In the rapidly expanding composite industry, novel inspection methods have been developed in recent years. Particularly promising for air-coupled testing are cellular polypropylene transducers which offer better impedance matching to air than piezoelectric transducers. Furthermore, broadband transmitters (laser-induced ultrasound and thermoacoustic emitters) and receivers (optical microphones) have opened a completely new chapter for advanced contact-free ultrasound inspection. X-ray dark-field radiography offers a different approach to detect porosity and microcracks, employing small angle X-ray scattering. These innovative ultrasonic and radiographic alternatives were evaluated in comparison with well-established inspection techniques. We applied thirteen different non-destructive methods to inspect the same specimen (a carbon fiber-reinforced polymer laminate with induced impact damage): air-coupled ultrasound testing (using piezoelectric transducers, broadband optical microphones, cellular polypropylene transducers, and a thermoacoustic emitter), laser-induced ultrasound testing, ultrasonic immersion testing, phased array ultrasonic testing, optically excited lock-in thermography, and X-ray radiography (projectional absorption and dark-field, tomosynthesis, and micro-computed tomography). The inspection methods were qualitatively characterized by comparing the scan results. The conclusions are advantageous for a decision on the optimal method for certain testing constraints.

中文翻译：

---

碳纤维增强聚合物层压板无损检测方法的定性比较

在快速发展的复合材料行业，近年来开发了新的检测方法。空气耦合测试特别有前途的是蜂窝聚丙烯换能器，它比压电换能器提供更好的空气阻抗匹配。此外，宽带发射器（激光诱导超声和热声发射器）和接收器（光学麦克风）为先进的非接触式超声检测开启了全新的篇章。X 射线暗场射线照相提供了一种不同的方法来检测孔隙度和微裂纹，采用小角度 X 射线散射。将这些创新的超声波和射线照相替代方案与完善的检查技术进行了比较。我们应用了 13 种不同的非破坏性方法来检查同一样品（具有诱导冲击损伤的碳纤维增强聚合物层压板）：空气耦合超声测试（使用压电换能器、宽带光学麦克风、蜂窝聚丙烯换能器和热声发射器） 、激光诱导超声检测、超声浸没检测、相控阵超声检测、光激发锁定热成像和 X 射线照相（投影吸收和暗场、断层合成和微计算机断层扫描）。通过比较扫描结果对检查方法进行定性表征。这些结论有利于决定针对某些测试约束的最佳方法。空气耦合超声检测（使用压电换能器、宽带光学麦克风、蜂窝聚丙烯换能器和热声发射器）、激光诱导超声检测、超声浸没检测、相控阵超声检测、光激发锁定热成像和 X 射线射线照相术（投影吸收和暗场、断层合成和微型计算机断层扫描）。通过比较扫描结果对检查方法进行定性表征。这些结论有利于决定针对某些测试约束的最佳方法。空气耦合超声检测（使用压电换能器、宽带光学麦克风、蜂窝聚丙烯换能器和热声发射器）、激光诱导超声检测、超声浸没检测、相控阵超声检测、光激发锁定热成像和 X 射线射线照相术（投影吸收和暗场、断层合成和微型计算机断层扫描）。通过比较扫描结果对检查方法进行定性表征。这些结论有利于决定针对某些测试约束的最佳方法。和 X 射线摄影（投影吸收和暗场、断层合成和微型计算机断层扫描）。通过比较扫描结果对检查方法进行定性表征。这些结论有利于决定针对某些测试约束的最佳方法。和 X 射线摄影（投影吸收和暗场、断层合成和微型计算机断层扫描）。通过比较扫描结果对检查方法进行定性表征。这些结论有利于决定针对某些测试约束的最佳方法。