Luis,
Fatigue Advisor, Creo Simulation’s module for fatigue analysis, is optimized to obtain a rapid indication of whether a design is sensitive to fatigue without having to provide the full range of input normally required to solve this type of problem. The solver technology integrated with Creo Simulation’s Fatigue Advisor is nCode International. The physical nature of fatigue was not widely understood during the early days. August Wöhler therefore took a more pragmatic view of fatigue analysis. The method he developed later became known as nominal stress (or S-N) fatigue analysis. This did not differentiate between the Stage I (crack initiation phase) and Stage II (crack growth phase) growth methods and instead related the nominal stress range to the time taken to complete failure. Though S-N analysis is still widely used in test-based fatigue analysis, it has one major drawback for computer aided engineering (CAE) applications. Fatigue initiation is driven by local plastic strains, but S-N analysis uses elastic stress as the input. Therefore, S-N analysis is unsuitable for performing CAE analysis on components containing local areas of plasticity. For this reason, local strain (or E-N) methods are more universally suitable. Creo Simulation fatigue analysis uses the E-N method, strain (E) vs cycles to failure (N).
