Corrosion-Fatigue Crack Growth in Plates: A Model Based on the Paris Law

Materials (Basel). 2017 Apr 22;10(4):439. doi: 10.3390/ma10040439.

Abstract

In this paper, a Paris law-based model is presented whereby crack propagation occurs under cyclic loading in air (fatigue) and in an aggressive environment (corrosion-fatigue) for the case of corner cracks (with a wide range of aspect ratios in the matter of the initial cracks) in finite-thickness plates of 316L austenitic stainless steel subjected to tension, bending, or combined (tension + bending) loading. Results show that the cracks tend during their growth towards a preferential propagation path, exhibiting aspect ratios slightly lower than unity only for the case of very shallow cracks, and diminishing as the crack grows (increasing the relative crack depth)-more intensely in the case of bending than in the case of tension (the mixed loading tension/bending representing an intermediate case). In addition, the crack aspect ratios during fatigue propagation evolution are lower in fatigue (in air) than in corrosion-fatigue (in aggressive environment).

Keywords: 316L stainless steel; corner crack; corrosion-fatigue; fatigue crack propagation; finite-thickness cracked plate; numerical modeling; preferential propagation path.