The constantly growing demand for cost-intensive lightweight structures is accompanied by an increased demand for reliable non-destructive testing (NDT) methods. Previous investigations have shown that Lamb Waves (LW) are very well suited for the use in Structural Health Monitoring (SHM) due to their relatively undamped propagation over long distances. Therefore the numerical modelling of a non-contact and automated system for non-destructive testing of C-FRP laminates was investigated in the present study. The method is based on the propagation of LW, which are excited by an actuator-driven piezo transducer and interact with defects in the structure. In contrast to classical Structural Health Monitoring, a scanning inspection system is used instead of a sensor permanently integrated into the structure to detect the measurement signals. For the representation of the wave propagation a three-dimensional simulation model with the commercial FEM software PZFlex was modelled. The wave interactions in defective C-FRP coupons are investigated and visualized through different output formats like A-, B- and C-Scans. Additionally the model allows the determination of the dispersion characteristics of the LW in the examined laminate. The validation of the numerical results was successfully carried out at different levels with the help of experimental investigations.

中文翻译：

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用于无损检测的 C-FRP 层压板中兰姆波传播及其与缺陷相互作用的数值模拟

随着对成本密集型轻型结构的需求不断增长，对可靠的无损检测 (NDT) 方法的需求也在不断增长。先前的调查表明，兰姆波 (LW) 非常适合用于结构健康监测 (SHM)，因为它们在长距离上相对无阻尼传播。因此，本研究对用于 C-FRP 层压板无损检测的非接触式自动化系统的数值建模进行了研究。该方法基于 LW 的传播，LW 由致动器驱动的压电换能器激发并与结构中的缺陷相互作用。与传统的结构健康监测相比，使用扫描检查系统代替永久集成到结构中的传感器来检测测量信号。为了表示波的传播，使用商业 FEM 软件 PZFlex 对三维仿真模型进行建模。通过不同的输出格式（如 A-、B- 和 C-扫描）研究和可视化有缺陷的 C-FRP 试样中的波相互作用。此外，该模型还可以确定所检查层压板中 LW 的色散特性。在实验研究的帮助下，数值结果的验证在不同层次上成功进行。此外，该模型还可以确定所检查层压板中 LW 的色散特性。在实验研究的帮助下，数值结果的验证在不同层次上成功进行。此外，该模型还可以确定所检查层压板中 LW 的色散特性。在实验研究的帮助下，数值结果的验证在不同层次上成功进行。