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We describe fatigue processes within the framework of cohesive theories offracture. Crack formation is due to the gradual separation of material surfaces resisted bycohesive tractions. The relationship between traction and opening displacement is governed byan irreversible law with unloading-reloading hysteresis. We assume that the unloadingreloadingresponse of the cohesive model degrades with the number of cycles and assume thereloading stiffness as damage variable. The fatigue behavior is embedded into surface-like finiteelements, compatible with a standard discretization of solid volumes. The potential fatiguecracks are identified by inter-element surfaces, initially coherent. When a fatigue initiationcriterion is satisfied, a self-adaptive remeshing procedure inserts a cohesive element.