Numerical prediction of railhead rolling contact fatigue crack growth

Artikel i vetenskaplig tidskrift, 2023

The influence of crack face friction on predicted crack growth in a 2D rail model is investigated numerically. An isolated surface-breaking inclined rolling contact fatigue crack is propagated into a rail under (i) a moving contact load, (ii) a combined thermal and contact load, and (iii) a combination of (rail) bending and contact load. Crack face friction is modelled by the Coulomb friction model. The crack growth direction is predicted using an accumulated vector crack tip displacement criterion and two Paris-type equations are employed to estimate crack growth rates. The model is validated towards a twin-disc experiment in the literature. The influence of the crack face friction coefficient and parameters in the crack growth direction criterion are assessed. Frictional cracks tend to go deeper into the rail although the influence under combined thermal and contact loading is minor. In all investigated load scenarios, crack face friction is shown to reduce crack growth rates.