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On fatigue limit in the presence of notches: classical vs. recent unified formulations

On fatigue limit in the presence of notches: classical vs. recent unified formulations
On fatigue limit in the presence of notches: classical vs. recent unified formulations
Classical formulations for the fatigue strength reduction factor of notched specimen, Kf, (such as those by Neuber, Peterson, Heywood) were developed long time ago and have found some success by introducing a material constant (dependent on the tensile strength only) in order to take into account the problem of notch sensitivity. However, being empirical fitting equations, they have serious limitations when their asymptotic behaviour is considered, or when the empirical constants are not directly calibrated with experiments. This is shown in this work by using example data taken from the literature for various steels and alloys, and various notch sizes and shapes.
Furthermore, although the material constants can be modified to include fatigue threshold dependence (satisfying the requirements of fracture mechanics), only the Neuber formula has a correct functional form in the entire range of notch sizes and shapes, and indeed appears to be sufficiently conservative in the range of data considered.
Improved accuracy is found with a more recent empirical criterion due to Atzori and Lazzarin based on the Smith and Miller classification of notches, and with a new criterion here obtained by making consistent the Atzori and Lazzarin with the Luká–Klesnil, having a sound interpretation in terms of self-arrested cracks ahead of a rounded notch for which the Creager–Paris stress field is valid. A large number of experimental data are taken from the literature to compare the accuracies of the various criteria.
0142-1123
289-298
Ciavarella, Michele
3de51b62-4f69-4369-9f4d-a743d6950daa
Meneghetti, Giovanni
7e1872c4-28f3-4898-a90e-a4512d929bc2
Ciavarella, Michele
3de51b62-4f69-4369-9f4d-a743d6950daa
Meneghetti, Giovanni
7e1872c4-28f3-4898-a90e-a4512d929bc2

Ciavarella, Michele and Meneghetti, Giovanni (2004) On fatigue limit in the presence of notches: classical vs. recent unified formulations. International Journal of Fatigue, 26 (3), 289-298. (doi:10.1016/S0142-1123(03)00106-3).

Record type: Article

Abstract

Classical formulations for the fatigue strength reduction factor of notched specimen, Kf, (such as those by Neuber, Peterson, Heywood) were developed long time ago and have found some success by introducing a material constant (dependent on the tensile strength only) in order to take into account the problem of notch sensitivity. However, being empirical fitting equations, they have serious limitations when their asymptotic behaviour is considered, or when the empirical constants are not directly calibrated with experiments. This is shown in this work by using example data taken from the literature for various steels and alloys, and various notch sizes and shapes.
Furthermore, although the material constants can be modified to include fatigue threshold dependence (satisfying the requirements of fracture mechanics), only the Neuber formula has a correct functional form in the entire range of notch sizes and shapes, and indeed appears to be sufficiently conservative in the range of data considered.
Improved accuracy is found with a more recent empirical criterion due to Atzori and Lazzarin based on the Smith and Miller classification of notches, and with a new criterion here obtained by making consistent the Atzori and Lazzarin with the Luká–Klesnil, having a sound interpretation in terms of self-arrested cracks ahead of a rounded notch for which the Creager–Paris stress field is valid. A large number of experimental data are taken from the literature to compare the accuracies of the various criteria.

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Published date: 2004

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Local EPrints ID: 23224
URI: http://eprints.soton.ac.uk/id/eprint/23224
ISSN: 0142-1123
PURE UUID: 5588d669-a9b2-4491-8a55-fe2ce3191fca

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Date deposited: 24 Mar 2006
Last modified: 15 Mar 2024 06:45

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Author: Michele Ciavarella
Author: Giovanni Meneghetti

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