Delamination defects testing and evaluation of composite laminates using phased array ultrasonic technique

Composite materials are prone to delamination defects during the preparation process. For the non-destructive testing and evaluation of carbon fiber reinforced polymer (CFRP) delamination defects, a standard specimen with embedded delamination defects was prepared, and then phased array ultrasonic non-destructive testing technology was used to detect the delamination defects. The qualitative assessment and quantitative evaluation of delamination defects were carried out. First, the delamination defect specimen was prepared with the autoclave forming process, and polyimide films were embedded in the specimen before progress; then, the specimen was inspected using phased array ultrasonic technique, qualitative and quantitative measurement of delamination defects were analyzed with ultrasonic S-scan and C-scan image, uncertainty analysis of test results were also discussed in combination with the sound field simulation. The results show that the shapes of the delamination defects in the sample are regular, the embedment depth and size are consistent with the preset. The index direction size of the delamination defect is more accurate, and the scan direction size is larger than the actual size. Phased array ultrasonic technique can accurately identify the shape, size and position of delamination defects with high detection accuracy and still has good detection effects for small defects.