A thermodynamically-consistent chemo-mechanical-fracture coupled framework for stress corrosion cracking

Abstract

This article aims to provide a simulation tool for effective predictions over the full-life stress corrosion cracking (SCC) behavior of material and structures, for which experimental observation often proves prohibitively time-consuming. To this end, the SCC dynamics is modeled by means of a thermodynamic process. The proposed theory naturally captures the mechanics’ role in SCC development, that is, the high hydrostatic pressure gradient ahead a corrosion pit/crack enhances the moving tendency of the atoms in solid toward the corrosion environments, while the damage caused by such an atom loss in materials favors the crack advancement. The present theory is numerically realized with a phase-field description of the crack profile. To restore the mass transfer behavior near the smeared boundary, an equivalent sink term is adopted in this model. For its engineering predictability, a general strategy for parameter calibration is proposed and validated against experimental results of the crack growth rate (CGR), whose acquisition is far more feasible than that from the long transition period from pit to crack. Two cases bearing clear engineering origin are then studied with the calibrated model, and life-span predictions at a magnitude of years can be made.