Real-time through transmission inspection of aircraft composites using air-coupled ultrasonic arrays

The design, development and initial testing of a fully operational, through transmission ultrasonic array system to perform air-coupled, non-destructive testing (NDT) of advanced composite materials within the aerospace industry is presented. The system offers greater test flexibility and significantly improves the achievable scan rate, when compared with existing water jet systems, without loss of resolution or flaw detection integrity. A focused piezocomposite transducer array system incorporating narrowband, low noise electronics has been designed and developed in order to meet the strict requirements of the aerospace industry. Air-coupled C scans of defective samples, typical of those encountered in the industry, have been obtained using a prototype test system. These are presented and compared with water coupled scans of the same samples.