Corrosion-fatigue life prediction for notched components based on the local strain and linear elastic fracture mechanics concepts

摘要

An initiation-propagation model based on the local strain and linear elastic fracture mechanics concepts has been investigated for application to predict the fatigue life of notched components exposed to a corrosive environment. Estimates of the corrosion-fatigue crack initiation lives were obtained using strain-life relationships. The Paris power law was used to obtain the estimates of corrosion-fatigue crack propagation lives. Estimated corrosion-fatigue lives were compared with the experimentally obtained corrosion-fatigue life data using centre-notched specimens of three types of modified Al-2.5Mg alloy exposed to an Arabian Gulf seawater environment. Good fatigue life estimates were obtained both in air and in Arabian Gulf seawater environments for all three types of alloy. It is shown that good corrosion-fatigue life predictions can be made by determining the relevant fatigue parameters via a few simple constant-amplitude fatigue tests on smooth specimens and a few crack growth rate tests in the environment at the frequency of interest.