Air-coupled transducer tilted C-scan for delamination introduced during the manufacturing process in CFRP plates

Carbon fibre reinforced polymers (CFRPs) have gained attention as viable substitutes for conventional metals and alloys in weight-sensitive applications like aerospace, primarily because of their outstanding strength-to-weight characteristics. Nevertheless, these materials are susceptible to intricate and challenging-to-anticipate sub-surface impairments, such as delamination after certain impacts. Non-destructive ultrasonic testing (NDT) is a widely employed technique for examining workpieces’ properties. Nonetheless, conventional ultrasonic testing faces significant constraints due to the necessity of physically coupling ultrasonic transducers to the test medium, typically involving substances like liquid and gel, which could cause unnecessary corrosion and pollution on composite materials. This study proposed a tilted non-contact C-scan detection on carbon composite plates with internal delamination based on air-coupled transducers (ACT). By introducing a tilted C-scan method, the subtle pre-fabricated internal impurities can be detected.