Robotized Laser-Ultrasonic NDT system for large aircraft structures

Speaker:
Huber, Norbert; RECENDT; Austria

Authors:
Huber, N.; RECENDT - Research Center for Non-Destructive Testing GmbH; Austria
Gärtner, M.; RECENDT - Research Center for Non-Destructive Testing GmbH; Austria
Reitinger, B.; RECENDT - Research Center for Non-Destructive Testing GmbH; Austria
Hofer, C.; RECENDT - Research Center for Non-Destructive Testing GmbH; Austria
Scherleitner, E.; RECENDT - Research Center for Non-Destructive Testing GmbH; Austria
Burgholzer, P.; RECENDT - Research Center for Non-Destructive Testing GmbH; Austria
Graf, N.; InnoLas Laser GmbH; Germany
Nicholson, P.I.; TWI Technology Centre (Wales); United Kingdom
Lindop, M.; TWI Technology Centre; United Kingdom
Burns, D.; KUKA Systems UK Ltd; United Kingdom
Incarnato, C.; Leonardo S.p.A.; Italy

ID: ECNDT-0276-2018
Download: PDF
Session: Laser UT 2
Room: J1
Date: 2018-06-14
Time: 11:30 - 11:50

In this presentation, we will show the actual development stage of a new technical approach for a laser based NDT system for fast and contactless testing of large carbon fiber reinforced polymer (CFRP) aircraft structures. The approach is based on a non-contact laser ultrasound technique with delivery of both the laser ultrasound excitation and detection pulses through flexible optical fibers. The backscattered light is also collected into a fiber. The measurement head, which contains the twobeam outputs and the light collection optics is scanned over the surface by a 6-axis lightweight robot arm. The excitation and detection lasers are based on diode pumped Nd:YAG lasers which enable a low profile casing with low weight and very long lifetime with little maintenance and high scanning speed of around 500Hz. Both lasers are based on commercial laser designs by Innolas and are specially redesigned for the required specifications. For the demodulation of the ultrasonic waves, both a balanced two wave mixing interferometer (B-TWM) and a dual confocal Fabry-Perot Interferometer (D-CFPI) are tested. In the presentation, the results of their suitability to different defect types and CFRP layer structures will be shown.
The overall goal of the shown developed system is to obtain the optimum technology for the non-destructive inspection of both present and future generation hybrid aircraft and thick composite structures, containing acoustic damping materials, which highly attenuate ultrasonic waves. In the follow-up of this Clean Sky 2 project “ACCURATe”, the prototype system will be validated via deployment to inspect a long barrel demonstrator, which is to be developed in the Clean Sky 2 program using hybrid materials technology.

Acknowledgment: The Project (“ACCURATe”) leading to these results has received funding from the Clean Sky 2 Joint Undertaking under the European Union’s Horizon 2020 research and innovation program under Grant Agreement n°755616.