JEC COMPOSITES MAGAZINE - Issue #52 - October 2009 - 12

EQUIPMENT Control In-field non-destructive bonding verification for aircraft composites Reliable bonds are essential to the integrity of aircraft composite structures throughout their service life. Therefore, non-destructive inspection (NDI) methods have been developed to assess bonding quality during maintenance. This article reviews several methods recently developed to improve the reliability of inspection. depending on the nature of the composite part, its composition, and density. The main defects created by impact on composite laminated structures are delaminations between different plies of the fuselage and wing skin. But impact can also cause disbonds between the skin and the stiffeners. Such disbonds can significantly hurt the integrity of the structures. Laminated structures mainly comprise the fuselage of the B787 and A350. Fig. 2: Damages in a composite sandwich structure. ANDRE LAMARRE, BUSINESS DEVELOPEMENT DIRECTOR AEROSPACE & DEFENSE, OLYMPUS NDT parallel area • Type E: disbonding between inner skin and honeycomb core • Type F: fluid ingress in honeycomb core he use of composites in aircraft manufacturing is growing dramatically. The main airframe manufacturers, such as Boeing and Airbus, have significantly increased the use of composites in their commercial aircraft. While almost the entire fuselage of the Boeing 787 is made of composite, the Airbus A380 and A350 also incorporate significant composite structures. Regional and business jet manufacturers have also increased their use of composite. The same growth is being observed in military aircraft such as F22 fighters and A400 transport aircraft. T Non-destructive inspection methods Bond testing The Olympus BondMaster 1000e+ is a multimode ultrasonic adhesive bond testing instrument that uses pitch-catch modes, mechanical impedance analysis (MIA), and resonance testing to inspect composite materials. This instrument has long been used on most existing aircraft, but new methods have recently been developed. Fig. 1: Delamination in a laminated structure. Because aircraft structures are subjected to impacts and lightning strikes, reliable and efficient NDI methods are needed to quickly assess possible damage. The methods and necessary instruments have to be easy to use by NDI inspectors all around the world to assure the consistency of test results during maintenance checks. Composite sandwich structures are composed of a sandwich of honeycomb core structures (Nomex, etc.) between laminated carbon skins. Different types of damage can be observed in these structures. The following defects can be found after an impact: • Type A: delamination between plies of outer CFRP skin, parallel to surface • Type B: disbonding between the outer skin and the honeycomb core • Type C: cracked honeycomb core parallel to the inspection surface • Type D: crushed honeycomb core in Damage to aircraft composite structures Impacts on aircraft structures can cause different types of damage to composite structures. The damage will vary Fig. 3: Olympus BondMaster 1000e+. jec composites magazine / No52 October 2009

JEC COMPOSITES MAGAZINE - Issue #52 - October 2009

Table of Contents for the Digital Edition of JEC COMPOSITES MAGAZINE - Issue #52 - October 2009