Carbon fiber reinforced plastic (CFRP) − Nomex adhesive honeycomb structures are widely used in aerospace due to their excellent properties. However, debonding defects pose a significant challenge to structural safety due to their hidden nature and high risk. In this work, to address the debonding detection in the CFRP-Nomex honeycomb structure, a method based on the zero group velocity (ZGV) feature is proposed. By calculating the dispersion curve of the structure, it is found that there is the ZGV on the branch. Further analysis revealed that this ZGV feature is generated by the repulsion between the and branches. The simulation and experimental analysis of the acoustic propagation characteristics in the honeycomb structure confirmed the presence of the ZGV feature with its energy localized near the exciting point. When debonding defects occur in the honeycomb structure, this feature disappears. Therefore, the ZGV feature can be used for the debonding detection of CFRP-Nomex honeycomb structures. Compared with ultrasonic C-scan, the results demonstrate that the proposed method can accurately detect and locate debonding defects with a diameter of 20 mm. Due to its simplicity, the method does not require sophisticated equipment or complex signal processing procedures, making it suitable for in-service inspection.

中文翻译：

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CFRP-Nomex蜂窝结构的零群速度特征及其在脱粘检测中的应用


碳纤维增强塑料 (CFRP) - Nomex 粘合蜂窝结构因其优异的性能而广泛应用于航空航天领域。然而，脱粘缺陷因其隐蔽性和高风险而对结构安全构成重大挑战。在这项工作中，为了解决 CFRP-Nomex 蜂窝结构中的脱粘检测问题，提出了一种基于零群速度（ZGV）特征的方法。通过计算结构的频散曲线，发现分支上存在ZGV。进一步分析表明，这种 ZGV 特征是由 和 分支之间的排斥力产生的。对蜂窝结构中声传播特性的模拟和实验分析证实了ZGV特征的存在，其能量集中在激励点附近。当蜂窝结构中出现脱粘缺陷时，该特征消失。因此，ZGV特征可用于CFRP-Nomex蜂窝结构的脱粘检测。与超声波C扫描相比，结果表明该方法可以准确地检测和定位直径为20 mm的脱粘缺陷。由于该方法简单，不需要复杂的设备或复杂的信号处理程序，适合在役检查。