The aim of a fatigue analysis on industrial welded structures submitted to complex loadings is to evaluate the lifetime to initiate a crack and to propagate it, until the failure of the structure occurs. In this study, we present a multi-scale approach, based on the use of finite elements from the global cartography of the damaged zones to the local calculation with cracks inserted in the models. Crack propagation is performed using multi-initiation of cracks at weld toes, Line Spring elements to take into account the flexibility due to cracks and Crack Box Technique allowing to precisely calculate the stress intensity factors. CBT is also used to determine the crack path and to calculate crack closure under variable loads. All these developments have been included in the software VERICRACK to assess crack initiation until failure. This approach has been applied to an overall aluminium welded structure in which, results are in good agreement with calculations.
