del Busto, SusanaSusanadel BustoBetegon, CovadongaCovadongaBetegonMartinez-Paneda, EmilioEmilioMartinez-Paneda2019-09-192019-09-192017-11-01Engineering Fracture Mechanics, 2017, 185, pp.210-2260013-7944http://hdl.handle.net/10044/1/73443We present a compelling finite element framework to model hydrogen assisted fatigue by means of a hydrogen- and cycle-dependent cohesive zone formulation. The model builds upon: (i) appropriate environmental boundary conditions, (ii) a coupled mechanical and hydrogen diffusion response, driven by chemical potential gradients, (iii) a mechanical behavior characterized by finite deformation J2 plasticity, (iv) a phenomenological trapping model, (v) an irreversible cohesive zone formulation for fatigue, grounded on continuum damage mechanics, and (vi) a traction-separation law dependent on hydrogen coverage calculated from first principles. The computations show that the present scheme appropriately captures the main experimental trends; namely, the sensitivity of fatigue crack growth rates to the loading frequency and the environment. The role of yield strength, work hardening, and constraint conditions in enhancing crack growth rates as a function of the frequency is thoroughly investigated. The results reveal the need to incorporate additional sources of stress elevation, such as gradient-enhanced dislocation hardening, to attain a quantitative agreement with the experiments.© 2017 Elsevier Ltd. All rights reserved. This manuscript is licensed under the Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International Licence http://creativecommons.org/licenses/by-nc-nd/4.0/.Science & TechnologyTechnologyMechanicsHydrogen embrittlementCohesive zone modelsHydrogen diffusionFinite element analysisFatigue crack growthSTRAIN GRADIENT PLASTICITYCRACK-PROPAGATIONHYDROGEN DIFFUSIONFINITE-ELEMENTSTRENGTHFRACTUREGROWTHNUCLEATIONTRANSPORTJournal Articlehttps://www.dx.doi.org/10.1016/j.engfracmech.2017.05.0211873-7315