PSI - Issue 13

ScienceDirect Available online at www.sciencedirect.com Av ilable online at www.sciencedire t.com ienceDirect Structural Integrity Procedia 00 (2016) 000 – 000 Procedia Structural Integrity 13 (2018) 1071–1 75 Available online at www.sciencedirect.com ScienceDirect Structural Integrity Procedia 00 (2018) 000 – 000 Available online at www.sciencedirect.com ScienceDirect 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. ECF22 - Loading and Environmental effects on Structural Integrity Quantification method for parameters affecting multi-scale roughness-induced fatigue crack closure To oki MIZOGUCHI a *, Motomichi KOYAMA b and Hiroshi NOGUCHI b a Graduate School of Engineering, Kyushu University, 744 Motooka, Nishi-ku, Fukuoka, 819-0371, Japan b Faculty of Engineering, Kyushu University, 744 Motooka, Nishi-ku, Fukuoka, 819-0371, Japan Our challenge is to clarify the relationship between crack roughness and microstructure. Roughness-induced crack closure (RICC) is known to be one of the main factors decelerating fatigue crack growth. Two factors trigger RICC: 1) nanometer-scale roughness on the crack surface (nano roughness) and 2) degree of crack deflection (micro-roughness). These factors affect the friction stress acting on the crack planes and the stress intensity factor range for crack closure. For instance, S. Suresh and R. O. Ritchie discussed the eff cts of geometrical mismatch between fatigue crack planes on crack closure. We further attempt to measure multi-scale crack roughness to quantitatively estimate RICC with respect to both friction and crack closure effects. In this study, we examine the multi-scale crack roughness of a lamellar-structured Fe-9Mn-3Ni-1.4Al-0.01C steel sample as a case study. We verify the effect of crack surface friction. Here, we assume that the basic effect of nano-roughness on friction is significant when the inclination angle of micro-roughness against the loading direction is less than the angle of nano-roughness. If the inclination angle of micro-roughness against the loading direction is larger than the angle of nano-roughness, the nano-roughness effect does not occur because the crack surfaces do no contact with each other. To further discuss the underlying effects of multi-scale roughness, we will present more details on the microstructure- and mechanical condition-related roughness parameters and their quantification techniques. © 2018 The Authors. Published by Elsevier B.V. Peer-review under responsibility of the ECF22 organizers. Keywords: Fatigue; Roughness-induced crack closure; In-situ fatigue test; TRIP-maraging steel Roughness is one of the factors controlling fatigue crack growth because it triggers roughness-induced crack closure (RICC) and roughness-induced stress shielding (RISS). For instance, pearlitic steels (G.T. Gray et al . 1983) and transformation-induced plasticity (TRIP) maraging steels (M. Koyama et al . 2017; Z. Zhang et al . 2017) show fatigue crack resistance associated with nano-laminate-induced microstructural crack roughness. According to previous studies (S. Suresh and R.O. Ritchie 1982), the effect of micrometer- or millimeter-scale roughness on RICC can be estimated in terms of the geometrical mismatch between fatigue crack surfaces. Figure 1 shows a schematic representation of the RICC associated with the geometrical mismatch between fatigue crack surfaces. Specifically, the height of the crack roughness and mode II shear displacement cause the geometrical mismatch, which assists crack closure. The micrometer-scale roughness is referred to as micro-roughness. In addition, sub micrometer- or nanometer-scale crack roughness coupled with micro-roughness can result in significant friction stress along the © 2018 The Authors. Published by Elsevier B.V. Peer-review under responsibility of the ECF22 organizers. ECF22 - Loading and Environmental effects on Structural Integrity Quantification method for parameters affecting multi-scale roughness-induced fatigue crack closure Tomoki MIZOGUCHI a *, Motomichi KOYAMA b and Hiroshi NOGUCHI b a Graduate School of Engineering, Kyushu University, 744 Motooka, Nishi-ku, Fuk oka, 819-0371, Japan b Faculty of Engineering, Kyushu University, 744 Motooka, Nishi-ku, Fukuoka, 819-0371, Japan Abstract Our challenge is to clarify the relationship between crack roughness and microstructure. Roughness-induced crack closure (RICC) is known to be one of the main factors decelerating fatigue crack growth. Two factors trigger RICC: 1) nanometer-scale roughness on the crack surface (nano roughness) and 2) degree of crack deflection (micro-roughness). These factors affect the friction stress acting on the crack planes and the stress intensity factor range for crack closure. For instance, S. Suresh and R. O. Ritchie discussed the effects of geometrical mismatch between fatigue crack planes on crack closure. We further attempt to measure multi-scale crack roughness to quantitatively estimate RICC with respect to both friction and crack closure effects. In this study, we examine the multi-scale crack roughness of a lamellar-structured Fe-9Mn-3Ni-1.4Al-0.01C steel sample as a case study. We verify the effect of crack surface friction. Here, we assume that the basic effect of nano-roughness on friction is significant when the inclination angle of micro-roughness against the loading direction is less than the angle of nano-roughness. If the inclination angle of micro-roughness against the loading direction is larger than the angle of nano-roughness, the nano-roughness effect does not occur because the crack surfaces do no contact with each other. To further discuss the underlying effects of multi-scale roughness, we will present more details on the microstructure- and mechanical condition-related roughness parameters and their quantification techniques. e Authors. ublished by lsevier B. . eer-revie under responsibility of the 22 organizers. Keywords: Fatigue; Roughness-i duced crack closure; In-situ fatigue test; TRIP-maraging steel 1. Int oduction Roughness is one of the factors controlling fatigue crack growth because it triggers roughness-induced crack closure (RICC) and roughness-induced stress shielding (RISS). For instance, pearlitic steels (G.T. Gray et al . 1983) and transformation-induced plasticity (TRIP) ma aging teels (M. Koyama et al . 2017; Z. Zhang et al . 2017) show fatigue crack resistance associated with nano-laminate-induced microstructural crack roughness. According to previous studies (S. Suresh and R.O. Ritchie 1982), the effect f micromet r- or millimeter-scale roughn ss on RICC can be estimated in terms of the geometrical mismatch between fatigue crack surfaces. Figure 1 shows a schematic representation of the RICC associated with the geometrical is atch bet een fatigue crack surfaces. Specifically, the height of the crack roughness and mode II shear displacement cause the geometrical mismatch, which assists crack closure. The micrometer-scale roughness is referred to as micro-roughness. In addition, sub icrometer- or nanometer-scale crack roughness coupled with micro-roughness can result in significant friction stress along the © 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. Abstract 1. Introduction

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-revi w under respon ibility of the ECF22 organizers. 2452-3216 © 2018 The Authors. Published by Elsevier B.V. Peer-review under responsibility of the ECF22 organizers. * Corresponding author. Tel.: +351 218419991. E-mail address: amd@tecnico.ulisboa.pt * Corresponding author. Tel.: +81-92-802-3141; fax: +81-92-802-0001. E-mail address: 3TE18803M@s.kyushu-u.ac.jp * Corresponding author. Tel.: +81-92-802-3141; fax: +81-92-802-0001. E-mail address: 3TE18803M@s.kyushu-u.ac.jp

2452-3216  2018 The Authors. Published by Elsevier B.V. Peer-review under responsibility of the ECF22 organizers. 10.1016/j.prostr.2018.12.225