Phase field simulation of hydrogen-assisted cracking with length-scale insensitive degradation function

Abstract

The present paper applies a length-scale insensitive degradation functionto accelerate the simulation of hydrogen-assisted cracking processes. In this work, the modified Fick's law is used to compute hydrogen flux. The Langmuir - McLean isotherm is employed to calculate the hydrogen surface coverage that deteriorates failure strength and fracture energy of metallic materials. The solid is treated as linear elasticity and the fractures are represented in fixed mesh by phase field variables. In the phase field model, the length-scale insensitive degradation function is employed to separate the phase field length scale from the physical process zone length scale, which enables the simulation of hydrogen-assisted cracking in larger structures with the same mesh density. Numerical examples are provided to demonstrate the applicability of the present method.