Evaluations and enhancements of fatigue crack initiation criteria for steels subjected to large shear deformations
Journal article, 2024

While large accumulated plastic deformations occur in the rail surface layer where rolling contact fatigue cracks initiate, many available Low Cycle Fatigue (LCF) crack initiation criteria focus on small plastic strains. Accordingly, this paper evaluates available fatigue crack initiation criteria for highly shear-deformed R260 steels, reflecting the conditions in the surface layer of rails. Furthermore, modified crack initiation criteria are suggested. The evaluation is based on three different experiments: Large shear strain increments under varying axial loading (predeformation), strain-controlled LCF tests after some predeformation, and axial High Cycle Fatigue (HCF) experiments. For the predeformation, Finite Element (FE) simulations, with a large-strain plasticity model for cyclic and distortional hardening, provide predictions of the local stress and strain histories. A cross-validation procedure is used to assess the accuracy and reliability of both established and modified fatigue crack initiation criteria. The proposed modifications to one of the criteria show an improved fit to the experimental data. However, there is a tendency to overfitting, which can be improved by including more experimental data.

Anisotropy

Finite element simulations

Crack initiation criteria

Tension–torsion tests

Large deformations

Author

Nasrin Talebi

Chalmers, Industrial and Materials Science, Material and Computational Mechanics

Johan Ahlström

Chalmers, Industrial and Materials Science, Engineering Materials

Magnus Ekh

Chalmers, Industrial and Materials Science, Material and Computational Mechanics

Knut Andreas Meyer

Technische Universität Braunschweig

International Journal of Fatigue

0142-1123 (ISSN)

Vol. 182 108227

Driving research and innovation to push Europe's rail system forward (IN2TRACK3)

Swedish Transport Administration (2021/19114), 2021-01-01 -- 2023-12-31.

European Commission (EC) (EC/H2020/101012456), 2021-01-01 -- 2023-12-31.

IAM4RAIL

Swedish Transport Administration (2023/9635), 2023-01-01 -- 2026-02-28.

Subject Categories

Applied Mechanics

Metallurgy and Metallic Materials

DOI

10.1016/j.ijfatigue.2024.108227

More information

Latest update

3/11/2024