Reliable bonds are essential to the integrity of aircraft composite structures throughout their service life. Therefore, NDT methods have been developed to assess bonding quality during maintenance of the aircraft. This application note reviews several methods recently developed for bond testing to improve the reliability of inspection. Olympus, who provides an industry-leading portfolio of innovative test, measurements, and imaging instruments, gives us a little background on nondestructive bond testing for aircraft composites below.
The use of composites in aircraft manufacturing is continuously growing. The main airframe manufacturers like Boeing and Airbus have significantly increased the use of composites in their commercial airliners. While almost the entire body of the Boeing 787 is made of composite, the Airbus A380 and A350 also incorporate significant composite structures. Regional and business jet manufacturers also increased their use of composite. The same growth is being observed in military aircraft such as F22 fighters and A400 transports.
Because aircraft structures are subjected to impacts and lightning strikes, reliable and efficient Nondestructive Testing (NDT) methods are needed to quickly assess damage that may take place. The methods and the necessary instruments have to be easy to understand and use by NDT inspectors all around the world to assure consistency of test results during maintenance checks.
Impacts on aircraft structures can cause different types of damage to composite structures. The damage will vary depending of the nature of the composite part, its composition, and density. On composite laminated structures, a defect created by impact is mainly a delamination between different plies of the fuselage and wing skin. But impact can also cause a disbond between the skin and the stiffeners. Such disbonds can significantly hurt the integrity of the structure. Laminated structures comprise mainly the fuselage of the B787 aircraft as well as the A350.
Olympus explains in detail the necessary instruments they manufcature for the use of discovering damages that may take place with these aircrafts here.