Delamination detection in holed CFRP laminates using visualized ultrasound propagation

This study applied a newly developed technique for visualizing ultrasonic waves to damage detection in holed CFRP laminates. This technique provided a moving diagram of propagating waves with the use of a pulsed laser for generation scanning a specimen and a fixed transducer for reception. Multiple types of damage (i.e. splits, transverse cracks and delamination), as well as delamination during processing, were observed near the hole in the loaded specimens by soft X-ray radiography. The specimens were then inspected by visualizing the propagation of ultrasonic waves. The S₀ and A ₀ Lamb modes were visualized on the CFRP cross-ply laminate. Furthermore, we successfully detected delamination near the hole through the appearance of scattered waves. These inspection results agreed well with that by soft X-ray radiography, and consequently confirmed the usefulness of the technique for visualizing ultrasonic waves in inspection for composite laminates.