Examinando por Autor "Neto, Diogo Mariano"
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Ítem Effect of crack flank holes on fatigue crack growth(Elsevier, 2023-01-07) Neto, Diogo Mariano; Cavaleiro, Nuno; Sérgio, Edmundo; Jesus, Joel de; Camacho-Reyes, Alonso; Antunes, Fernando VenturaThe effect of drilling two symmetric holes along the crack flanks on the fatigue crack growth (FCG) rate was evaluated numerically. The FCG increases (decreases) when the crack tip is behind (ahead) the holes. This behaviour is enlarged both by increasing the diameter of the holes and by reducing the distance between them. This is consequence of the geometrical effect, which modifies the plastic zone size. Experimental work validated the numerical model, indicating that that cumulative plastic strain at the crack tip is an adequate crack driving force and that cyclic plastic deformation is the main damage mechanism of FCG.Ítem Experimental analysis of the plastic CTOD to characterize the variable amplitude fatigue crack growth in Grade 2 titanium samples(Elsevier, 2023-05-23) Gómez-Gonzales, Giancarlo Luis; Vasco, José Manuel; Antunes, Fernando Ventura; Neto, Diogo Mariano; Diaz-Garrido, Francisco AlbertoIn this paper, the plastic component of the crack-tip opening displacement (CTODp) is experimentally evaluated to characterize the fatigue crack growth behavior in a Grade 2 titanium sample under single overload with constant amplitude loading conditions. The CTOD measurements were performed with the 2D-Digital Image Correlation (DIC) technique. The experimental results show a linear correlation between CTODp and fatigue crack growth rates, suggesting the independence of this relationship to load-interaction effects. Therefore, this study demonstrates that the CTODp can be a suitable crack-driving parameter to study crack propagation behavior under variable amplitude loading. Furthermore, it suggests that the fatigue crack growth process is primarily caused by cyclic plastic deformation.Ítem Numerical analysis of compliance and fatigue life of the CCC specimen(Elservier, 2023-01-23) Neto, Diogo Mariano; Antunes, Fernando Ventura; Sérgio, Edmundo; Branco, Ricardo; Camacho-Reyes, Alonso; Díaz-Garrido, Francisco Alberto; Gómez-Gonzales, Giancarlo Luis; Vasco, José ManuelThis study presents the numerical evaluation of the compliance in the CCC specimen aiming to assess the crack length inside the specimen. The numerical model considered the elastoplastic behaviour of the specimen, which is modelled using axisymmetric finite elements. The results shown that the propagation of the crack yields a nonlinear increase of the compliance. Nevertheless, variation of the compliance is very small for small values of crack radius. Considering a loading sequence composed by four load blocks of constant amplitude, the fatigue crack growth was predicted both using the Paris law and the numerical model. Both predictions agree but only the numerical simulation is able to capture the crack retardation between load blocks