Fatigue-life calculations can be remarkably sophisticated, yet their predictions still frequently disagree with experimental results. Is the problem in the material data, the stress analysis, the fatigue model, or in effects that the model simply does not capture?
This question is at the heart of the FABEST Low-Cycle Fatigue (LCF) Competition, a benchmark competition launched by FABER – Fatigue Benchmark Repository COST Action CA23109. FABEST provides participating analysts with a common set of carefully generated experimental input data on a single heat of 42CrMo4 +QT and asks them to predict fatigue behaviour for test cases initially withheld from them. The subsequent comparison with experimental results provides a unique opportunity not only to assess individual prediction methods, but also to quantify the scatter of predictions produced by the fatigue community when solving the same engineering problem from the same starting information.
The experimental campaign and its resulting dataset are therefore an essential foundation of FABEST, but not its final objective. The broader aim is to understand how reliably fatigue life can presently be predicted, which modelling choices contribute most strongly to prediction scatter, and where further methodological development and standardisation are needed.
In this webinar, we;
- Introduce the problem from an engineering perspective, starting with the basic principles of S–N based fatigue-life prediction and gradually addressing the factors that complicate the apparently simple transition from material fatigue data to the life of a real component.
- Look at the different methods that exist to account for mean stress, size and notch effects, surface condition, residual stresses, loading frequency, material orientation, multiaxial loading and other factors that can substantially affect fatigue behaviour, and discuss how much the analyst's choice of method ultimately affects the predicted life.
- Demonstrate, through a simple calculation example, how seemingly moderate differences in the treatment of such effects can propagate into very substantial differences in predicted fatigue life.
Our Speaker
Jan Papuga, PhD, is a fatigue analyst and R&D Visionary at Evektor and a researcher at the Czech Technical University in Prague. His research focuses on fatigue-life prediction, multiaxial fatigue, notch effects and fatigue assessment of engineering structures. He is the developer of the PragTic fatigue-analysis freeware (
www.pragtic.com/program.php), Chair of the Workshop on Computational Fatigue Analysis (
www.pragtic.com/wcfa.php), and Chair of the FABER COST Action CA23109 (
www.faber-cost.eu).
