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) 1148–1153 Available online at www.sciencedirect.com ScienceDirect Structural Integrity Procedia 00 (2018) 000 – 000 Available online at www.sciencedirect.com ScienceDirect Structura Integrity Proced a 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. © 2018 The Authors. Published by Elsevier B.V. Peer-review under responsibility of the ECF22 organizers. ECF22 - Loading and Environmental effects on Structural Integrity Analysis of fatigue crack configuration influence on fatigue life Masataka Aibara a * , Motomichi Koyama b , Shigeru Hamada b and Hiroshi Noguchi b a Graduate School of Engineering, Kyushu University, 744 Motooka, Nishi-ku, Fukuoka, 819-0395, Japan b Faculty of Engineering, Kyushu University, 744 Motooka, Nishi-ku, Fukuoka, 819-0395,Japan Abstract When a crack initiates and grows in a plain specimen under constant cyclic load amplitude, fatigue crack growth behavior is not reproducible. The fatigue crack length l 0 when the scatter of the fatigue crack growth rate converges is reported by observing the crack growth behavior on the specimen surface. The l 0 is reported that it is approximately six times as long as the grain size in carbon steels. Howev r, the crack sh pe of the nside is n t observed a d we considered that the three-dimensional irregular fat gue crack front shape affects the fatigue crack growth behavior on the specimen surface. Furthermore, the physical meaning and controlling factors of the l 0 is still uncertain . Therefore, in this study, we propose two factors that affect the local fatigue crack growth rate: local microstructural and mechanical factors. The former causes a variation of the three-dimensional fatigue crack front hape, and the fatigue crack front shape synergistically affects the mechanical condition at the crack tip. Then we investigated the stress intensity factor values along the tip of the crack including a part of the locally grown crack front. And we propose a concept of force caused by a stable growth part which preve ts loc l growth parts from growing. © 2018 The Authors. Published by Elsevi r B.V. Peer-review under responsibility of the ECF22 organizers. Keywords: fatigue crack growth simulation; stress intensity factor; finit element method; crack front shape; 1. Introduction Because engineering metals are composed of polycrystalline microstructures, the local fatigue crack growth rate (FCGR) varies, even under the same mechanical conditions. Goto et al. (1992) measured the fatigue crack length on the specimen surfaces of many materials using the replica method, and they found that the scatter of the crack growth rate converges rapidly from a certain crack length. The fa igue crack length which the scatter is decreased is denoted as 0 . The 0 is reported that it is approximately six times as long as the grain size in carbon steels. Omura et al. (2017) ECF22 - Loading and Environmental effects on Structural Integrity Analysis of fatigue crack configuration influence on fatigue life Masataka Aibara a * , Motomichi Koyama b , Shigeru Hamada b and Hiroshi Noguchi b a Graduate School of Engineering, Kyushu University, 744 Motooka, Nishi-ku, Fukuoka, 819-0395, Japan b F culty f Engineering, Kyushu University, 744 Motooka, Nishi-ku, F kuoka, 819-03 5,Japan Abstract When a crack initiates and grows in a plain specimen under constant cyclic load amplitude, fatigue crack growth behavior is not reproducible. The fatigue crack length l 0 when the scatter of the fati ue crack growth rate converges is reported by observing the crack growth behavior on th specime surface. The l 0 is reported that it is approxim t ly six times a long as the grain size in carbon steels. However, the crack shape of the inside is not observed and we considered that the three-dimensional irre ular fatigue rack front shape affects the fatigue crack growth behavior on the specime surface. Furthermore, the physical meaning and controlling factors of the l 0 is still uncertain . Therefore, in this study, we propose two factors that affect the local fatigue crack growth rate: local microstructural and mechanical factors. The former causes a variation of the three-dimensi n l f ti r front shape, and the fatigue crack front shape synergistically affects the mechanical condition at the crack tip. The we investigated the stress intensity factor values al g the tip of the cr ck including a part of the locally grown crac front. And we propose a concept of force caused by a stable growth part which prevents local growth parts from growing. © 2018 The Authors. Published by Elsevier B.V. Peer-review under responsibility of the ECF22 organizers. Keywords: fatigue crack growth simulation; stress intensity factor; finit element method; crack front shape; 1. Introduction Because engineering metals are composed of polycrystalline microstructures, the local fatigue crack growth rate (FCGR) varies, even under the same m chanical conditions. Goto et al. (1992) measured the fatigue crack length on the specimen surfac of many materials using the replica method, and they found that the scatter of the crack growth rate converges rapidly fro a certain crack length. The fatigue crack length at which the scatter is decreased is denoted as 0 . The 0 is reported that it is approximately six times as long as the grain size in carbon steels. Omura et al. (2017) © 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.

* 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 responsibility of the ECF22 organizers. * Corresponding author. Tel.: +81-92-802-7677; fax: +81-92-802-0001. E-mail address: masatakanike0711@gmail.com * Corresponding author. Tel.: +81-92-802-7677; fax: +81-92-802-0001. E-mail address: masatakanike0711@gmail.com

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.2018.12.239