Detection of a Single Transverse Crack in a CFRP Cross-ply Laminate by Visualizing Mode Conversion of Lamb Waves
Detection of a Single Transverse Crack in a CFRP Cross-ply Laminate by Visualizing Mode Conversion of Lamb Waves
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DOI：
10.1016/j.compstruct.2021.115118
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发表时间：
2021-12
影响因子：
6.3
通讯作者：
Fengming Yu;O. Saito;Y. Okabe
中科院分区：
文献类型：
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作者：
Fengming Yu;O. Saito;Y. Okabe
横向裂纹（TC）的检测对于建立可靠的结构健康监测（SHM）和无损检测（NDI）以在早期阶段警告碳纤维增强塑料（CFRP）结构中可能发生的大规模损伤是重要的。在这项研究中，建立了一个诊断方法，是敏感的一个单一的TC可视化激光诱导超声波在正交铺设CFRP层压板。首先，使用谐波振荡的有限元分析（FEA）澄清了TC诱导的模式转换的层合板中的现象。这种有限元方法是明确的和精确的研究在裂纹板的各个模式的转换行为。然后，通过另一个基于有限元分析的脉冲激光超声模拟，验证了这种转换现象。最后，为了观察实际中的模式转换现象，我们用激光超声可视化检测仪（LUVI）进行了实验。LUVI系统可以可视化的波传播的二维（2D）波场形成的表面上的CFRP正交铺设层压板与单一的TC。通过观察波传播的图像结果，我们验证了A0模式的波分量是从S0模式转换在TC，即使转换的A0模式具有比入射的S0模式在正交铺设CFRP层压板的振幅小得多。因此，这些可视化结果可以用于可靠地检测CFRP正交铺设层合板中的单个TC。
Detection of transverse crack (TC) is important in establishing reliable structural health monitoring (SHM) and nondestructive inspection (NDI) for warning the potential occurrence of large-scale damage in carbon fiber reinforced plastic (CFRP) structures at an earlier stage. In this research, a diagnostic method that is sensitive to a single TC was established by visualizing laser-induced guided ultrasonic waves in a cross-ply CFRP laminate. First, the phenomenon of TC-induced mode conversion in the laminate was clarified using finite element analysis (FEA) of harmonic oscillations. This FEA method is explicit and precise for investigating the conversion behavior of individual modes in a cracked plate. Then, the conversion phenomenon was also validated by another FEA-based pulse laser ultrasonic simulation. Finally, to observe the mode conversion phenomenon in practice, we conducted an experiment with a laser ultrasonic visualizing inspector (LUVI). The LUVI system could visualize the wave propagation in a two-dimensional (2D) wavefield that was formed on the surface of the CFRP cross-ply laminate with a single TC. By observing the image results of wave propagation, we verified that the wave component of the A0mode was converted from the S0mode at a TC even though the converted A0mode had a much smaller amplitude than the incident S0mode in the cross-ply CFRP laminate. Thus, those visualization results could be used to detect a single TC in the CFRP cross-ply laminate reliably.