Fracture mechanics and hot spot stress‐based fatigue life calculation: Case study for a crane runway girder

Abstract This work presents the case study of a welded overhead crane runway girder. A full‐shell global finite element model was developed and validated using strain measurements. The global model drives solid submodels of different scales. Using load spectra based on real operational data, hot spot stress and XFEM‐based fracture mechanics simulations are performed to assess the fatigue properties of two critical joints. For the fracture mechanics‐based approach, it is shown that small cracks quickly converge to the same aspect ratio. Hence, the choice of the initial crack aspect ratio was found to be inconsequential. But the aspect ratio must not be assumed to be constant during the fatigue crack growth simulations. Finally, it is shown that the size at which a crack is transferred from one submodel to a subsequent is critical for the accuracy of the fatigue crack growth simulations.