PSI - Issue 2_A

ScienceDirect Available online at www.sciencedirect.com Av ilable o line at ww.sciencedire t.com ienceDirect Structural Integrity Procedia 00 (2016) 000 – 000 Procedia Structu al Integrity 2 (2016) 565–572 Available online at www.sciencedirect.com Structur l Int ity Procedia 00 (2016) 0 –000 Available online at www.sciencedirect.com Structural Integrity Procedia 00 (2016) 000–000 vailable online at .sciencedirect.com Structural Integrity rocedia 00 (2016) 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. 21st European Conference on Fracture, ECF21, 20-24 June 2016, Catania, Italy Continuum level simulation of the grain size and misorientation effects on hydrogen embrittlement in nickel Haiyang Yu a , Jim Stian Olsen a , Jianying He a , Zhiliang Zhang a, ∗ a Norwegian University of Science and Engineering, Richard Birkelands vei 1a, Trondheim 7491, Norway Abstract This paper addresses the size and misorientation effects on hydrogen embrittlement of a four grain nickel aggregate. The grain interior is modelled with orthotropic elasticity and the grain boundary with cohesive zone technique. The grain misorientation angle is parameterized by fixing the l wer grains and rotating the upper grains about the out of-plane axis. The hydrogen effect is accounted for via the three-step hydrogen informed c hesive zone simulation. The grain misorientation exerts an obvious weakening effect on the ultimate strength of the nickel aggregate which reaches its peak at misorientation angles around 20 ◦ , but such effect becomes less pronounced in the case with a pre-crack. The misorientation could induce size effect in the otherwise size independent case without a pre-crack. The contribution of misorientation to the size effect is negligible compare to that caused by the existence of a pre crack. These findings indicate that the misorientation effect in cases with a deep pre-crack is weaker than expected in shallow-pre-crack situations. Most of these conclusions hold for the hydrogen charging situation except that the ultimate strength is lowered in all the sub-cases due to hydrogen embrittlement. Interestingly, it is observed that the size effect becomes less pronounced with hydrogen taken into account, which is caused by the fact that hydrogen takes more time to reach the failure initiation site in larger grains. c 2016 The Authors. Published by Elsevier B.V. Peer-review under responsibility of the Scientific Committee of ECF21. Keywords: Hydrogen embrittlement; nickel; grain misorientation; cohesive zone modelling; size effect. 21st European Conference on Fracture, ECF21, 20-24 June 2016, Catania, Italy Contin um level simul tion of the grain size and misorientation effects on hydrogen embrittlement in nickel Haiyang Yu a , Jim Stian Olsen a , Jianying He a , Zhiliang Zhang a, ∗ a Norwegian University of Science and Engineering, Richard Birkelands vei 1a, Trondheim 7491, Norway Abstract is p per address s the size and misorie tation effects on hydrogen embrittlement of a four grain nickel aggregate. The grain interior is mod lled with orthotropic elasticity and the grain bound ry with cohesive zo e technique. The grain misorientation angle is parameterized by fixing the lowe grains an rotating the upper grains about the out of-plane axis. The hydrogen effect is account d for via the three-step hydrogen informed cohesive zone simulation. The grain misorientation exerts an obvious weakening effect on the ultimate strength f the nickel aggregate hich reaches its peak at misorientation angles around 20 ◦ , but such effect becomes less pronounced in the case with a pre-crack. The misorientation could induce size ffect in the otherwise size independent case without a pre-crack. The contribution of misorientation to the size effect is n gligible compare to that caused by th existence of a pre crack. These findings indicate that the misorientation effect in cases with a deep pre-crack is weaker than expec ed in sh llow-pre-crack situations. Most of these conclusions hold for the hydrogen charging situation except h the ultimate strength is lowered in all the sub-cases due o hydrogen embrittlement. Interestingly, it is observed that the size effect becomes less pronounced wi h hydrog n taken into account, which is caused by the fact that hydrogen takes more time to reach the failure initiation site in larger grains. c 2016 The Authors. Published by Elsevier B.V. Peer-review under responsibility of the Scientific Co mittee of ECF21. Keywords: Hydrogen embrittlement; nickel; grain misorientation; cohesive zone modelling; size effect. i l l i l i f i i i i i i l i i l Haiyang Yu a , im Stian Olsen a , i i e a , ili a, ∗ a or egian niversity of Science and ngineering, ichard irkelands vei 1a, rondhei 7491, or ay stract This paper ddresses the size and isorientation effects on hydrogen embrittlement of a four grain nickel aggregate. he grain interior is modelled with orthotropic elasticity and the grain boundary with cohesive zone technique. The grain misorientation angle is para eterized by fixing the lo er grains and rotating the upper grains about the out of-plane axis. he hydrogen effect is accounted for via the three-step hydrogen infor ed cohesive zone si ulation. The grain isorientation exerts an obvious eakening effect on the ulti ate strength of the nickel aggregate hich reaches its peak at isorientation angles around 20 ◦ , but such effect beco es less pronounced in the case ith a pre-crack. he isorientation could induce size effect in the other ise size independent case ithout a pre-crack. The contribution of isorientation to the size effect is negligible co pare to that caused by the existence of a pre crack. hese findings indicate that the isorientation effect in cases ith a deep pre-crack is eaker than expected in shallo -pre-crack situations. ost of these conclusions hold for th hydrogen charging situation except that the ulti ate strength is lo ered in all the sub-cases due to hydrogen e brittle ent. Interestingly, it is observed that the size effect beco es less pronounced ith hydrogen taken into account, hich is caused by the fact that hydrogen takes ore ti e to reach the failure initiation site in larger grains. c 2016 he uthors. ublished by lsevier . . Peer-revie under responsibility of the Scientific o ittee of ECF21. Key ords: ydrogen e brittle ent; nickel; grain isorientatio ; cohesive zon odelling; size effect. Copyright © 2016 The Authors. Published by Elsevier B.V. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/b -nc-nd/4.0/). P er-review under r spon ibility of the Scientific Comm ttee of ECF21.

