PSI - Issue 2_B

ScienceDirect Available online at www.sciencedirect.com Av ilable o line at ww.sciencedire t.com cienceDirect Structural Integrity Procedia 00 (2016) 000 – 000 Procedia Struc ural Integrity 2 (2016) 2123–2131 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 Identification of local phenomena of plasticity in concrete under compression test Risitano A a , D’Aveni b A a ., Fargion G a ., Clienti C a . a Department of Industrial Engineering, b Department of Civil Engineering and Architecture In this paper are specifically derived parameters useful to estimate the fatigue behaviour of concrete subject to uniaxial compression. For this, methodologies and experience already adopted in the study of fatigue steel and composite materials are used. These parameters are obtained by detecting the surface temperature of the specimen in the traditional static compression tests. In this way, the beginning of the crisis of the concrete for fatigue stress is linked to the loss of linearity of the temperature test time curve ( Δ T- t) and correlated to stress-test time curve ( σ - t) of the tested cubic concrete specimens. In fact, the thermal analysis performed on the cubic specimen surface extended to the whole test time, shows interesting data on the crack beginning and on the subsequent evolution that after a certain number of loading cycles could determine the complete material failure. The slope variation in the interpolating curve temperature-test time allows to identify the critical points of the start fracture. This suggests a methodology to apply to civil infrastructures to evaluate in-situ, during the approval phase or during the working, critical situations. In this paper we propose a method to estimate the value of the "stress limit" (fatigue limit) of concrete material by means of an easy static uniaxial compression test according to an energetic method already proposed by Risitano. © 2016 The Authors. Published by Elsevier B.V. Peer-review under responsibility of the Scientific Committee of ECF21. Copyright © 2016 The Authors. Published by El evier B.V. This is an open access le under the CC BY-NC-ND lic nse (http://creativecommons.org/licenses/by-n -nd/4.0/). Peer-review under responsibility of the Scientific Committee of ECF21. Abstract

© 2016 The Authors. Published by Elsevier B.V. Peer-review under responsibility of the Scientific Committee of PCF 2016. Keywords: crack; stress limit ; specimen; temperature-test; loading cycles.

Keywords: High Pressure Turbine Blade; Creep; Finite Element Method; 3D Model; Simulation. 1. Introduction In many concrete civil infrastructures, such as large bridges, viaducts and/or paving of airport runways, it is possible to verify concrete fatigue failures. They, in general, can be investigated with the same criteria used for mechanical structures.

* Corresponding author. Tel.: +351 218419991. E-mail address: amd@tecnico.ulisboa.pt 2452-3216 © 2016 The Authors. Published by Elsevier B.V. Peer-review under 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 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.2016.06.266