  The phase field fracture method has emerged as a promising computational tool
for modelling a variety of problems including, since recently, hydrogen
embrittlement and stress corrosion cracking. In this work, we demonstrate the
potential of phase field-based multi-physics models in transforming the
engineering assessment and design of structural components in
hydrogen-containing environments. First, we present a theoretical and numerical
framework coupling deformation, diffusion and fracture, which accounts for
inertia effects.Several constitutive choices are considered for the crack
density function, including choices with and without an elastic phase in the
damage response. The material toughness is defined as a function of the
hydrogen content using an atomistically-informed hydrogen degradation law. The
model is numerically implemented in 2D and 3D using the finite element method.
The resulting computational framework is used to address a number of case
studies of particular engineering interest. These are intended to showcase the
model capabilities in: (i) capturing complex fracture phenomena, such as
dynamic crack branching or void-crack interactions, (ii) simulating
standardised tests for critical components, such as bolts, and (iii) enabling
simulation-based paradigms such as Virtual Testing or Digital Twins by coupling
model predictions with inspection data of large-scale engineering components.
The evolution of defects under in-service conditions can be predicted, up to
the ultimate failure. By reproducing the precise geometry of the defects, as
opposed to re-characterising them as sharp cracks, phase field modelling
enables more realistic and effective structural integrity assessments.
