PSI - Issue 51

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

www.elsevier.com/locate/procedia www.elsevier.com/locate/procedia

Procedia Structural Integrity 51 (2023) 152–159

© 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 ICSID 2022 Organizers Abstract In order to investigate the notch effect on the structural characteristics of the carburized 17CrNi high-strength steel in the very high cycle fatigue (VHCF) loading, the axial tests with the stress ratio ( R ) of ‒1 were performed and the S-N characteristics were studied. The microscopic observation revealed that surface induced failure was the only failure mode. Further, the effect of the notch was investigated: Based on the small crack theory, the calculation of the fatigue notch factor ( K f ) was performed and has shown that K f is slightly less than the theoretical stress concentration factor ( K t ). Then, K f was used to study both the notch effect and stress ratio effect on fatigue life. Finally, the life prediction model associated with R and K f was established and the calculation results are valid according to the good agreement with the experimental data. © 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 ICSID 2022 Organizers Keywords: Very high cycle fatigue; notch factor; crack morphology; stress radio; life prediction 1. Introduction Understanding notch-related failure is crucial for the design of reliable engineering structures. However, substantial controversies exist in the literature on the notch effect in the Very High Cycle Fatigue (VHCF) characteristics of high strength steels, and the underlying physical mechanism responsible for the apparent confusion is still poorly understood. 6th International Conference on Structural Integrity and Durability (ICSID 2022) Effect of notch and stress ratio on Very High Cycle Fatigue characteristics of the carburized 17CrNi high-strength steel and life prediction Abdelhak Nehila a, * , Wei Li b a Space Technology Research Division, Centre for Satellite Technology and Development, Algerian Space Agency, Oran 31130, Algeria b School of Mechanical Engineering, Beijing Institute of Technology, Beijing 100081, China Abstract In order to investigate the notch effect on the structural characteristics of the carburized 17CrNi high-strength steel in the very high cycle fatigue (VHCF) loading, the axial tests with the stress ratio ( R ) of ‒1 were performed and the S-N characteristics were studied. The microscopic observation revealed that surface induced failure was the only failure mode. Further, the effect of the notch was investigated: Based on the small crack theory, the calculation of the fatigue notch factor ( K f ) was performed and has shown that K f is slightly less than the theoretical stress concentration factor ( K t ). Then, K f was used to study both the notch effect and stress ratio effect on fatigue life. Finally, the life prediction model associated with R and K f was established and the calculation results are valid according to the good agreement with the experimental data. © 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 ICSID 2022 Organizers Keywords: Very high cycle fatigue; notch factor; crack morphology; stress radio; life prediction 1. Introduction Understanding notch-related failure is crucial for the design of reliable engineering structures. However, substantial controversies exist in the literature on the notch effect in the Very High Cycle Fatigue (VHCF) characteristics of high strength steels, and the underlying physical mechanism responsible for the apparent confusion is still poorly understood. 6th International Conference on Structural Integrity and Durability (ICSID 2022) Effect of notch and stress ratio on Very High Cycle Fatigue characteristics of the carburized 17CrNi high-strength steel and life prediction Abdelhak Nehila a, * , Wei Li b a Space Technology Research Division, Centre for Satellite Technology and Development, Algerian Space Agency, Oran 31130, Algeria b School of Mechanical Engineering, Beijing Institute of Technology, Beijing 100081, China

* Corresponding author. Tel.: +213-665-555-560-35. E-mail address: anehila@cds.asal.dz * Corresponding author. Tel.: +213-665-555-560-35. E-mail address: anehila@cds.asal.dz

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 ICSID 2022 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 ICSID 2022 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 ICSID 2022 Organizers 10.1016/j.prostr.2023.10.082