‘AERONEWS’ – good news for early detection of microdamage
Partners in the EU-funded AERONEWS project met in Ghent, Belgium, on 15 September 2006. The mid-term evaluation of the project is very positive, showing good progress towards improving monitoring of aircraft structural soundness.
Aircraft maintenance requires being able to detect and evaluate early signs of damage in the form of microcracks or delaminations, the weakening of adhesive bonds or thermal and chemical damage. In many cases, early signs of stress-related weaknesses are not easily visible and could very often be missed. Nonlinear Elastic Wave Spectroscopy (NEWS) and related acoustic and ultrasonic methods offer new and innovative possibilities for detecting and imaging incipient damage to aircraft structures.
The next best thing to x-ray vision
NEWS methods offer a new class of non-destructive techniques (NDTs) that provide extreme sensitivity in detecting underlying signs of damage in aircraft and could make a significant contribution to enhancing aircraft and passenger safety, while contributing to substantial cost-savings due to more efficient maintenance techniques.
“For the general public, AERONEWS is a perfect example of how a ‘fundamental’ scientific idea can lead to practical applications,” says project coordinator Koen Van Den Abeele from the Belgium’s Catholic University of Leuven. “The AERONEWS project, running from March 2004 to March 2008, brings together the necessary know-how from universities and research centres, the drive of NDT companies and the experience of aeronautical companies with the aim of realising a better, more reliable and safer inspection system for aircraft structures,” he adds. “It shows that investing in basic research can result in public benefit.”
Safety in motion
The long-term goal of the project (5-10 years) is to develop a system able to monitor, while in operation, the integrity of airframes and aircraft engines, and helicopter rotor systems. Project partners include, research institutes, SMEs and large aeronautics companies from eight Member States. “There is a good interaction between the partners,” notes Van Den Abeele. A hands-on experimental testing week in Prague earlier in the year brought the majority of partners together and helped cement relations. “This has been unique experience, which strengthened the group spirit,” he adds.
So far work has involved experimental investigations of NEWS techniques on a range of simple components (various metals, polymers, welded joints, adhesive bonds and composite laminates) with various kinds of defects (corrosion; fatigue cracks, impact damage and thermal damage). In addition, feasibility tests of several NEWS techniques have been initiated on thin extended structures, complex geometries and rotating parts. Several of these techniques show sensitive ‘signatures’ of defects and are currently being optimised for testing on real aeronautical structures.
A prototype of an integrated NEWS-based inspection system is expected to be ready by Summer 2007 and full-scale tests are scheduled for Winter 2007-2008.