PSI - Issue 48

Available online at www.sciencedirect.com Available online at www.sciencedirect.com ScienceDirect Structural Integrity Procedia 00 (2023) 000–000 Available online at www.sciencedirect.com ScienceDirect Structural Integrity Procedia 00 (2023) 000–000

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

ScienceDirect

Procedia Structural Integrity 48 (2023) 119–126

© 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 IRAS 2023 organizers Abstract In the present study, a metal-physical analysis was performed, and mechanisms of occurrence of fatigue cracks in the gear of gas turbine engine reducers were studied. It was shown that the realized stress level during the operation is close to the fatigue limit of the material. Therefore, a slight change in the stress state of the gear can cause a significant scatter of durability in the region of transition from very-high-cycle fatigue to high-cycle fatigue. The previously proposed multi-mode fatigue failure model with corresponding computational algorithm allowed to introduce the possibility of developing the fatigue failure process according to the very-high-cycle fatigue mechanism with the actual size and shape of the gear and its strength parameters for rotational speeds realized during operation. © 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) 1. Introduction The occurrence of conditions for in-service fracture of structural elements in the region of very-high-cycle fatigue (VHCF) is due to multiple reasons. The first reason is that contemporary structural elements, for example, of aircrafts, have not been designed with setting the in-service life according to the VHCF criterion. In all in-service structural elements, the critical lifetime is defined either based on the safe life concept, which takes into account the “fatigue limit” level, or the damage tolerance concept, when the initiation and propagation of surface cracks in the part is allowable and in-time detectable. Second International Symposium on Risk Analysis and Safety of Complex Structures and Components (IRAS 2023) Fatigue fracture of the gears of the aircraft engine reducer Shanyavskiy A. a,b *, Nikitin I. b , Nikitin A. b , Soldatenkov A. a a Aviation Register for the Russian Federation, Airport Sheremetievo-1, PO Box 54, Moscow region, Chimkinskiy State, 141426, Russia b Institute for Computer Aided Design, 2nd Brestskaya street 19/18, Moscow, 123056, Russia Abstract In the present study, a metal-physical analysis was performed, and mechanisms of occurrence of fatigue cracks in the gear of gas turbine engine reducers were studied. It was shown that the realized stress level during the operation is close to the fatigue limit of the material. Therefore, a slight change in the stress state of the gear can cause a significant scatter of durability in the region of transition from very-high-cycle fatigue to high-cycle fatigue. The previously proposed multi-mode fatigue failure model with corresponding computational algorithm allowed to introduce the possibility of developing the fatigue failure process according to the very-high-cycle fatigue mechanism with the actual size and shape of the gear and its strength parameters for rotational speeds realized during operation. © 2023 The Authors. Published by ELSEVIER B.V. Keywords: gears; very-high-cycle fatigue; in-service failure;numerical simulation 1. Introduction The occurrence of conditions for in-service fracture of structural elements in the region of very-high-cycle fatigue (VHCF) is due to multiple reasons. The first reason is that contemporary structural elements, for example, of aircrafts, have not been designed with setting the in-service life according to the VHCF criterion. In all in-service structural elements, the critical lifetime is defined either based on the safe life concept, which takes into account the “fatigue limit” level, or the damage tolerance concept, when the initiation and propagation of surface cracks in the part is allowable and in-time detectable. Second International Symposium on Risk Analysis and Safety of Complex Structures and Components (IRAS 2023) Fatigue fracture of the gears of the aircraft engine reducer Shanyavskiy A. a,b *, Nikitin I. b , Nikitin A. b , Soldatenkov A. a a Aviation Register for the Russian Federation, Airport Sheremetievo-1, PO Box 54, Moscow region, Chimkinskiy State, 141426, Russia b Institute for Computer Aided Design, 2nd Brestskaya street 19/18, Moscow, 123056, Russia Peer-review under responsibility of the IRAS 2023 organizers Keywords: gears; very-high-cycle fatigue; in-service failure;numerical simulation

* Corresponding author. Tel.: /; fax: /. E-mail address: 106otdel@mail.ru * Corresponding author. Tel.: /; fax: /. E-mail address: 106otdel@mail.ru

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 IRAS 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 IRAS 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 IRAS 2023 organizers 10.1016/j.prostr.2023.07.137