PSI - Issue 57

Available online at www.sciencedirect.com Available online at www.sciencedirect.com ScienceDirect Structural Integrity Procedia 00 (2022) 000 – 000 Available online at www.sciencedirect.com ScienceDirect Structural Integrity Procedia 00 (2022) 000 – 000

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Procedia Structural Integrity 57 (2024) 144–151

© 2024 The Authors. Published by Elsevier B.V. This is an open access article under the CC BY-NC-ND license (https://creativecommons.org/licenses/by-nc-nd/4.0 ) Peer-review under responsibility of the scientific committee of the Fatigue Design 2023 organizers Abstract A new multiaxial fatigue model for materials containing small defects proposed by the authors is presented, which one can be considered as a modification of the SWT model. This new model relates the fatigue limit of the material obtained from the √ parameter with values associated with the principal stresses. These values are the amplitude of the principal stresses and the maximum principal stress observed. The amplitude value associated with the principal stresses is defined by using the Maximum Variance Method. This amplitude only can be easily obtained under uniaxial loading conditions, but its calculation for torsion, proportional and non-proportional multiaxial loadings is not trivial. Therefore, the calculation of the principal stress amplitude posed a challenge not yet addressed by other authors. The multiaxial fatigue model was evaluated with experimental data from AISI 4140 steel, with several different loading conditions, including uniaxial loading, combined loads in in-phase and out-of phase configurations. In addition, two types of specimens were used: smooth cylindrical specimens and specimens with a surface micro hole. Comparing the experimental data with the prediction of the new model it was observed that the predictions are slightly conservative with average error not exceeding 6%. © 2023 The Authors. Published by ELSEVIER B.V. This is an open access article under the CC BY-NC-ND license (https://creativecommons.org/licenses/by-nc-nd/4.0) Peer-review under responsibility of the scientific committee of the Fatigue Design 2023 organizers Keywords: multiaxial fatigue; new model; small defects; principal stress amplitude; maximum variance method. Fatigue Design 2023 (FatDes 2023) Assessing Fatigue in Materials with Small Defects: A New Multiaxial Model Based on Principal Stress Amplitudes Lucas Carneiro Araujo a, *, Jorge Luiz de Almeida Ferreira a , Maksym Ziberov a , José Alexander Araújo a a Department of Mechanical Engineering,University of Brasília,Faculdade de Tecnologia, Campus Universitário Darcy Ribeiro, Asa Norte, Brasília - DF, 70910-900, Brazil Abstract A new multiaxial fatigue model for materials containing small defects proposed by the authors is presented, which one can be considered as a modification of the SWT model. This new model relates the fatigue limit of the material obtained from the √ parameter with values associated with the principal stresses. These values are the amplitude of the principal stresses and the maximum principal stress observed. The amplitude value associated with the principal stresses is defined by using the Maximum Variance Method. This amplitude only can be easily obtained under uniaxial loading conditions, but its calculation for torsion, proportional and non-proportional multiaxial loadings is not trivial. Therefore, the calculation of the principal stress amplitude posed a challenge not yet addressed by other authors. The multiaxial fatigue model was evaluated with experimental data from AISI 4140 steel, with several different loading conditions, including uniaxial loading, combined loads in in-phase and out-of phase configurations. In addition, two types of specimens were used: smooth cylindrical specimens and specimens with a surface micro hole. Comparing the experimental data with the prediction of the new model it was observed that the predictions are slightly conservative with average error not exceeding 6%. © 2023 The Authors. Published by ELSEVIER B.V. This is an open access article under the CC BY-NC-ND license (https://creativecommons.org/licenses/by-nc-nd/4.0) Peer-review under responsibility of the scientific committee of the Fatigue Design 2023 organizers Keywords: multiaxial fatigue; new model; small defects; principal stress amplitude; maximum variance method. Fatigue Design 2023 (FatDes 2023) Assessing Fatigue in Materials with Small Defects: A New Multiaxial Model Based on Principal Stress Amplitudes Lucas Carneiro Araujo a, *, Jorge Luiz de Almeida Ferreira a , Maksym Ziberov a , José Alexander Araújo a a Department of Mechanical Engineering,University of Brasília,Faculdade de Tecnologia, Campus Universitário Darcy Ribeiro, Asa Norte, Brasília - DF, 70910-900, Brazil

* Corresponding author. Tel.: +55 62 98228-1885. E-mail address: carneiroaraujol@gmail.com * Corresponding author. Tel.: +55 62 98228-1885. E-mail address: carneiroaraujol@gmail.com

2452-3216 © 2023 The Authors. Published by ELSEVIER B.V. This is an open access article under the CC BY-NC-ND license (https://creativecommons.org/licenses/by-nc-nd/4.0) Peer-review under responsibility of the scientific committee of the Fatigue Design 2023 organizers 2452-3216 © 2023 The Authors. Published by ELSEVIER B.V. This is an open access article under the CC BY-NC-ND license (https://creativecommons.org/licenses/by-nc-nd/4.0) Peer-review under responsibility of the scientific committee of the Fatigue Design 2023 organizers

2452-3216 © 2024 The Authors. Published by ELSEVIER B.V. This is an open access article under the CC BY-NC-ND license (https://creativecommons.org/licenses/by-nc-nd/4.0) Peer-review under responsibility of the scientific committee of the Fatigue Design 2023 organizers 10.1016/j.prostr.2024.03.017