A model to assess the fatigue behaviour of ageing aircraft fuselage

A computer efficient model for assessing the fatigue behaviour of ageing aircraft components in the presence of multiple site damage is introduced. The model involves the computation of crack initiation scenarios on the basis of a probabilistic approach and the estimation of the fatigue behaviour of complex, highly loaded aircraft structures using a deterministic concept. To reduce the computing effort because of the model size and mesh difficulties in crack propagation calculations, a sub-structuring procedure under the FE method is utilized. An incremental approach for calculating crack initiation and crack propagation has been involved; it leads to a further essential reduction of the computing effort. Computer simulation is compared with experimental results for characteristic multiple site damage problems of aluminium 2024 lap and butt joints.