AERONAUTICS - AEROSPACE
Always at the cutting edge of NDT
Between the increase in air traffic and the service life of aircraft, their reduced weight (new materials) and the upsurge in ecological sensitivity, the French aeronautical and space industry has played a leading role in numerous programmes, both in Europe and worldwide. The ever-growing use of non-destructive testing is one key to this success.
During manufacture, the different composite components of the fuselage, half-wings, wings and engines are tested to verify and control the appearance of defects during operation. A variety of tests are conducted before any assembly takes place, from penetrant testing to magnetic particle testing via radiography and ultrasounds. As composites, complex alloys and even ceramics are the materials used most frequently in this sector, this makes the tests more tedious to perform.
The majority of planes are still operated after over thirty years in service. To ensure the in-flight safety of passengers and flight crew, NDT is used for early prediction of the resistance of components to the different types of damage that may occur - the two most common are fatigue and corrosion.
Some frequent tests take place directly on the tarmac whereas others require dismantling and even a return to the factory. ‘Conventional’ methods are generally applied to mechanical parts in engines, landing gear, control linkage, etc.
Radiography testing is more common for attachment areas for wings, motors and certain fuselage components. Digital imaging can be used to reduce the radiation doses and thus increase the area accessible to the personnel.
Eddy current testing is used in riveted areas, mainly to detect cracking or corrosion in metal or sandwich panels. Acoustic emission testing can also be set up to detect corroded areas.
The range of tests is rounded out by shearography and laser interferometry, both of which are widely used when mechanical or thermal stress is applied.