Non-local high cycle fatigue strength criterion for metallic materials with corrosion defects

This paper proposes a volumetric high cycle fatigue (HCF) strength criterion able to quantify the influence of natural corrosion pits on the fatigue limit of a martensitic stainless steel with high mechanical strength. Elastic-plastic numerical simulations were performed for real pits geometry, identified by X-ray microtomography, to determine the local stress distribution. The analysis revealed that calculation of the fatigue strength for material with real (irregular) pit geometry required a non-local HCF strength criterion. Such model was proposed based on the Crossland equivalent stress averaged within a volume limited by a critical distance. This criterion was validated with HCF tests on specimens with natural corrosion defects of different sizes.