A Fully Coupled Mechano-Chemical Digital Model for Environment-Induced Damage and Damage Propagation

It is vital to enable and establish both comprehension and simulation of environment-induced damage processes for predicting the remaining ser-vice life of engineering structures and components, conducting reliability analysis, and designing to enhance the material’s overall resistance to such damage. A fully coupled mechano-chemical peridynamic (PD) model for environment-induced degradation, including corrosion, was developed based on both peridynamic corrosion theory and the mechano-chemical effect theory. When the conditions for phase transition are satisfied, the movement of boundaries occurs autonomously, without requiring any supplementary boundary conditions to be specified within the model. This model effectively simulates degradation arising from the combined and interactive influences of mechano-chemical phenomena. To validate the model, in-situ electrochemical tests and stress corrosion cracking tests were conducted, with the results used to explore the effects of stress and/or load on the kinetics of environment-induced damage in an aluminum alloy. The experimental electrochemical parameter values closely match theoretical predictions, validating the mechano-chemical effects. As stress levels increase, the corrosion potential of aluminum alloy 7050 shifts neg-atively, corrosion current density increases, and the severity of corrosion worsens. The explicit finite difference method was employed to simulate the damage evolution of a typical stress corrosion crack in the aluminum alloy. This numerical model easily simulates the morphological evolution of corrosion pits with arbitrary shapes under different stress conditions during growth. The numerical predictions closely match the experimental findings. This innovative study demonstrates that the fully coupled mechano-chemical peridynamic corrosion model can accurately capture environment-induced damage and is a valuable tool for investigating the propagation and growth of such damage in aggressive environments.