PSI - Issue 14

ScienceDirect Available online at www.sciencedirect.com Av ilable o line at ww.sciencedire t.com ienceDirect Structural Integrity Procedia 00 (2016) 000 – 000 Procedi Structural Integrity 14 9 11–17 ScienceDirect Structural Integrity Procedia 00 (2018) 000 – 000 Available online at www.sciencedirect.com Sci nceDirect Structural Integrity Procedia 00 (2018) 000 – 000

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XV Portuguese Conference on Fracture, PCF 2016, 10-12 February 2016, Paço de Arcos, Portugal Thermo-mechanical modeling of a high pressure turbine blade of an airplane gas turbine engine P. Brandão a , V. Infante b , A.M. Deus c * a Department of Mechanical Engineering, Instituto Superior Técnico, Universidade de Lisboa, Av. Rovisco Pais, 1, 1049-001 Lisboa, Portugal b IDMEC, Department of Mechanical Engineering, Instituto Superior Técnico, Universidade de Lisboa, Av. Rovisco Pais, 1, 1049-001 Lisboa, Portugal c CeFEMA, Department of Mechanical Engineering, Instituto Superior Técnico, Universidade de Lisboa, Av. Rovisco Pais, 1, 1049-001 Lisboa, Portugal Abstract During their operation, modern aircraft engine components are subjected to increasingly demanding operating conditions, especially the high pressure turbine (HPT) blades. Such conditions cause these parts to undergo different types of time-dependent degradation, one of which is creep. A model using the finite element method (FEM) was developed, in order to be able to predict the creep behaviour of HPT blades. Flight data records (FDR) for a specific aircraft, provided by a commercial aviation company, were used to obtain thermal and mechanical data for three different flight cycles. In order to create the 3D model needed for the FEM analysis, a HPT blade scrap was scanned, and its chemical composition and material properties were obtained. The data that was gathered was fed into the FEM model and different simulations were run, first with a simplified 3D rectangular block shape, in order to better establish the model, and then with the real 3D mesh obtained from the blade scrap. The overall expected behaviour in terms of displacement was observed, in particular at the trailing edge of the blade. Therefore such a model can be useful in the goal of predicting turbine blade life, given a set of FDR data. 2nd International Conference on Structural Integrity and Exhibition 2018 Crack size dependency of shear-mode fatigue threshold in bearing steel subjected to continuous hydrogen charging Y. Akaki a , T Matsuo b, c *, Y. Nishimura d and S. Miyakawa d a Graduate School of Engineering, Fukuoka University 8-19-1 Nanakuma, Jonan-ku, Fukuoka 814-0180, Japan b Development of Mechanical Engineering, Fukuoka University 8-19-1 Nanakuma, Jonan-ku, Fukuoka 814-0180, Japan c Institute of Materials Science and Technology, Fukuoka University 8-19-1 Nanakuma, Jonan-ku, Fukuoka 814-0180, Japan d Materials Engineering R&D Division, DENSO CORPORATION, Japan 1-1 Syowa-cho, Kariya, Aichi 448-8661, Japan Premature delamination failure, characterized by the white structure flaking (WSF) or the white etching crack (WEC), often occurs in rolling element bearings and it deteriorates the durability of bearing substantially. It is known that this failure is caused by shear-mode (Mode II and Mode III) crack growth in conjunction with evolution and invasion of hydrogen into material during operation. To ensure the structural integrity associated with rolling element bearing, it is important to clarify the effect of hydrogen on the shear-mode fatigue crack growth behavior near the threshold level. In our previous study, the effect of hydrogen on the shear-mode fatigue crack growth behavior in a bearing steel of JIS SUJ2 was examined near the threshold level. Consequently, it was shown that the threshold stress intensity factor (SIF) range for shear mode fatigue crack growth decreased significantly by action of hydrogen. However, the investigation was made only for a crack with a surface le gth of about 900  m. To thoroughly understand the critical condition for lamination failure, it is important to investigat the crack size dependency of the t reshold level for a shear-mode small f tigue crack in the presence of hydrogen. In the present study, corresp ndingly, the threshold SIF r nges for a sh ar-mode crack with different l ngth wer additionally measur d in the same material by using a novel technique that e ables continuous charging of hydr gen in a spec men during long term fatigue test. Then, cle r reduction in crack growth rate and a crack size dependency of the threshold SIF range were observed under the environment l co dition of continuous hydrogen charging. © 2018 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/) Selectio and peer-review n er responsibility of the SICE 2018 organizers. 