Short-Crack Growth Behaviour in Various Aircraft Materials (Le Developpement des Petites Fissures dans Divers Materiaux Aeronautiques)

Abstract : That report describes; the establishment of a common test method, means of data collection/analysis and crack growth modeling in an aircraft alloy AA 2024-T3. The second and concluding phase of this Programme allowed participants to test various materials and loading conditions. The results of this second phase are described in this report. All materials exhibited a short- crack effect to some extent. The effect was much less evident in 4340 steel than in the other materials. For the aluminium, aluminium-lithium and titanium alloys, short cracks grew at stress-intensity factor ranges lower, in some cases much lower, than the thresholds obtained from long crack tests. Several laboratories used the same crack growth model to analyze the growth of short cracks. Reasonable agreement was found between measured and predicted short- crack growth rates and fatigue lives. Keywords: Crack propagation, Mathematical models, Data processing, Fatigue life, Fatigue tests, Aluminum, Aluminum alloys, Titanium alloys, Steels.