PSI - Issue 2_A

ScienceDirect Available online at www.sciencedirect.com Av ilable o line at ww.sciencedire t.com Scie ceDirect Structural Integrity Procedia 00 (2016) 000 – 000 Procedia Struc ural Integrity 2 (2016) 3684–3696 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 A new yield criteria incl ding the effect of lode angle and stress triaxiality G. Mirone a *, R. Barbagallo a , D. Corallo a a University of Catania, Dept. of Industrial Engineering, Viale A. Doria 6, 95125, Catania, Italy Abstract According to several experiments reported in the literature, the elastoplastic behaviour of metals depends not only on the first stress invariant (triaxiality) for the ductile damage and on the second stress invariant (equivalent von Mises stress) for the yield, but also on the third stress invariant (normalized Lode angle X) which may affect at the same time the yielding and the ductile failure. In this paper a new yield model is presented, where the yield surface depends on the Lode Angle and, eventually, also on the triaxiality ratio. The roposed model is identified by a calibration parameter expressing the degree of nonlinearity of the yield with respect to th Lode angle, and a calibration function expressing the maximum variability of the hardening stress at the two extremities of the Lode angle range, corresponding to the uniaxial and to the pure shear stress states. The proposed model has been tested against several experimental data from the literature on the Titanium alloy Ti6Al4V, including mixed tension-torsion loading which allowed to control the evolution of X and to confine its values into different narrow ranges for better investigating the Lode angle effects on the yield response. © 2016 The Authors. Published by Elsevier B.V. Peer-review under responsibility of the Scientific Committee of ECF21. 21st European Conference on Fracture, ECF21, 20-24 June 2016, Catania, Italy A new yield criteria including the effect of lode angle and stress triaxiality G. Mirone a *, R. Barbagallo a , D. Corallo a a University of Catania, Dept. of Industrial Engineering, Viale A. Doria 6, 95125, Catania, Italy Abstract According to several experiments reported in the literature, the elastoplastic behaviour of metals depends not only on the first stress invariant (triaxiality) for the ductil damag and on the s cond stre s invari nt (equival nt von Mises stress) for the yield, but also on the third stress invariant (normalized Lode a gle X) which may affect at the sam time the yielding and the ductile failure. In thi p per a new yield model is presented, where the yield surface depends on the Lode Angle and, eventually, also on the triaxiality ratio. The proposed m d l is identified by alibration para eter xpressing th d gree of nonlinearity of the yield with respect to he Lode ang e, and a calibration f nction expressing the aximum variability of th harden g stress at the two extremiti s of a e r ge, c rresponding to the uniaxial and to the pure she stress states. The proposed model has bee tested against several ex eriment l data from the literature on the Titanium alloy Ti6Al4V, including mixed tension-torsion loading which allowed to control the evolution of X nd to confine its values into different narrow ranges for better investigating the Lode angle effects on the yield response. © 2016 The Authors. Published by Elsevier B.V. Peer-review under espons bility of the Scientific Committee of ECF21. Keywords: Yield stress, elastoplastic hardening, triaxiality, Lode angle Copyright © 2016 The Authors. Published by Elsevier B.V. This is an open access article under the CC BY-NC-ND license (http://creativ commons.org/licenses/by-nc-nd/4.0/). Peer-review und r responsibility of the Scient fic Committe of ECF21.

© 2016 The Authors. Published by Elsevier B.V. Peer-review under responsibility of the Scientific Committee of PCF 2016. Keywords: Yield stress, elastoplastic hardening, triaxiality, Lode angle

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 © 2016 The Authors. Published by Elsevier B.V. Peer-review under responsibility of the Scientific Committee of ECF21. 2452-3216 © 2016 The Authors. Published by Elsevier B.V. Peer-review under responsibility of the Scientific Committee of ECF21. * Corresponding author. Tel.: +39-95-7382418; fax: +39-95-330258. E-mail address: gmirone@dii.unict.it * Corresponding author. Tel.: +39-95-7382418; fax: +39-95-330258. E-mail address: gmirone@dii.unict.it

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.2016.06.458