PSI - Issue 12

ScienceDirect Available online at www.sciencedirect.com Av ilable online at ww.sciencedire t.com ScienceDirect Structural Integrity Procedia 00 (2016) 000 – 000 Procedia Structu al Integrity 12 (2018) 13 –144 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. AIAS 2018 International Conference on Stress Analysis Experiment based modeling of the mechanical expansion of tubes for the construction of heat exchangers Massimiliano Avalle a *, Alessandro Scattina b a Università degli Studi di Genova, Via all’Opera Pia 15, 16145 Genova, Italy b Politecnico di Torino, Corso Duca degli Abruzzi 24, 10129 Torino, Italy Tube heat exchangers are made by assembling metals tubes, which the fluid to be refrigerated is passed through, with fins where a refrigerating fluid (usually air) is flown over. The heat exchange between tubes and fins is obtained by exploiting their tight contact. This necessary very tight contact is obtained by means of brazing (typically in smaller equipment) or through the forced expansion of the tubes into the fins holes. The forced expansion can be hydraulic (by some fluid put in pressure in the assembly operation) or mechanic through the insertion of a sphere or an ogive with external diameter slightly larger than the internal diameter of the tube. The sphere or the ogive is pushed along the entire length of the tube so that the tube remains plastically forced i to th fins holes. The process is then repeated for all the tub s of the heat exchanger. Th resent work concentrates on th mechanic l xpansion: to optimize the construction process it is necessary t have a model able to describe th mechanical phenomenon: that is, to evaluat the stress state in the tube uring the se tion f the ogive, the residual stresses after the sphere/ogive passage, and the force required de ending on the r cess and materials parameters (including the geometry of the tube, ogive, an fins, their material properties, friction, insertion speed etc.). The present work will describe an analytical model able to describe the process with a good level of predictability showing the effect of the main parameters involved in the process. The model is based and validated by means of experimental tests and numerical simulations at different levels and in different conditions and materials. © 2018 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/3.0/) Peer-review under responsibility of the Scientific Committee of AIAS 2018 International Conference on Stress Analysis. © 2018 The Author . 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/3.0/) Peer-review under responsibility of the Scientific Committee of AIAS 2018 International Conference on Stress Analysis. AIAS 2018 International Conference on Stress Analysis Experiment based modeling of the mechanical expansion of tubes fo th cons ruction of heat exchangers Massimiliano Avalle a *, Alessandro Scattina b a Università degli Studi di Genova, Via all’Opera Pia 15, 16145 Genova, Italy b Politecnico d Torino, Cors Duca degli Ab uzz 24, 10129 Tori , Italy Abstract Tube heat exchangers are made by assembling metals tubes, which the fluid to be refrigerated is passed through, with fins where a refrig rating fluid (usually air) is flown over. The heat exchange b tween tu s and fins is obt in by exploiting their tight contact. Th s necessary ver tight contact is obtained by m ans of brazing (typically in smaller equipment) or through t forced expansion of the tubes into the fins holes. The force expansion can be hydraulic (by so e fluid put in pressure in t e assembly operation) r mechanic through the insertion of a sphere or an ogiv with external diameter slightly larger than the internal diamete of the tube. The sphere or the ogive is pu hed al ng the entire length of the tube so that the tube em i s plastically forced int the fins holes. The p ocess is then repeated for ll the tub s of th heat exc anger. The p esen work conc ntrat s on the mechanical expansion: to optimize construction process it is ecessary to have a model able to d scribe t e mechanical phe o non: that is, to evaluate the str ss state in the tube uring the ins rtion of t e ogive, the residual stress s after t e sphere/ogive passage, and the force requi ed dep nding on the process a d materials parameters (incl ding the geom try of the tube, ogive, and fins, their material properties, friction, insertion speed etc.). The present work will describe an analytic l model able to describe the process with a good level of predictability showing the eff ct of the main parameters involved in the process. The model is based and validated by means of experimental tests and numerical simulations t differe t le els a d in different conditi ns and materi ls. © 2018 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/3.0/) Peer-review u der responsibility of t Scientific ommitt e of AIAS 2018 Internati al Conference on Stress Analysis. © 2016 The Authors. Published by Elsevier B.V. Peer-review under responsibility of the Scientific Committee of PCF 2016. Keywords: tube expansion process; analytical model; parametric analysis Abstract

Keywords: High Pressure Turbine Blade; Creep; Finite Element Method; 3D Model; Simulation. Keywords: tube expansion process; analytical model; parametric analysis

* Corresponding author. Tel.: +39-010-3532241; fax: +39-010-3532834. E-mail address: massimiliano.avalle@unige.it * Corresponding author. Tel.: +39-010-3532241; fax: +39-010-3532834. E-mail ad ress: massimiliano.avalle@unige.it

2452-3216 © 2018 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/3.0/) Peer-revi w u er responsibility of the Scientific Committee of AIAS 2018 International Conference on Stress Analysis. 2452-3216 © 2018 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/3.0/) Peer-review u der re ponsibility of Scientific ommitt e of AIAS 2018 Internati al Conference on Stress Analysis.

* Corresponding author. Tel.: +351 218419991. E-mail address: amd@tecnico.ulisboa.pt

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. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/3.0/) Peer-review under responsibility of the Scientific Committee of AIAS 2018 International Conference on Stress Analysis. 10.1016/j.prostr.2018.11.100