PSI - Issue 10

ScienceDirect Available online at www.sciencedirect.com Av ilable o line at ww.sciencedire t.com ienceDirect Structural Integrity Procedia 00 (2016) 000 – 000 Procedia Structu al Integrity 1 (2018) 163–17 Available online at www.sciencedirect.com ScienceDirect Structural Integrity Procedia 00 (2018) 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. © 2018 The Authors. Published by Elsevier Ltd. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/3.0/) Peer-review under responsibility of the scientific committee of the 1st International Conference of the Greek Society of Experimental Mechanics of Materials. 1 st International Conference of the Greek Society of Experimental Mechanics of Materials Contact length in discs and rings by the reflected caustics method Ch.F. Markides* Laboratory for Testing and Materials, Department of Mechanics, School of Applied Mathematical and Physical Sciences, National Technical University of Athens, 5, Heroes of Polytechnion Avenue, Theocaris Building, Zografou Campus, 157 73 Athens, Greece Abstract Based on the existing analytic solution of two cylindrical bodies in contact, the method of reflected caustics is here employed to obtain the contact length, realized between disc/rings, made of a transparent optically isotropic elastic material, and the jaws of the International Society for Rock Mechanics (ISRM)’ standardized apparatus for the implementation of the Brazilian-disc test. In this context, assuming a negligible refraction index, because of a small thickness of the specimen, the equations of caustics are here rederived, giving emphasis to those due to light reflection from the rear face of the specimen. Revealing some further features relating reflected caustics from the front and rear face of the disc, the contact length is obtained in closed form by the aid of an existing simple linear formula, usually ignored because of unspecified data, defined here in the light of the new evidence. © 2018 The Auth rs. Published by Elsevier Ltd. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/3.0/). Peer-review under responsibility of the scientific committee of the 1 st International Conference of the Greek Society of Experimental Mechanics of Materials Keywords: Reflected caustics; contact problem; transparent optically isotropic materials; Brazilian disc 1. Introduction The undiminished interest of scientific community in caustics over the past decades shows that the method constitutes over ime a powerful tool in the field of material science. That is because the method offers high accuracy demanding the least experimental equipment at low cost. Τ he underlying principle of the method is that light reflected from a polished surface of an illuminated stressed body forms wave fronts intersected in space along highly luminous curves the caustics, exhibiting features closely related to the induced stress field. First introduced by Manogg (1964) Authors. Published by Elsevier Ltd. This is an open access article under the CC BY-NC-ND license (http://creativecommons.o t curves the caustics, exhibiting features c © 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.

* Tel.: +30 210 7721313; fax: +30 210 7721302. E-mail address: markidih@mail.ntua.gr Received: April 30, 2018; Received in revised form: July 08, 2018; Accepted: July 13, 2018 Received: Ap

2452-3216 © 2016 The Authors. Published by Elsevier B.V. Peer-review under responsibility of the Scientific Committee of PCF 2016. 2452-3216  2018 The Authors. Published by Elsevier Ltd. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/3.0/) Peer-review under responsibility of the scientific committee of the 1st International Conference of the Greek Society of Experimental Mechanics of Materials. 10.1016/j.prostr.2018.09.024 2452- 3216 © 2018 The Authors. Published by Elsevier Ltd. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/3.0/). Peer-review under responsibility of the scientific committee of the 1 st International Conference of the Greek Society of Experimental Mechanics of Materials * Corresponding author. Tel.: +351 218419991. E-mail address: amd@tecnico.ulisboa.pt