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) 1522–1529 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 Optimization Of The Fatigue Resistance Of Nitinol Stents Through Shot Peening Konstantinos Dimakos*, Andrea Mariotto, Fausto Giacosa R&D Department, Cardiac Surgery Business Unit, Sorin Group Italia Srl (LivaNova), Via Crescentino, Saluggia (VC), 13040, Italy “ Nitinol ” (NiTi) is an intermetallic alloy of approximately equal atomic percentages of nickel and titanium that is widely used in less invasive and self-expanding implantable medical devices such as cardiovascular stents, due to its superelastic, shape memory and biocompatibility properties. Most of its applications in the medical industry involve the application of repeated stresses or strain cycles that drive the need of increasing the fatigue and fracture resistance of this alloy. The Nitinol stent supporting a biological heart valve prosthesis is considered one such example and is the critical structural component in many of the heart valve prostheses. Continuous effort is made to increase the fatigue resistance of these cardiac devices through experimenting with various manufacturing a d surface treatment techniques. This study proves that the shot peening (SP) process improves he fatigu resistance of Nitinol stents and also describes the effect f different pe ning intensities on th treated ur aces, through the application of the Almen test. © 2016 The Authors. Published by Elsevier B.V. Peer-review under responsibility of the Scientific Committee of ECF21. Keywords: Nitinol stents; Bioprosthetic heart valves; Fatigue resistance; Shot peening; Almen test Copyright © 2016 The Auth rs. Published by Elsevier B.V. This is an open access articl u der 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. Abstract

1. Introduction

© 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. Nitinol is a unique metal alloy composed of nickel and titanium at approximately equal atomic percentages, that exhibits extraordinary material properties, with its highlights being its superelasticity and shape memory effects (Stoeckel, 1998). In other words, it shows superior elasticity under stress, approximately 10 to 20 times more than

* Corresponding author. Tel.: +39-344-1329-658 E-mail address: konstantinos.dimakos@livanova.com

* 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 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.2016.06.193