Fatigue Design of Notched Components with Stress Gradients and Cyclic Plasticity

Abstract

Conference: 27th Spring Meeting on Fatigue and Plasticity Paris, FRANCE, 2008International audienceThis paper shows that fatigue strength of notched specimens under cyclic loading can be simply and accurately estimated by using elastic-plastic computations and averaging stress over a critical volume obtained by an optimisation process minimizing the dispersion between experiments and simulations. The Dang Van high cycle fatigue criterion is considered. Fatigue tests (tension-compression, bending and torsion) carried out by the Cetim, are used to calibrate the critical volume

Modélisation numérique du phénomène defretting-fatigue intervenant dans le vieillissement des conducteurs de lignes aériennes

“…Par la même source, la contrainte limite ultime R m est évaluée à 180 MPa. En appliquant une approche empirique [23], basée notamment sur l'utilisation de la droite de Goodman dans le diagramme de Haigh, on obtient les valeurs estimées suivantes des paramètres du critère de Dang Van pour l'aluminium concerné :…”

Formulation of gradient multiaxial fatigue criteria

“…The stress gradient is then a quantity able to represent and model all those informations, notably fatigue resistance. Another explanation is related to the average stress in a representative volume element (RVE) [6], which is different between the three tests for the critical point, during a fatigue cycle. This stress is equal to the maximum stress for the tension-compression tests, whereas it is reduced by the presence of a gradient for the bending tests.…”

Fatigue of 316L stainless steel notched μm-size components

“…Calibrated material parameters, a; b, and c, and obtained correlation coefficient, R 2 . The volumetric approach considers a process volume for fatigue mechanisms [67,68] and assumes such a volume to be a cylinder for the three-dimensional specimens (slot and hole specimens) and a circle for the two-dimensional specimens (notch and fib specimens) with the center corresponding to the root of the notch. In three-dimensional structures, the cylinder is coherent with the spatial distribution of the mechanical fields.…”