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This paper describes an original implementation of a two-parameterscrack growth model for 2D crack propagation simulations under general loadspectrum. In such model, in order to unify the damage process, the following basicparameters are introduced for describing the overall fatigue process: ΔK, Kmax and theinternal stress contribution to Kmax.The coupled usage of Finite Element Method (FEM) and Dual Boundary ElementMethod (DBEM) is proposed in order to take advantage of the main capabilities of thetwo methods. The procedure is validated by comparison with in house obtainedexperimental results and its capability to predict the retardation phenomena followingan overload is assessed. The numerical procedure is tested with reference to an MTaluminium specimen (2024HP-T3), whose fatigue calibration parameters had beenpreviously determined using a CT specimen undergoing a constant amplitude load. As amatter of fact the main advantage of the aforementioned procedure is based on thesimplicity of the crack growth law calibration, in fact, there is no need to calibrate onvarious overload levels but few constant amplitude test are sufficient.One of the main capabilities of the implemented procedure is the possibility to simulateload spectrum effects under linear elastic fracture mechanics, being the plastic effectssimulated by ad hoc body loads, imposed in the BEM analysis (by means of “loadlines”), without the need for any non physical calibration parameters, as in manyphenomenological models aimed at load spectra allowance (Willenborg model, Wheelermodel, etc.). A curvilinear crack path is simulated and reproduced experimentally: thedifferences between the calculated and experimental delay cycles after an overload arecomparable with the typical scatter of such kind of test.