PSI - Issue 2_B

ScienceDirect Available online at www.sciencedirect.com Av ilable o line at ww.sciencedire t.com ScienceDirect Structural Integrity Procedia 00 (2016) 000 – 000 Procedia Struc ural Integrity 2 (2016) 3515–3522 Available online at www.sciencedirect.com ScienceDirect Structural Integrity Procedia 00 (2016) 000–000 Available online at www.sciencedirect.com ScienceDirect Structural Integrity Procedia 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 Sh rt and long cra k growth behavior of welded ferritic stainless steel Manon Abecassis a *, Alain Köster a , Vincent Maurel a a MINES ParisTech, PSL Research University, MAT - Centre des matériaux, CNRS UMR 7633, BP 87 91003 Evry, France Abstract To analyze the influence of welding on fatigue crack growth, several geometrical configurations have been tested using notched specimens with notch located within base metal and welded joint. This methodology has shown that fatigue crack growth rate was similar for base metal and welded part for the ferritic stainless steel F18TNb (corresponding to AISI 441 or EN 1.4509 grades) considering long crack. Whereas for short crack, the microstructure induced by the welding process was evidenced to drastically increase the resulting crack growth rate. The tested configurations have been systematically modeled by finite element analysis to obtain reliable shape function and SIF assessment for the chosen geometries. Then fatigue crack growth behavior is discussed on the basis of both SIF values and the influence of microstructure in crack path and crack growth rate. © 2016 The Authors. Published by Elsevier B.V. Peer-review under responsibility of the Scientific Committee of ECF21. Keywords: Ferritic stainless steel ; weldment ; crack growth modelling ; grain size gradient 1. Introduction Ferritic stainless steels are usually used in automotive industry and often assembled by welding. Welding is well known to modify locally the microstructure as compared to the base metal (Tsukamoto, Harada, and Bhadeshia 1994; Zambon and Bonollo 1994). The welded joint consists of the base metal, the fusion zone separated by a transition area from the base metal, the so called heat affected zone. These areas have different microstructures but also exhibit dissimilar mechanical behaviors from the base metal to the welded joint (Fu and Shi 1996). Considering fatigue crack growth in the presence of welded parts, it has been established that the microstructure of the welded joint has an impact on the crack path (Ritchie 1988). The crack in the welded joint could deflect to the base metal for dissimilar steel welded joint (H. T. Wang 2013) or otherwise the crack could be straight in the welded joint and become tortuous in the base metal (Trudel, Lévesque, and Brochu 2014). Some branching and deflection were also observed for Q345 steel (Xiong and Hu 2012). As a direct consequence of the fatigue crack interaction with the microstructure inherited from the welding process, for HT80 welded steel (Ohta et al. 1982) and for 444 welded stainless steel (Akita et al. 2006), fatigue crack growth rate was observed to be different in the threshold region but to be similar in the Paris region comparing base metal and fusion zone. This point is consistent with the influence of the grain size on fatigue crack growth evidenced by (Kusko, Dupont, and Marder 2004) for a 316L austenitic stainless steel: small grain size involves lower fatigue crack growth rate than large grain size in the threshold region, whereas no significant difference was observed for fatigue crack growth rate in the Paris region for all tested different 21st European Conference on Fracture, ECF21, 20-24 June 2016, Catania, Italy Short and long crack growth behavior of welded ferritic stainless steel Manon Abecassis a *, Alain Köster a , Vincent Maurel a a MINES ParisTech, PSL Research University, MAT - Centre des matériaux, CNRS UMR 7633, BP 87 91003 Evry, France Abstract To analyze the influence of welding on fatigue crack growth, several geometrical configurations have been tested using notched specimens with notch located within base metal and welded joint. This methodology has shown that fatigue crack growth rate was similar for base metal and welded part for the ferritic stainless steel F18TNb (corresponding to AISI 441 or EN 1.4509 grades) considering long crack. Whereas for short crack, the mic ostructure induced by the w lding process was evidenced t drastically increase the resulting crack growth rate. The te ted configurations have been systematically modeled by finite element analysis to obtain reliable shape function and SIF assessment for the chosen geometries. Then f tigu crack growth behavior is discus ed on the basis of both SIF values an the influence f microstructure in crack path and crack growth rate. © 2016 The Authors. Published by Elsevier B.V. Peer-review under responsibility of the Scientific Committee of ECF21. Keywords: Ferritic stainless steel ; weldment ; crack growth modelling ; grain size gradient 1. Int o uction Ferritic stainl ss teels are usually used in automot ve industry and often assembled by w lding. W lding is well known t modify locally the microstructure s compare to the base met l (Tsuk moto, Harada, and Bhadeshia 1994; Zambon and Bonollo 1994). The welded joint con ists of the base metal, t fusion z n separated by a transiti ar a f om the base metal, the so called heat affected zone. These areas have different microstructures but also exhibit dissimilar mechanical be aviors from the base metal to the welded joint (Fu and Shi 1996). Considering fatigue crack growth in the presence of welded parts, it has been established that the microstructure of the welded joint has an impact on the crack path (Ritchie 1988). The crack in the welded joint could deflect to the base metal for dissimilar steel welded joint (H. T. Wang 2013) or otherwise the crack could be straight in the welded joint and become tortuous in the base metal (Trudel, Lévesque, and Brochu 2014). Some branching and deflection were also observed for Q345 steel (Xiong and Hu 2012). As a direct consequence of the fatigue crack interaction with the microstructure inherited from the welding process, for HT80 welded steel (Ohta et al. 1982) and for 444 welded stainless steel (Akita et al. 2006), fatigue crack growth rate was observed to be different in the threshold region but to be similar in the Paris region comparing base metal and fusion zone. This point is consistent with the influence of the grain size on fatigue crack growth evidenced by (Kusko, Dupont, and Marder 2004) for a 316L austenitic stainless steel: small grain size involves lower fatigue crack growth rate than large grain size in the threshold region, whereas no significant difference was observed for fatigue crack growth rate in the Paris region for all tested different 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/). eer-revie under respon ibility of the cientific o ittee of E F21. © 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 * Corresponding author. E-mail address: manon.abecassis@mines-paristech.fr * Corresponding author. E-mail address: manon.abecassis@mines-paristech.fr

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.2016.06.438 2452-3216 © 2016 The Authors. Published by Elsevier B.V. Peer-review under responsibility of the Scientific Committee of ECF21. 2452-3 16 © 2016 The Authors. Published by Elsevier B.V. Peer-review under respon ibility of the Scientifi Committee of ECF21.