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Session: Airworthiness considerations
Session starts: Wednesday 28 June, 10:50
Presentation starts: 10:50

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Rik-Jan Lemmen (Airbus Operations GmbH)
Derk Daverschot (Airbus Operations GmbH)
Paul Mattheij (Airbus Operations GmbH)
Thomas Beumler (Airbus Operations GmbH)

Abstract:
This paper presents the approach for the FAR26.21 Widespread Fatigue Damage (WFD) compliance demonstration for GLARE® skin panels of the A380-800. In 1997, Airbus decided to apply this Fibre Metal Laminate (FML) as a novel structural material for the fuselage skin panels of the A380-800. GLARE® is developed with the vision to combine the high-strength properties of glass fibres with the advantages offered by metals, i.e. stability, ductility, isotropy, etc. As a result, a structural material is developed, which exhibits excellent damage tolerance and residual strength capabilities. A holistic development approach ensures that all requirements for certification, manufacturing and operation are considered from the start. Consequently, the FAR26.21 WFD requirement is anticipated at type certification. Moreover, the full-scale fatigue test was exploited to fully support the F&DT and WFD certification by ensuring significant coverage. Following completion of the full-scale fatigue test, a tear-down campaign is performed, which provided information on the health of the structure at the end of the test. The tear-down included an extensive inspection campaign of the tested structure with dismantling and detailed inspection of all areas relevant for F&DT and WFD compliance. In addition to the inspections on the tested structure, test coupons are extracted from areas representing specific design solutions, which exhibited most fatigue damage in order to conduct residual strength tests. The test results confirmed that the residual strength capability exceeds limit loads and exhibits even significant margin beyond ultimate load. For the WFD compliance exercise, the list of WFD candidates from the FAA are evaluated as a minimum. Additionally, GLARE® design specific areas such as the Splices®, the internal doubler run-outs are evaluated. It became apparent during the A380-800 WFD compliance exercise that the holistic development approach of GLARE® resulted in a structural material concept with outstanding damage tolerance properties; i.e. no crack-tip interaction, ultimate load capability, etc. These properties, together with the design principles and margins applied at design, significantly simplified the WFD compliance exercise for the A380-800 GLARE® structure.