PSI - Issue 2_A

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) 2734–2741 Available online at www.sciencedirect.com Sc nceDir ct 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 crack growth in round bars for ock anchorages: the role of residual stresses Jesús Toribio*, Juan-Carlos Matos, Beatriz González, José Escuadra Fracture and Structural Integrity Research Group, University of Salamanca, E.P.S., Campus Viriato, Avda. Requejo 33, 49022 Zamora, Spain Abstract The role of different residual stress profiles in the fatigue crack growth is studied in prestressing steel wires under tension loading or bending moment. The crack front evolutio is analyzed by means of a computer program on the basis of the Walker law. Numerical results indicate that the absence of residual stresses makes the crack propagate following a preferential cracking path. When surface residual stresses are tensile and, correspondingly, core residual stresses are compressive, the fatigue crack fronts rapidly converge towards a quasi-straight shape. When surface residual stresses are compressive, with their corresponding tensile stresses in the core area, a preferential cracking path also appears. © 2016 The Authors. Published by Elsevier B.V. Peer-review under responsibility of the Scientific Committee of ECF21. Keywords: Round bars; semi-elliptical surface cracks; numerical modelling; Walker law; residual stress profile; fatigue crack propagation 1. Introduction High-strength cold-draw pre tressing steel wires, frequently used as components of anchor g in rocks, are manufactured from hot rolled pearlitic steel bars and have excellent mechanical properties. As studied by Toribio and Valiente (2004), the cold drawing process improves the mechanical properties of the material by increasing the yield strength, the ultimate tensile strength (UTS), the fracture toughness, etc. Elices (2004) showed that such a manufacturing technique induces strong tensile residual stresses at the wire surface and compressive ones in the core. In the papers by He et al. (2003) and Atienza et al. (2005), it is shown that the residual stress distribution in cold drawn wires can be evaluated by experimental methods (e.g., neutron and X-ray diffraction techniques) and by numerical procedures such as the finite element method (FEM). In the work by Atienza et al. (2005), the isotropic von Mises 21st European Conference on Fracture, ECF21, 20-24 June 2016, Catania, Italy Fatigue crack growth in round bars for rock anchorages: the role of residual stresses Jesús Toribio*, Juan-Carlos Matos, Beatriz González, José Escuadra Fracture and Structural Integrity Research Group, University of Salamanca, E.P.S., Campus Viriato, Avda. Requejo 33, 49022 Zamora, Spain Abstract The role of different residual stress profiles in the fatigue crack growth is studied in prestressing steel wires under tension loading or bending mom . The crack front evolution is analyzed by means of a compute program on the ba is of th Walker law. Numerical results indicate that the abs nce of residual str sses makes the crack propagate followi g a preferential cracking p th When surface re idual s resses ar tensile and, correspondingly, core residual stresses are compressive, the fatigue crack fronts rapidly conv rg tow rds a quasi-straight shape. Wh n surface residual stresses a compr ssive, with their corresponding tensile stresses in th core area, a preferen i l cracking path also appears. © 2016 The Authors. Published by Elsevier B.V. Peer-review under espons bility of the Scientific Committee of ECF21. Keywords: Round bars; semi-elliptical surface cracks; numerical m delling; Walker law; r sidual stress profile; fatigue crack pr pagation 1. Introduction High-strength cold-drawn prestressing steel wires, frequently used as components of anchorage in rocks, are manuf ctu d from ot rolled pearlitic steel bars and have exc llent mech nical p p r ies. As studied by Toribio nd V liente (2004), the cold drawing pro ess improves t e m cha ical propert es of the material by increasing the yiel strength, the ultimate tensile strength (UTS), the fracture toughness, etc. Elices (2004) show d that such a ma ufacturing technique i duce strong tensile residual stresses at t e wire surface and compres ive ones in the ore. In the pape s by He et al. (2003) and Atienza et al. (2005), it i shown that the residu l stress distributi in cold drawn wires c n be evaluated by experimental methods e.g., neutron and X-ray diffraction t chn ques) and by numerical procedures such as he finite element method (FEM). I the work by Atienza et al. (2005), th isotropic von M ses 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. © 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 und r 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.: +34-980-545000; fax: +34-980-545002. E-mail address: toribio@usal.es * Corresponding author. Tel.: +34-980-545000; fax: +34-980-545002. E-mail address: toribio@usal.es

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.2016.06.341