Department of Civil and Architectural Engineering and Mechanics, University of Arizona, Tucson, AZ 85721, USA.
Department of Civil and Architectural Engineering and Mechanics, University of Arizona, Tucson, AZ 85721, USA; Pacific Waves NDT, LLC, Tucson, AZ 85716, USA.
Ultrasonics. 2022 Feb;119:106620. doi: 10.1016/j.ultras.2021.106620. Epub 2021 Oct 16.
An improved technique for sensing damage initiation and progression in thermoplastic resin composite plate specimens is presented in this study. The composite plate specimens are investigated by using a nonlinear ultrasonic (NLU) technique called Sideband Peak Count Index or SPC-I. The technique presented in this paper is an improvement from the previous SPC-I technique. This improved technique provides more reliable and consistent results and can monitor the damage progression over a wide range. In this paper the narrow band SPC-I technique is introduced to replace the conventional wide band SPC-I technique. The method implemented here is improved in three ways. First and foremost the narrow band SPC-I technique is introduced. Secondly, the non-permanently adhered gel coupled Lead-Zirconate-Titanate (PZT) transducers are used to reduce inconsistency in transducer adhesion and manufacturing. Lastly, higher sampling rate equipment is used for better signal resolution and peak counting. The experiments are performed on 4 sets of composite plate specimens fabricated using two composite fiber materials (Glass and Basalt) that have increasing levels of damage. The composite plate specimens were damaged by a falling weight impact machine with increasing impact energy (0 J, 10 J, 20 J and 30 J). The composite plate specimens were examined by propagating a narrow band chirp signal through the specimens using gel coupled transducers in a transmission mode setup. The received signals were recorded and analyzed using the NLU SPC-I technique. The modified SPC-I technique proposed in this paper can reliably and consistently detect both initiation and progression of damage in the composite plate specimens.
本研究提出了一种用于感测热塑性树脂基复合材料板试件损伤起始和扩展的改进技术。使用称为边带峰值计数指数或 SPC-I 的非线性超声 (NLU) 技术对复合板试件进行研究。本文提出的技术是对以前的 SPC-I 技术的改进。该改进技术提供了更可靠和一致的结果，并可以在较宽的范围内监测损伤的进展。本文介绍了窄带 SPC-I 技术来替代传统的宽带 SPC-I 技术。这里实施的方法在三个方面得到了改进。首先引入了窄带 SPC-I 技术。其次，使用非永久性粘附的凝胶耦合锆钛酸铅 (PZT) 换能器来减少换能器粘附和制造的不一致性。最后，使用更高的采样率设备来提高信号分辨率和峰值计数。该实验是在 4 组使用两种复合材料纤维材料（玻璃和玄武岩）制造的复合材料板试件上进行的，这些材料的损伤程度逐渐增加。使用落锤冲击机以逐渐增加的冲击能量（0 J、10 J、20 J 和 30 J）对复合材料板试件进行损伤。使用凝胶耦合换能器在传输模式设置下通过试件传播窄带啁啾信号来检查复合板试件。使用 NLU SPC-I 技术记录和分析接收到的信号。本文提出的改进 SPC-I 技术可以可靠且一致地检测复合材料板试件中损伤的起始和扩展。
