PSI - Issue 3

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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. Copyright © 2017 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 IGF Ex-Co. XXIV Italian Group of Fracture Conference, 1-3 March 2017, Urbino, Italy Recording the mechanical response and fracture of marble DENT specimens using modern sensing techniques S. K. Kourkoulis a, *, D. Triantis b , I. Stavrakas b , E. D. Pasiou a and I. Dakanali a a Laboratory for Testing and Materials, National Technical University of Athens, Zografou Campus 157 73, Greece b Laboratory of Electronic Devices and Materials, Technological Educational Institution of Athens, Athens 122 10, Greece Abstract The mechanical response and fracture of Double Edged Notched Tensile (DENT) specimens, made of Dionysos marble, is studied in an effort to enlighten the mechanisms activated before and during catastrophic crack initiation and propagation in pre-cracked structures. The innovation of the study is that four modern sensing techniques, both contact and non-contact, are used simultaneously to monitor the response of the specimens, in the direction of pumping real-time data from both the surface and the interior of them. The analysis of these data, permitted comparative assessment of the efficiency of the techniques used and indicated that they pro vide clear and in mutual agreement signs, which precede the onset of crack initiation and can be considered as pre-failure indicators. © 2017 The Authors. Published by Elsevier B.V. Peer-review under responsibility of the Scientific Committee of IGF Ex-Co. Keywords: Dionysos marble; “DENT” specimens; AE; Pressure Stimulated Currents; Digital Image Correlation; High speed camera, Monuments 1. Introduction The study of the mechanical response and fracture of pre-notched real structures is a challenging task, especially from the analytic point of view, due to both the stress concentration around the tip (crown) of the notch and also due to the interaction f the notch with the boundaries of the specimen (in case the length of the notch is not negligible with respect to the dimensions of the structures). Analytic solutions for the stress concentration around circular and elliptic notches are available already from the beginning of previous century (Kirsch 1898, Inglis 1913), however they are valid only for “infinite” plates or equivalently for “small” notches. The problem concerns the engineering communi ty long ago because the stress concentration is crucial in order to safely design structures of any kind (Li & Guo 2001). XXIV Italian Group of Fracture Conference, 1-3 March 2017, Urbino, Italy Recording the echanical response and fracture of marble DENT speci ens using odern sensing techniques S. K. Kourkoulis a, *, D. Triantis b , I. Stavrakas b , E. D. Pasiou a and I. Dakanali a a Laboratory for Testing and M terials, National Technical University of Athens, Zografou Campus 157 73, Greece b Laboratory of Electronic Devices and Materials, Technological Educational Institution of Athens, Athens 122 10, Greece Abstract The mechanical response and fracture of Double Edged Notched Tensile (DENT) specimens, made of Dionysos marble, is studied in an effort to enlighten the mechanisms activated before and during catastrophic crack initiation and propagation in pre-cracked structures. The innovation of the study is that four modern sensing techniques, both contact and non-contact, are used simultaneously to monitor the response of the specimens, in the direction of pumping real-time data from both the surface and the interior of them. The analysis of these data, permitted comparative assessment of the efficiency of the techniques used and indicated that they pro vide clear and in mutual agreement signs, which precede the onset of crack initiation and can be considered as pre-failure indicators. © 2017 The Authors. Publi hed by Elsevier B.V. Peer-review under responsibility of the Scie tific Committee of IGF Ex-Co. Keywords: Dionysos marble; “DENT” specimens; AE; Pressure Stimulated Currents; Digital Image Correlation; High speed camera, Monuments 1. Intro uction The study of th mechanical respon e nd fracture of pr -notched re l s ructures is a challenging task, especially from the a alytic poi t of view, due to both the stress concentration around the tip (crown) of the notch and also due to the interaction of the notch with the boundaries of the specimen (in case the length of the notch is not negligible with respect to the dimensions of the structures). Analytic solutions for the stress concentration around circular and elliptic notches are available already from the beginning of previous century (Kirsch 1898, Inglis 1913), however they are valid only for “infinite” plates or equivalently for “small” notches. The problem concerns the engineering communi ty long ago because the stress concentration is crucial in order to safely design structures of any kind (Li & Guo 2001). © 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.: +30 210 772 1263; fax: +30 210 772 1264. E-mail address: stakkour@central.ntua.gr * Corresponding author. Tel.: +30 210 772 1263; fax: +30 210 772 1264. E-mail address: stakkour@central.ntua.gr

* Corresponding author. Tel.: +351 218419991. E-mail address: amd@tecnico.ulisboa.pt 2452-3216 © 2017 The Authors. Published by Elsevier B.V. Peer-review under responsibility of the Scientific Committee of IGF Ex-Co. 2452-3216 © 2017 The Authors. Published by Elsevier B.V. Peer-review under responsibility of the Scientific Committee of IGF Ex-Co.

2452-3216 © 2016 The Authors. Published by Elsevier B.V. Peer-review under responsibility of the Scientific Committee of PCF 2016. Copyright © 2017 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 IGF Ex-Co. 10.1016/j.prostr.2017.04.017