© 2016 The Authors. Published by Elsevier B.V. Peer-review under responsibility of the Scientific Committee of PCF 2016. Nomenclat re

Nomenclature Nomenclature

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

* Corresponding author. Tel.: +351 218419991. E-mail address: amd@tecnico.ulisboa.pt ritical cohesive separation Γ C cohesive separation energy critical cohesive separation Γ C cohesive separation energy half pre-crack length half pr -crack length ohesive strength σ C cohesive strength δ C critical cohesive separation Γ C cohesive separation energy δ grain misorientation angle misorientation angle grain isorientation angle grain length half pre-crack length grain length grain l ngth cohesive strength θ θ θ L a σ L L a a σ δ

2452-3216 © 2016 The Authors. Published by Elsevier B.V. Peer-review under responsibility of the Scientific Committee of PCF 2016. Copyright © 2016 The Authors. Published by Elsevier B.V. This is an open access article under the CC BY-NC-ND license ( http://creativecommons.org/licenses/by-nc-nd/4.0/ ). Peer review under responsibility of the Scientific Committee of ECF21. 10.1016/j.prostr.2016.06.073 ∗ Corresponding author. Tel.: +47 73592530. E-mail address: zhiliang.zhang@ntnu.no 2452-3216 c 2016 Th Authors. Published by Elsevier B.V. Peer-review under responsibility of the Scientific Committee of ECF21. ∗ Corresponding author. Tel.: +47 73592530. E-mail address: zhiliang.zhang@ntnu.no 2452-3216 c 2016 The Authors. Published by Elsevier B.V. eer-re i er responsibility of the Scientific Co mittee of ECF21. ∗ orresponding author. el.: 47 73592530. - ail address: zhiliang.zhang ntnu.no 2452-3216 c 2016 The Authors. Published by Elsevier B.V. Peer-review under responsibility of the Scientific Committee of ECF21.