PSI - Issue 10

ScienceDirect Available online at www.sciencedirect.com Av ilable o line at ww.sciencedire t.com Sci ceDirect Structural Integrity Procedia 00 (2016) 000 – 000 Procedia Structu al Integrity 1 (2018) 112–119 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 Multistage triaxial testing of various rock types: A case study of East Attica Prefecture, Greece D. Kotsanis, P.P. Nomikos*, D. Rozos, A.I. Sofianos School of Mining and Metallurgical Engineering, National Technical University of Athens, 9 Iroon Polytechniou street, Athens 15780, Greece Abstract This paper presents the statistical processing of data obtained from multistage triaxial tests of selected rock types from East Attica Prefecture of Greece. Two strength models for the peak and residual strength were fitted to the experimental data, i.e., the Mohr - Coulomb criterion and the Hoek - Brown criterion. The derived strength parameters for these distinct states of stress are compared with findings of other researchers and their dramatic change during the residual state of the rock samples is discussed. © 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 I t rnational Conference of the Greek Soci ty of Experi e tal Mechanics of Mater als Keywords: Triaxial strength; failure criteria; Mohr-Coulomb; Hoek-Brown; peak strength; residual strength 1. Introduction The conventional triaxial test has been used for many years in order to obtain an insight into the mechanical behav iour of rock subjected to a three-dimensional state of str ss. In te ts, a rock specimen is subjected to a compressive stress state in which the maximum principal stress is increased at a constant rate and the other two principal stresses are of equal magnitude, i.e., σ 1 > σ 2 = σ 3 >0, where positive stresses indicate compression. Although such a stress field is not particularly common in the subsurface, as is indicated by Jaeger et al. (2007), it is commonly used in rock mechanics laboratories due to necessity which results from experimental restrictions. From the results of this test a f selected r td. t Intr ion © 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 1662 E-mail address: nomikos@metal.ntua.gr Received: May 09, 2018; Received in revised form: July 10, 2018; Accepted: July 19, 2018 * Corresponding author. Tel.: +30 210 772 1662

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.2018.09.017 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 t * Corresponding author. Tel.: +351 218419991. E-mail address: amd@tecnico.ulisboa.pt