In this work, the Affected Depth (AD) approach is employed to estimate the high cycle fatigue limit of AISI 416 steel weakened by notches. This approach is based on a critical depth parameter identified from the analysis of the stress distribution around the defect. Elasto-plastic finite element calculations have been performed to determine the stress field close to the notch. Where the notch is modeled by a discontinuity of matter (void) characterised by: (i) a notch depth and (ii) a notch tip radius. The Crossland equivalent stress is employed to compute the stress surrounding the notch of a V-notched material submitted to fully reversed torsion and tension loadings. The experimental results of notched materials, used for model validation, are obtained from the literature. In the first part of the paper, Fatigue Limit diagram is simulated by assessing the fatigue limits to validate the AD model for notched components. The prediction of the fatigue strength is consistent with the experimental investigation taken from the literature, and it provides interesting results. In the second part of the paper, two points are treated: (i) The effect of the notch acuity on the plastic strain and the stress concentration. It allows testing the capability of the AD approach to describe the fatigue behavior of the V-notched components. (ii) The impact of the notch tip radius on the affected depth parameter of notched low carbon steel.
Dans ce travail, l’approche de la profondeur affectée (AD) est employée pour estimer la limite de fatigue à haut cycle de l’acier AISI 416 affaibli par des entailles. Cette approche est basée sur un paramètre de profondeur critique identifié à partir de l’analyse de la distribution des contraintes autour du défaut. Des calculs élasto-plastiques par éléments finis ont été effectués pour déterminer le champ de contraintes à proximité de l’entaille. L’entaille est modélisée par une discontinuité de matière (vide) caractérisée par : (i) une profondeur d’entaille et (ii) un rayon de la pointe de l’entaille. La contrainte équivalente de Crossland est utilisée pour calculer la contrainte entourant l’entaille d’un matériau entaillé en V soumis à des charges de torsion et de tension totalement inversées. Les résultats expérimentaux des matériaux entaillés, utilisés pour la validation du modèle, sont tirés de la littérature. Dans la première partie de l’article, le diagramme de limite de fatigue est simulé en évaluant les limites de fatigue afin de valider le modèle AD pour les composants entaillés. La prédiction de la résistance à la fatigue est cohérente avec l’étude expérimentale tirée de la littérature et fournit des résultats intéressants. Dans la deuxième partie de l’article, deux points sont traités : (i) l’effet de l’acuité de l’entaille sur la déformation plastique et la concentration de contrainte. Cela permet de tester la capacité de l’approche AD à décrire le comportement en fatigue des composants entaillés en V. (ii) L’impact de l’acuité de l’entaille sur la déformation plastique et la concentration de contrainte. (ii) L’impact du rayon de la pointe de l’entaille sur le paramètre de profondeur affectée de l’acier à faible teneur en carbone entaillé.
Revised:
Accepted:
Published online:
Mot clés : Fatigue à grand nombre de cycle, Profondeur affectée, Diagramme de limite de fatigue, Entaille en V, Rayon de l’extrémité de l’entaille
Marwa Youssef 1; Anouar Nasr 1, 2
@article{CRMECA_2024__352_G1_223_0, author = {Marwa Youssef and Anouar Nasr}, title = {Study of {V-notch} fatigue strength based on affected depth approach}, journal = {Comptes Rendus. M\'ecanique}, pages = {223--237}, publisher = {Acad\'emie des sciences, Paris}, volume = {352}, year = {2024}, doi = {10.5802/crmeca.264}, language = {en}, }
Marwa Youssef; Anouar Nasr. Study of V-notch fatigue strength based on affected depth approach. Comptes Rendus. Mécanique, Volume 352 (2024), pp. 223-237. doi : 10.5802/crmeca.264. https://comptes-rendus.academie-sciences.fr/mecanique/articles/10.5802/crmeca.264/
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