Accounting for non-linear effects in fatigue crack propagation simulations using FRANC3D

Sammanfattning: In this thesis methods to account for non-linear effects in fatigue crack propagation simulations using FRANC3D are evaluated. FRANC3D is a crack growth software that supports automated crack growth in the FE mesh using the power of an external FE code. Introductorily, a theoretical base in fracture mechanics, especially regarding crack propagation models is established. Furthermore, the functionality of FRANC3D is shown for several different applications. As a benchmark for the investigated methods the associated results are compared to data from laboratory tests. The conditions in the test are closely modeled, but with relevant simplifications. The cyclic life-times are calculated using Paris’ law incorporating the stress intensity factors computed by FRANC3D and with material parameters derived from a different set of experiments than those simulated. When comparing the calculated cyclic life-time with the test data it can be seen that the pure linear elastic simulation, for this particular test set-up, gives nearly as good results as the investigated approaches that account for non-linear effects.