PSI - Issue 68

ScienceDirect Structural Integrity Procedia 00 (2025) 000–000 Structural Integrity Procedia 00 (2025) 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 68 (2025) 453–457

European Conference on Fracture 2024 Regularities of fatigue crack initiation and growth in two-phases titanium alloy after beach mark formation under VHCF regime Shanyavskiy A. a,b *, Nikitin A. a , Nikitin I. a a Institute for computer aided design of the Russian Academy of Sciences, 19/18, 2nd Brestskaya st., Moscow, 123056, Russia b Aviation Register for the Russian Federation, Airport Sheremetievo-1, PO Box 54, Moscow region, 4 Chimkinskiy State, 141426, Russia Abstract The paper introduces the results of fatigue crack growth (FCG) tests under high-frequency loading (20 kHz). The FCG tests are performed in stepwise decreasing of stress intensity factor (SIF) value. The morphology of the obtained fracture surfaces is investigated by scanning electron microscopy (SEM). The study is focused on the analysis of local areas located just ahead from crack tip (beach marks). These marks are reflecting the forced stop of the cyclic loading during the FCG test for correction the stress intensity factor value. Results of SEM observations shows the fatigue crack ‘re-initiation’ just ahead of these beach marks in the bulk of material after the start of new cyclic loading. This new crack nucleation takes place from the boundary junction of neighboring alpha-phase or cleaved single alpha-phase. The discovered mechanism of fatigue crack growth was implemented in the mathematical model. The numerical simulation of crack front shape under high-frequency loading shows a suitable agreement between the prediction and experimental results. © 2025 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 ECF24 organizers Keywords: VHCF ; crack growth ; crack propagation ; in service failure ; turbine disk. 1. Introduction The experience in the analysis of the aircraft engine in-service failures show a notable amount of compressor disk fractures made of two-phase titanium alloys by Shanyavskiy (2005) and Shanysvskiy (2021). The common scenario of such fractures is following: the fatigue crack initiated at rim part of the compressor disk in the dovetail region by European Conference on Fracture 2024 Regularities of fatigue crack initiation and growth in two-phases titanium alloy after beach mark formation under VHCF regime Shanyavskiy A. a,b *, Nikitin A. a , Nikitin I. a a Institute for computer aided design of the Russian Academy of Sciences, 19/18, 2nd Brestskaya st., Moscow, 123056, Russia b Aviation Register for the Russian Federation, Airport Sheremetievo-1, PO Box 54, Moscow region, 4 Chimkinskiy State, 141426, Russia Abstract The paper introduces the results of fatigue crack growth (FCG) tests under high-frequency loading (20 kHz). The FCG tests are performed in stepwise decreasing of stress intensity factor (SIF) value. The morphology of the obtained fracture surfaces is investigated by scanning electron microscopy (SEM). The study is focused on the analysis of local areas located just ahead from crack tip (beach marks). These marks are reflecting the forced stop of the cyclic loading during the FCG test for correction the stress intensity factor value. Results of SEM observations shows the fatigue crack ‘re-initiation’ just ahead of these beach marks in the bulk of material after the start of new cyclic loading. This new crack nucleation takes place from the boundary junction of neighboring alpha-phase or cleaved single alpha-phase. The discovered mechanism of fatigue crack growth was implemented in the mathematical model. The numerical simulation of crack front shape under high-frequency loading shows a suitable agreement between the prediction and experimental results. © 2025 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 ECF24 organizers Keywords: VHCF ; crack growth ; crack propagation ; in service failure ; turbine disk. 1. Introduction The experience in the analysis of the aircraft engine in-service failures show a notable amount of compressor disk fractures made of two-phase titanium alloys by Shanyavskiy (2005) and Shanysvskiy (2021). The common scenario of such fractures is following: the fatigue crack initiated at rim part of the compressor disk in the dovetail region by © 2025 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 ECF24 organizers

* Corresponding author E-mail address: 106otdel@mail.ru * Corresponding author E-mail address: 106otdel@mail.ru

2452-3216 © 2025 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 ECF24 organizers 2452-3216 © 2025 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 ECF24 organizers

2452-3216 © 2025 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 ECF24 organizers 10.1016/j.prostr.2025.06.081