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) 97–103 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 Th Authors. Published by Elsevier Ltd. This is an open access article under the CC BY-NC-ND l cense (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 Tsallis entropy modeling of Pressure Stimulated Currents when cement-based materials are subjected to abrupt repetitive b nding loadings A. Kyriazopoulos, I. Christakis, I. Stavrakas* Electronic Devices and Materials Laboratory, University of West Attica, Athens, 12210, Greece Abstract Pressure Stimulated Currents (PSCs) are emitted while brittle materials of high electrical resistivity are subjected to mechanical loading. The PSCs are related to the generation of cracks and the consequent evolution of cracks’ network in the bulk of the specimen. In the experimental protocol described here cement-mortar beams of rectangular cross-section were subjected to Three-Point Bending (3PB) repetitive loading/unloading loops. The qualitative and quantitative characteristics of the recorded PSCs match corresponding recordings previously published. More specifically, during the load increase a spike-like PSC emission was recorded followed by a relaxation of th PSC, after reaching its final value. The relaxation process of th PSC was then studied n terms of non- xtensive statistical physic (NESP) based on Tsallis ntropy equation. The b havior of the Tsallis ara met r was studied in relaxat on PSCs in rder to inv st ga its potential use as an index for monitoring the crack v lution proc ss with a potential use in non- structive laboratory te ting of cement-based specimens of unknown internal damage level. This analysis of the experimental data indicated that the value of the entropic index q exhibits a charact ristic d crease attaining the critical value of 1.25 while reaching the ultimate strength of the specimen, and thus could be used as a forerunner of the expected failure. © 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 abor e i t e e This is an open access a cle und t © 2016 The Authors. Published by Elsevier B.V. Peer-review under responsibility of the Scientific Committee of PCF 2016. Keywords: Cement mortar bending; Pressure Stimulated Currents; electrical signal emissions; Tsallis entropy Keywords: Cement mortar bending; Pressure St

Keywords: High Pressure Turbine Blade; Creep; Finite Element Method; 3D Model; Simulation.

* Corresponding author: Tel.: +30 210 5385391 E-mail address : ilias@ee.teiath.gr Received: April 14, 2018; Received in revised form: July 13, 2018; Accepted: July 18, 2018 *

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.2018.09.015 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 st * Corresponding author. Tel.: +351 218419991. E-mail address: amd@tecnico.ulisboa.pt