Mechanical modeling of damage accumulation and life evaluation for stress corrosion cracking

摘要

To develop damage evolution models, the process of stress corrosion cracking has been distinguished into two stages of "incubation" and static fatigue. The dominative damage accumulation mechanism in the incubation stage is stress-enhanced corrosion, whereas, in the static fatigue stage, besides the corrosion-enhanced static fatigue mechanism, stress-enhanced corrosion might be nonnegligible too. Life curves with or without threshold behavior can be well explained by considering the contribution of corrosion damage accumulation in the static fatigue stage. It has been found that the incubation life is relatively small if the total life is long, but it will play an important role when total life is short, especially in cases with singular stress field. An equivalent stress has been proposed too to deal with stress corrosion under complicated stress states.