2nd International Conference on Structural Integrity and Exhibition 2018 Crack size dependency of shear-mode fatigue threshold in bearing steel subjected to continuous hydrogen charging Y. Akaki a , T Matsuo b, c *, Y. Nishimura d and S. Miyakawa d a Graduate School of Engineering, Fukuoka University 8-19-1 Nanakuma, Jonan-ku, Fukuoka 814-0180, Japan b Development of Mechanical Engineering, Fukuoka University 8-19-1 Nanakuma, Jonan-ku, Fukuoka 814-0180, Japan c Institute of Materials Science and Technology, Fukuoka University 8-19-1 Nanakuma, Jonan-ku, Fukuoka 814-0180, Japan d Materials Engineering R&D Division, DENSO CORPORATION, Japan 1-1 Syowa-cho, Kariya, Aichi 448-8661, Japan Abstract Premature delamination failure, characterized by the white structure flaking (WSF) or the white etching crack (WEC), often occurs in rolling element bearings and it deteriorates the durability of bearing substantially. It is known that this failure is caused by shear-mode (Mode II and Mode III) crack growth in conjunction with evolution and invasion of hydrogen into material during operation. To ensure the structural integrity associated with rolling element bearing, it is important to clarify the effect of hydrogen on the shear-mode fatigue crack growth behavior near the threshold level. In our previous study, the eff ct of hydrogen on the shear-mode fatigue rack growth behavior in bearing steel of JIS SUJ2 was examined near the threshold level. Consequently, it was shown that the threshold stress intensity factor (SIF) range for shear mode fatigue crack growth decreased significantly by action of hydrogen. However, the investigation was made only for a crack with a surface length of about 900  m. To thoroughly understand the critical condition for delamination failure, it is important to investigate the crack size dependency of the threshold level for a shear-mode small fatigue crack in the presence of hydrogen. In the present study, correspondingly, the threshold SIF ranges for a shear-mode crack with different length were additionally measured in the same material by using a novel technique that enables continuous charging of hydrogen in a specimen during long term fatigue test. Then, a clear reduction in crack growth rate and a crack size dependency of the threshold SIF range were observed under the environmental condition of continuous hydrogen charging. © 2018 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/) Selection and peer-review under responsibility of the SICE 2018 organizers. © 2016 The Authors. Published by Elsevier B.V. Peer-review under responsibility of the Scientific Committee of PCF 2016. © 2019 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/) Selection and peer-review under responsibility of Peer-review under responsibility of the SICE 2018 organizers. Abstract

Keywords: High Pressure Turbine Blade; Creep; Finite Element Method; 3D Model; Simulation.

* Corresponding author. Tel.: +81-92-871-6631(Ext. 6320); fax: +81-92-865-6031. E-mail address: tmatsuo@fukuoka-u.ac.jp * Corresponding author. Tel.: +81-92-871-6631(Ext. 6320); fax: +81-92-865-6031. E-mail address: tmatsuo@fukuoka-u.ac.jp

2452-3216 © 2016 The Authors. Published by Elsevier B.V. Peer-review under responsibility of the Scientific Committee of PCF 2016. 2452-3216  2019 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/) Selection and peer-review under responsibility of Peer-review under responsibility of the SICE 2018 organizers. 10.1016/j.prostr.2019.05.003 2452-3216 © 2018 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/) Selection and peer-review under responsibility of Peer-review under responsibility of the SICE 2018 organizers. 2452-3216 © 2018 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/) Selection and peer-review under responsibility of Peer-review under responsibility of the SICE 2018 organizers. * Corresponding author. Tel.: +351 218419991. E-mail address: amd@tecnico.ulisboa.pt