Fast Non-Contact Composite Inspection For The Aerospace Industry
|The Laser-Ultrasonic inspection System for Aerospace components, called the LUIS, is the product of years of development in efforts to apply laser-ultrasonics to the inspection to polymer-matrix based composite materials, also known CFRP. Laser-ultrasonic is a technique based on non-contact generation and detection of ultrasound with laser light. With laser-ultrasonics, generation and detection of the ultrasound can be made at a distance, without any physical contact with the surface of the component to be inspected. No coupling medium is needed. The ultrasonic probing pulse is always emitted in a direction normal to the surface of the component, regardless of the angle of incidence of the laser beams. There is no need for normal incidence to the surface of the sensor, as is required for conventional pulse-echo ultrasonic inspection systems. Hence, no particular knowledge of the component’s shape is needed prior to the inspection.|
|The LUIS is a complete and functional laser-ultrasonic inspection system, ready to be put into operation for production use. The flexibility of the LUIS allows inspection of both small components, containing acute angle geometry, and large components.|
|The LUIS has the following features:|
|Ease of operation
The LUIS is designed to operate in a production environment. It is a complete “turn key” industrial inspection system. Despite the novelty of the technology, the LUIS is easy to operate due to extensive use of computer and microprocessor controls. No particular knowledge of lasers or laser-ultrasonics is needed to operate the system. The operator can visually supervise at all times the scan in progress thanks to a visible tracer beam superimposed upon the generation and detection laser beams. The scan progress can also be visualized with the aid of a camera mounted directly onto the scanner head. The camera will enable remote monitoring of the scan in progress from the system’s control room.
|Identification of flaw location
The LUIS can detect a wide range of defects within composites and composites bonded with honeycomb structure. With the LUIS, each point of acquisition on the surface of the inspected component is identified by the scanner angular coordinates (qx and qz) and the distance of the target acquisition point to centre of the scanner mirror (measured by a ranging system included). With this information, the position of each acquisition point with respect to the part’s reference point is calculated and used to map the resulting ultrasonic images.
|Non-contact ultrasonic inspection
With the LUIS, laser light is used to generate and detect the ultrasonic probing pulse. Hence, no contact is needed between the inspected component and the inspection system. The component can therefore be inspected in conditions that are not possible with conventional ultrasonic systems (high temperature, vacuum).
The LUIS uses a single scanning mirror to inspect a component. Since the mechanical motions involve in the scanning procedure consists only the tilt and roll of the scanner mirror and since laser-ultrasonic has a relaxed normalcy requirements, complex-shaped composite components can be inspected with a speed and flexibility not available with conventional pulse-echo ultrasonic inspection systems.
|Independence to shape of components
The LUIS can inspect components of a variety of shapes. The only requirement is an optical line of sight between the area to be inspected on the component and the generation unit scanner.
|With the LUIS, the advantages of laser-ultrasonic inspection are now available for industrial applications to composite components of complex-shapes.|