Advances in crack growth modelling of 3D aircraft structures

Abstract

This work is focussed on the 3D simulation of crack growth in metal structures which are exposed to complex multiaxial loadings, as regularly occur in aircraft. Simulation of these cracks under the applied loading can be used by the design engineers to investigate changes in the design, loading or materials. Given an initial crack, the aims of the simulation are to identify the stress intensity factors occurring at any stage of the loading cycle, and to predict the time taken for the crack to grow through the structure. This means that vulnerability to fast crack growth is assessed, and that fatigue growth calculations of growth direction and distance are performed and accumulated. The result is that crack life predictions are made of the crack size variation with number of cycles. The use of multi-scale techniques allows sub-models to be created from any part of the model. This enables large-scale FE models to be used for a detailed BE analysis. The paper describes the crack growth in one such sub-model using a variety of initiated crack shapes and positions, and for a range of different loading regimes. © Springer Science+Business Media B.V. 2009.