NDT with laser ultrasonic of complex composites

During the past years the quantity and complexity of composite materials used in aircraft and automotive manufacturing has increased continually. Composite CFRP (Carbon Fibre-Reinforced Plastic) parts consist of carbon fibres which are embedded in an epoxy matrix. This leads to excellent mechanical properties with high strength and stiffness at low weight. Complex compositions need complex testing procedures especially in the investigation of small radii of curvatures. We report on a laser ultrasonic system using a CO2-laser as the generation laser and a Nd:YAG long pulse laser as the detection source. The backscattered and frequency shifted laser light will be analyzed by a confocal Fabry-Perot interferometer. It will be shown that flaws and material defects at complex aircraft composites like cracks, disbonds or delamination can be detected. The range of inspected components goes from flat composites over lightly shaped to complex formed geometries. Porosity in composites parts have been verified also