MODELING OF HYDROGEN EMBRITLLEMENT USING MIXED NONLOCAL FINITE ELEMENTS
Daniella Lopes PintoGrand Ballroom C
Industrial power generation and transmission structures are designed to have a service life of 40 years. Knowledge of the evolution of material behavior over long periods of time is therefore crucial to ensure the safety and reliability of these facilities. Due to the continuously increasing power demand, new energy sources are needed. As part of the decarbonization of these sources, hydrogen will play an important role as an energy vector. However, hydrogen can easily diffuse in materials, inducing premature failure with reduced ductility and toughness. This phenomenon, called hydrogen embrittlement (HE), is a complex mechanism which combines mechanical and chemical loadings. Therefore, this work presents a strategy to simulate HE by the finite element method integrating plasticity and damage coupled to hydrogen diffusion. Since damage is highly dependent on local stresses and hydrostatic pressure mixed formulations in displacement, pressure and volume variation have been proposed to control volumetric locking. To represent ductile rupture, the Gurson-Tvergaard-Needleman (GTN) model based on an implicit gradient nonlocal formulation with two internal lengths is considered, which allows regularizing void growth and strain-controlled nucleation. All the implementations and simulations have been carried out using the Z-set software.