PSI - Issue 2_A

ScienceDirect Available online at www.sciencedirect.com Av ilable o line at ww.sciencedire t.com cienceDirect Structural Integrity Procedia 00 (2016) 000 – 000 Procedia Struc ural Integrity 2 (2016) 1427–1434 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 Fatigue of NiTi shape memory wires Sebastián M. Jaureguizahar a , Mirco D. Chapetti b * and Alejandro A. Yawny a a División Física de Metales, Centro Atómico Bariloche, CNEA-CONICET, Av. Bustillo 9500, S.C. Bariloche (8400), Argentina b INTEMA (CONICET-Universidad Nacional de Mar del Plata, FI), J.B. Justo 4302 , Mar del Plata (7600), Argentina Abstract In the present work, an innovative methodology for characterizing structural fatigue of NiTi superelastic wires is proposed. It consists in, firstly, performing low speed nearly isothermal pseudoelastic cycles in a limited region of the wire specimen. This results in the stabilization of the pseudooelastic behavior accompanied by a decrease in the stresses for forward and reverse transformations which allows obtaining an equivalent to a geometric dog-bone shaped specimen due to the reduced transformation stresses in the pre-cycled region. In a second stage, by limiting the transformation active zone to the pre-cycled region, the deformation speed can be increased to practical values avoiding any transformation activity outside that region. In that way, grip induced failures resulting in artificially shorter fatigue lives might be completely avoided thus allowing an accurate characterization of the true structural fatigue. Additionally, strain controlled experiments on wires in fully austenite and fully martensite states have been performed. Resulting fatigue lives in these cases were at least two orders of magnitude higher compared with the pseudoelastic fatigue indicating the decisive role played by the stress induced transformation in determining fatigue life. The influence of testing temperature and deformation rate on fatigue life has also been evaluated © 2016 The Authors. Published by Elsevier B.V. Peer-review under responsibility of the Scientific Committee of ECF21. Keywords: shape memory NiTi wires; pull-pull fatigue test; pseudoelasticity. 1. Introduction Superelasticiy is the capacity by which some shape memory alloys (SMA) are able to be strained up to nearly 8 10% in a reversible manner. A hysteretic behavior associated with the stress-strain response is observed with the reverse transformation occurring at a lower stress level than the forward transformation [Miyazaki et al (1981-a)]. 21st European Conference on Fracture, ECF21, 20-24 June 2016, Catania, Italy Fatigue of NiTi shape memory wires Sebastián M. Jaureguizahar a , Mirco D. Chapetti b * and Alejandro A. Yawny a a División Física de Metales, Centro Atómico Bariloche, CNEA-CONICET, Av. Bustillo 9500, S.C. Bariloche (8400), Argentina b INTEMA (CONICET-Universidad Nacional de Mar del Plata, FI), J.B. Justo 4302 , Mar del Plata (7600), Argentina Abstract In the present work, an innovative methodology for characterizing structural fatigue of NiTi superelastic wires is proposed. It consists in, firstly, performing low sp ed nearl is therm l pseudoelastic cycles in a limited region of he ire specimen. This results in the abilization of the p eudooel stic behavior accompanied by a decre se in the stresses for forward and reverse transformation which all ws obtaining an equivalent to a geometric dog-bone shaped specimen due to the reduced stresses in the pre-cycled region. In a s cond st ge, by limiting the tran formation active zon to the pre-cycl region, the deformation speed can be increased to pr ctical values avoiding any transformation activity outside that region. In that way, grip induced failures resulting artificially shorter fatigue lives might be completely avo ded thu allowing an accurate characterization of the true structural f tigue. Additi nally, strain controlled experi ents on wires in f lly austenite and fully martensite states have been performed. Resulti g fatigue lives in these ases were at least two orders of mag ude higher compared with the ps udoelastic fatigue indicati the decis v role played by the stress induced transformation i det rm ning fatigue life. T e influence of testing temperature and d formation rate on fatigue life has also be n ev luated © 2016 The Authors. Published by Elsevi B.V. Peer-review under respons bility of the Scientific Committee of ECF21. Keywords: shape memory NiTi wires; pull-pull fatigue test; pseudoelasticity. 1. Introduction Superelasticiy is the capacity by which some shape memory alloys (SMA) are able to be strained up to nearly 8 10% in a reversible manner. A h steretic behavior associated with the stress-str in respon e is observed with the reverse transfo mation occurring at a lower stress level th n the forward transfo mation [Miyazaki t al (1981-a)]. Copyright © 2016 The Auth rs. Publish d by Elsevier B.V. This is an open access article u der the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-n /4.0/). Peer-review under responsibility of the Scientific Committee of ECF21. © 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 © 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.: +54-223-4816600; fax: +54-223-4810046. E-mail address: mchapetti@fi.mdp.edu.ar * Corresponding author. Tel.: +54-223-4816600; fax: +54-223-4810046. E-mail address: mchapetti@fi.mdp.edu.ar

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.2016.06.181