PSI - Issue 19

Available online at www.sciencedirect.com Structural Int grity Procedia 00 (2019) 000 – 000 Available online at www.sciencedirect.com ScienceDirect Structural Integrity Procedia 00 (2019) 000 – 000 Available online at www.sciencedirect.com ScienceDirect

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Procedia Structural Integrity 19 (2019) 19–26

Fatigue Design 2019 An alternative approach to calibrate multiaxial fatigue models of steels with small defects L.C. Araujo a *, P.V.S. Machado a , M.V.S Pereira b , J.A. Araújo a a University of Brasília, Departament of Mechanical Engineerinng, Brasília, DF 70910-900, Brazil b Catholic University of Rio de Janeiro, Department of Chemical and Materials Engineering, Rio de Janeiro, RJ 22453-901, Brazil Fatigue Design 2019 An alternative approach to calibrate multiaxial fatigue models of steels with small defects L.C. Araujo a *, P.V.S. Machado a , M.V.S Pereira b , J.A. Araújo a a University of Brasília, e rtament of Mechanical Engineerinng, Brasília, DF 70910-900, Brazil b Catholic University of Rio de Janeiro, Department of Chemical and Materials Engineering, Rio de Janeiro, RJ 22453-901, Brazil In this work the authors propose a new methodology to estimate threshold loading conditions for naturally defective steels under complex stress states. In this setting, multiaxial fatigue models based on the critical plane approach and in the stress invariant approach are adapted to assess the effect of non-metallic inclusions in the material. In order to do so, it will be used a method that relates the √ parameter of a small defect and the Vickers hardness of the material ( ) with the nominal fatigue limit for this material either under uniaxial ( ) or under torsional ( ) loading. Therefore, uniaxial and torsional fatigue limits usually required to calibrate the multiaxial criteria will be calculated by the √ parameter. With this methodology the multiaxial fatigue criteria utilized are not changed. However, calibrating them is considerably cheaper and faster compared to traditional methods. To assess the new methodology, combined axial-torsional multiaxial fatigue data in DIN 42CrMo6 steel generated by the authors will be used. The proposed methodology is compared to the experiments and agreement within 5% error bands were obtained. In this work the authors propose a new methodology to estimate threshold loading conditions for naturally defective steels under complex stress states. In this setting, multiaxial fatigue models based on the critical plane approach and in the stress invariant approach are adapted to assess the effect of non-metallic inclusions in the material. In order to do so, it will be used a method that relates the √ parameter of a small defect and the Vickers hardness of the material ( ) with the nominal fatigue limit for this material either under uniaxial ( ) or under torsional ( ) loading. Therefore, uniaxial and torsional fatigue limits usually required to calibrate the multiaxial criteria will be calculated by the √ parameter. With this methodology the multiaxial fatigue criteria utilized are not changed. However, calibrating the is considerably cheaper and faster compared to traditional methods. To assess the new methodology, combined axial-torsional multiaxial fatigue data in DIN 42CrMo6 steel generated by the authors will be used. The proposed methodology is compared to the experiments and agreement within 5% error bands were obtained. Abstract Abstract

© 2019 The Authors. Published by Elsevier B.V. Peer-review under responsibility of the Fatigue Design 2019 Organizers. © 2019 The Authors. Published by Elsevier B.V. Peer-review under responsibility of the Fatigue Design 2019 Organizers. © 2019 The Authors. Published by Elsevier B.V. Peer-review under responsibility of the Fatigue Design 2019 Organizers. Keywords: non-metallic inclusions; defective materials; multiaxial fatigue; small defects. Keywords: non-metallic inclusions; defective materials; multiaxial fatigue; small defects.

1. Introduction 1. Introduction

The effect of small defects and nonmetallic inclusions on fatigue strength of materials has been the object of study The effect of small defects and nonmetallic inclusions on fatigue strength of materials has been the object of study

* Corresponding author. Tel.: +55 61 31071148; fax: +55 61 31075707. E-mail address: lucasc.araujo@aluno.unb.br (L.C. Araujo), pedromachado@aluno.unb.br (P.V.S. Machado), marcospe@puc-rio.br (M.V.S Pereira), alex07@unb.br (J.A. Araújo). * Correspon ing author. Tel.: +55 61 31071148; fax: +55 61 31075707. E-mail address: lucasc.araujo@aluno.unb.br (L.C. Araujo), pedromachado@aluno.unb.br (P.V.S. Machado), marcospe@puc-rio.br (M.V.S Pereira), alex07@unb.br (J.A. Araújo).

2452-3216 © 2019 The Authors. Published by Elsevier B.V. Peer-review under responsibility of the Fatigue Design 2019 Organizers. 2452-3216 © 2019 The Authors. Published by Elsevier B.V. Peer-review under responsibility of the Fatigue Design 2019 Organizers.

2452-3216 © 2019 The Authors. Published by Elsevier B.V. Peer-review under responsibility of the Fatigue Design 2019 Organizers. 10.1016/j.prostr.2019.12.004