Visualization of Lamb Wave Propagation in Uncured CFRP and Curved Surfaces Using Air-Coupled Ultrasound.

Propagation of Lamb waves, generated and detected using air-coupled piezoelectric transducers (0.1-1.0 MHz), is visualized. Hence phase and group velocities are obtained. The technique is first tested on plates (aluminum and carbon fiber reinforced polymers -CFRP- plates). Then it has been applied to un-cured CFRPs plates and curved surfaces: steel pipes and vessels and to the curved section of CFRP beams. Two different experimental set-ups are proposed: 1) use of monolithic transducers and mechanical scans along the direction of propagation, 2) use of a phased array linear transducer and an electronic scan along the direction of propagation.