PSI - Issue 13

ScienceDirect Available online at www.sciencedirect.com Av ilable o line at www.sciencedire t.com ScienceDirect Structural Integrity Procedia 00 (2016) 000 – 000 Procedia Structural Integrity 13 (2018) 101 –1 13 Available online at www.sciencedirect.com ScienceDirect Structural Integrity Procedia 00 (2018) 000 – 000 Available online at www.sciencedirect.com ScienceDirect Structural I tegrity 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. ECF22 - Loading and Environmental effects on Structural Integrity Emergence of distinct fatigue limit: impact of excess solute magnesium in 6061-T6 alloy Yoshimasa Takahashi a, *, Ry suke Kuriki a , Masaki Kashiha a a , Takahiro Shikama b , Hiroshi Noguchi c a Department of Mechanical Engineering, Kansai University, 3-3-35 Yamate-cho, Suita-shi, Osaka 564-8680, Japan b Kobe Steel Ltd., Aluminum & Copper Business (Chofu Works), 14-1 Chofu Minato-machi, Shimonoseki,Yamaguchi 752-0953, Japan c Department of Mechanical Engineering, Kyushu University, 744 Motooka, Nishi-ku, Fukuoka 819-0395, Japan Abstract The fatigue properties of 6061-T6 aluminum (Al) alloy containing additional solute magnesium (Mg) is studied. As previously reported, this special alloy exhibits eminent strain-aging characteristics which is absent in a normal 6061-T6 alloy with a stoichiometric Mg 2 Si composition. In this study, particular attention is paid to the environmental effect on the fatigue properties of this new alloy. The S - N curves of the alloys are compared in different environments (ambient air, dry air, dry nitrogen). A clear knee-point (fatigue limit), which is atypical to the normal 6061-T6 alloy, appears for the new alloy irrespective of the environment. The fatigue limit is shown to be controlled by the threshold against small crack propagation in all environments. On the other hand, the coaxi g effect, the m nif station f a tim -dependent strengthen g mechanism at the non- ropagating crack tip, is learly observed in the ambie t air. © 2018 The Authors. Published by Elsevier B.V. Peer-review under responsibility of the ECF22 organizers. Keywords: Distinct fatigue limit; Aluminum alloys; 6061-T6; Strain aging; Extra magnesium; Environmental effect The existence of a distinct knee-point (fatigue limit) in the stress-life ( S - N ) diagram is one of the mechanical characteristics of ferrous steels. From an engineering viewpoint, such a characteristic (i.e. cycle- independent strength) is useful as it can be used as a cl ar index of desig stress value for structural components subjected to fatigue load. © 2018 The Authors. Published by Elsevier B.V. Peer-review under responsibility of the ECF22 organizers. ECF22 - Loading and Environmental effects on Structural Integrity Emergence of distinct fatigue limit: impact of excess solute magnesium in 6061-T6 alloy Yoshimasa Takahashi a, *, Ryosuke Kuriki a , Masaki Kashihara a , Takahiro Shikama b , Hiroshi Noguchi c a Department of Mechanical Engineering, Kansai University, 3-3-35 Yamate-cho, Suita-shi, Osaka 564-8680, Japan b Kobe Steel Ltd., Aluminum & Copper Business (Chofu Works), 14-1 Chofu Minato-machi, Shimonoseki,Yamaguchi 752-0953, Japan c Department of Mechanical Eng ering, Kyushu University, 744 oto ka, Nishi-ku, Fukuo a 819-0395, Japan Abstract The fatigue properties of 6061-T6 aluminum (Al) alloy containing additional solute magnesium (Mg) is studied. As previously reported, this s cial alloy exhibits e inent strain-aging characteristics which is abse t in a normal 6061-T6 alloy with a stoichiometric Mg 2 Si composition. In this study, particular attention is paid to the environmental effect on the fatigue properties of this new alloy. The S - N curves of t e alloys are compared in different environments (ambient air, dry air, dry nitrogen). A clear knee-point (fatigue limit), which is atypic l to the normal 6061-T6 alloy, appears for the new alloy irrespective of the environm nt. The f ti li it is shown to be controlled by the threshold against small crack propagation in all environm nts. On the other hand, the coaxing effect, the manifestation of a time-dependent stre gthening mechanism t the on-propagating crack tip, is clearly observed in the ambient air. © 2018 The Authors. Published by Elsevier B.V. Peer-review under responsibility of the ECF22 organizers. Keywords: Distinct fatigue limit; Aluminum alloys; 6061-T6; Strain aging; Extra magnesium; Environmental effect 1. Introduction The existence f a distinct knee-point (fatigue limit) in the stress-life ( S - N ) diagram is one of the mechanical characteristics of ferrous teels. From an eng neering viewpoint, such a characteristic (i.e. cycle- independent strength) is useful as it can be used as a clear index of design stress value for structural components subjected to fatigue load. © 2016 The Authors. Published by Elsevier B.V. Peer-review under responsibility of the Scientific Committee of PCF 2016. Keywords: High Pressure Turbine Blade; Creep; Finite Element Method; 3D Model; Simulation. 1. Introduction

* Corresponding author. Tel.: +351 218419991. E-mail address: amd@tecnico.ulisboa.pt 2452-3216 © 2018 The Authors. Published by Elsevier B.V. Peer-review under responsibility of the ECF22 organizers. 2452-3216 © 2018 The Authors. Published by Elsevier B.V. Peer review under r sponsibility of the ECF22 organizers. * Corresponding author. Tel.: +81-6-6368-0748; fax: +81-6-6368-0748. E-mail address: yoshim-t@kansai-u.ac.jp * Corresponding author. Tel.: +81-6-6368-0748; fax: +81-6-6368-0748. E-mail ad ress: yoshim-t@kansai 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  2018 The Authors. Published by Elsevier B.V. Peer-review under responsibility of the ECF22 organizers. 10.1016/j.prostr.2018.12.188