A novel optical air-coupled ultrasound NDE sensing technique compared with infrared thermographic NDT on impacted composite materials

摘要

In this paper, a novel optical air-coupled ultrasound (O-ACU) sensing technique is proposed. A wide broadband (5 Hz - 1 MHz) laser-acoustic based optical microphone worked as probe in an air-coupled ultrasound (ACU) system. The O-ACU modality was used to inspect several CFRP and GFRP impacted laminates and the results were compared with the classical ACU modality. Infrared thermography. as an established reference technique, was used for validation. Advanced image processing techniques were applied. Conclusively, O-ACU shows an obvious improvement in sensitivity and resolution.