Numerical Modeling of Stress Corrosion Cracking in Steel Structures with Phase Field Method

TL;DR

This paper introduces a new phase field modeling approach that couples mechanical, electrochemical, and chemical effects to predict stress corrosion cracking in steel structures, validated through numerical examples.

Contribution

It develops a novel coupled formulation incorporating electro-chemical effects into the phase field method for SCC prediction, including new energy terms and a modified Allen-Cahn equation.

Findings

Accurately predicts crack propagation due to SCC in numerical tests.

Demonstrates robustness and accuracy of the coupled model.

Provides practical predictions for engineering problems.

Abstract

This study presents a novel coupled mechano-electro-chemical formulation for predicting stress corrosion cracking (SCC) phenomena in steel structures using the phase field method. SCC is a complex damage process that arises from the interaction between mechanical loading and corrosion in a corrosive electrolyte environment. The proposed formulation introduces a new phase-field parameter that aggregates the damage due to mechanical loading and electro-chemical corrosion. To achieve this goal, the internal energies governing the SCC phenomenon are separated into elastic-damage strain energy, the interfacial reaction energy, and energy resulting from changes in corrosion ion concentration. The Allen-Cahn equation is modified to include all energy contributions and calculate the phase field parameter. Furthermore, a specific interfacial kinetic coefficient is introduced to the mechanical energy to take into account corrosion current effects on mechanical properties. The Cahn-Hilliard equation is applied to model the corrosion ion concentration in the domain and the mechanical state of the body is obtained by solving the equilibrium equations. Several numerical examples are presented to validate the robustness and accuracy of the proposed formulation. Finally, the method is applied to predict crack propagation resulting from SCC on two practical engineering problems, yielding promising results.