In the field of aerospace materials and structures, water coupled ultrasonic testing was not desirable due to changes in properties and contamination reason. Therefore, in the present study non-contact air coupled ultrasonic transducers were proposed as an alternative examination for such applications. This present study describes our practical knowledge of using piezoelectric air-coupled transducers for visualization and defect identification of aluminium, CFRP and epoxy-resin specimens. Further, the effectiveness of the system is verified by experiments conducted in the inspection of artificial defects and 2D images was reconstructed through scanning of specific specimen surface. Results show that, all the created defects were identified successfully using C-scan technique. The measured defect values were compared with experimental defect values and shows good agreement. The 1 MHz piezoelectric transducer was the best for all the three specimens which is used in the present study because of the material structure being evaluated. The bulk wave piezoelectric transducer was identified as extensive pulse attenuation by the structure of the aluminium, CFRP and epoxy resin.

在航空航天材料和结构领域，由于性能变化和污染原因，水耦合超声测试是不可取的。因此，在本研究中，提出了非接触式空气耦合超声换能器作为此类应用的替代检查。本研究描述了我们使用压电空气耦合换能器对铝，CFRP和环氧树脂样品进行可视化和缺陷识别的实践知识。此外，该系统的有效性通过在人工缺陷检查中进行的实验得以验证，并且通过扫描特定样本表面重建了2D图像。结果表明，使用C扫描技术可以成功地识别出所有产生的缺陷。将测得的缺陷值与实验缺陷值进行比较，并显示出良好的一致性。由于要评估的材料结构，在本研究中使用的所有三个样品中，最佳的1 MHz压电换能器。铝，CFRP和环氧树脂的结构将体波压电换能器识别为广泛的脉冲衰减。