An overview on fatigue analysis of aeronautical structural details: Open hole, single rivet lap-joint, and lap-joint panel

Over the last years, many efforts have been dedicated to the understanding of fatigue damage of aircraft structures. In order to achieve this goal, attention must be focused on the fatigue phenomena of simpler structural details, conducting research at different scales in terms of specimen size and structural complexity. This paper discusses the fatigue behaviour of different types of specimens with increasing level of geometrical and mechanical complexity. Problems such as the effects of residual stresses due to the cold-working process of rivet holes, load transfer and stress intensity factor calibration of riveted lap-joints, and finally the problem of multiple site damage, are addressed. The residual stress field created by cold expansion was experimentally assessed by using the X-ray technique. Finite element analysis of the different structural details was performed in order to model the residual stresses, stress intensity factor, load transfer and finally fatigue crack propagation. Fatigue tests were supplemented by post-mortem analyses of fracture surfaces in order to measure the location and extent of fatigue damage and the spacing between fatigue striations. The work presented is part of the contribution of IDMEC, Porto to two European Union research projects on the fatigue behaviour of aeronautical structures: ‘SMAAC’ and ‘ADMIRE’.