Novel Characterizations of Effective SIFs and Fatigue Crack Propagation Rate of Welded Rail Steel Using DIC

The fatigue crack growth-rate test of rail head, waist, and bottom material for U71Mn welded was carried out. Digital image correlation (DIC) used to capture the full-field displacement. crack-tip position accurately obtained based on displacement data, an accurate opening (CTOD) measurement point found. CTOD values head under overloaded unloaded condition were extracted, area size elastic plastic obtained. According COD data different experimental conditions, corresponding force function introduced Elber model, a calculation method effective stress-intensity factors (SIFs) considering plasticity-induced closure proposed. results in this paper provide some references assessing life rail.