后获得的结果进行了比较。给出了三种不同分层尺寸的损伤成像评估结果以进行定量分析。
