Cohesive zone modelling of hydrogen assisted fatigue crack growth: The role of trapping

Integrated Computational Materials Engineering for Advanced Automotive Technology: With Focus on Life Cycle of Automotive Body Structure

“…Moreover, they extended their work by integrating the cohesive zone model and presented a processing map to identify the relationship between the loading frequency, carbide trap densities, and fatigue crack growth. [222] The results showed that the ratio of the effective hydrogen diffusivity to the loading frequency controlled the fatigue crack growth behavior. Golahmar et al proposed a coupled deformation-diffusion-damage model using the PF theory to predict hydrogen-assisted fatigue cracks with crack initiation and propagation for arbitrary loading patterns and specimen geometries.…”

“…Moreover, they extended their work by integrating the cohesive zone model and presented a processing map to identify the relationship between the loading frequency, carbide trap densities, and fatigue crack growth. [ 222 ] The results showed that the ratio of the effective hydrogen diffusivity to the loading frequency controlled the fatigue crack growth behavior. Golahmar et al.…”

Hydrogen Embrittlement as a Conspicuous Material Challenge─Comprehensive Review and Future Directions

“…795 Subsequent models have integrated stress and plasticity effects on H distribution and their influence on elasto-plastic deformation. 220,796 Cohesive zone models were coupled with H diffusion analysis 797 and trapping kinetics, 798 capable of simulating the frequency dependence of H-related FCG rate. As the relationship between H and plasticity becomes more intricate, dislocation-based plasticity models, particularly those using a crystal plasticity approach coupled with H kinetics, are being explored.…”

“…From a predictive modeling perspective, early fracture mechanics-based models for cycle-dependent H-accelerated FCG focused on factors like H concentration and penetration distance from the crack tip, along with yield strength, but mechanisms of H–dislocation interaction, hydrostatic stress-driven H diffusion, and H trapping, were not sufficiently incorporated . Subsequent models have integrated stress and plasticity effects on H distribution and their influence on elasto-plastic deformation. , Cohesive zone models were coupled with H diffusion analysis and trapping kinetics, capable of simulating the frequency dependence of H-related FCG rate. As the relationship between H and plasticity becomes more intricate, dislocation-based plasticity models, particularly those using a crystal plasticity approach coupled with H kinetics, are being explored. , These models account for vacancy generation and dislocation-mediated H transport, moving toward a more comprehensive simulation of H-accelerated FCG.…”

Critical hydrogen concentration for crack propagation in a CrMo steel: Targeted experiments for accurate numerical modelling

“…The analysis of the fracture surface after a fracture toughness test can identify the mechanism or mechanisms and support the choice of the most suitable numerical framework. Besides this focus on the active mechanism, the numerical literature based on the Finite Element Method (FEM) reports some strategies to simulate crack advancement and fracture energy degradation in presence of hydrogen, such as the phase field modelling [22,23], the peridynamics [24,25] and the Cohesive Zone Modelling (CZM) [19,26]. This last numerical strategy is suitable when crack propagation is known, as in the case of laboratory toughness tests on standard C(T) specimens.…”