A phase field model for hydrogen-assisted fatigue

TL;DR

This paper introduces a phase field model that predicts hydrogen-assisted fatigue crack initiation and growth, capturing complex loading effects and matching experimental results.

Contribution

The work develops a coupled deformation-diffusion-damage phase field model for hydrogen-assisted fatigue, enabling comprehensive predictions of crack behavior under various conditions.

Findings

Hydrogen increases fatigue crack growth rates.

The model reproduces Paris law behavior across different hydrogen levels.

Virtual S-N curves align well with experimental data.

Abstract

We present a new theoretical and numerical phase field-based formulation for predicting hydrogen-assisted fatigue. The coupled deformation-diffusion-damage model presented enables predicting fatigue crack nucleation and growth for arbitrary loading patterns and specimen geometries. The role of hydrogen in increasing fatigue crack growth rates and decreasing the number of cycles to failure is investigated. Our numerical experiments enable mapping the three loading frequency regimes and naturally recover Paris law behaviour for various hydrogen concentrations. In addition, Virtual S-N curves are obtained for both notched and smooth samples, exhibiting a good agreement with experiments.