21st Congress of International Council of the Aeronautical Sciences, Melbourne, Australia, 13-18 September, 1998
Paper ICAS-98-5.3.4

AN IMPROVED FATIGUE APPROACH FOR DESIGNING AIRCRAFT JOINTS

Duprat D., Journet B., Ithurralde C.
Aerospatiale, France

Keywords: fatigue approach, designing aircraft joints

One of the major fatigue problems in airplanes takes place at fasteners holes of junctions. The AIRBUS partner companies mainly resort to efficient technologies such as interference fitting or cold working. The know how in design to take these benefits into account is still very pragmatic. In order to better optimise the design, there is a need to improve the predictive tools and reduce the number of necessary tests. In this respect, this paper proposes simple approaches to predict the fatigue behaviour of cold worked fastener holes for fatigue and damage tolerance design. The rationale is based on the way the residual stresses induced by these technological processes, which 'are the source of benefit, is dealt with. Tests are carried out in order to review the mechanical grounds of the modelling. A retardation coefficient is proposed for the prediction of crack growth. In addition, this paper emphasises a theoretical approach to predict crack initiation and propagation.

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