PSI - Issue 2_B

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 Struc ural Integrity 2 (2016) 2913–292 Available online at www.sciencedirect.com ScienceDirect Structural Integrity Procedia 00 (2016) 000–000 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 Stress-strain behaviour of asphalt concrete in compression Lee Leon*, Raymond Charles, Nicola Simpson University of the West Indies, St. Augustine, Trinidad & Tobago Abstract This paper presents an evaluation of the failure mode of asphalt concrete and describes the stress-strain curve that governs asphalt concrete beyond the limit of elasticity in the ascending branch. The relationship of stress-strain is identical to that of cement concrete in compression. A general form of the behavioural curve is proposed to represent the elastic and plastic – damage of asphalt concrete. The nonlinear beh viour of asphalt concrete beyond the li ear elastic lim t swelling is visible to the naked eye. These parameters that define this form are physically significant and are determined experimentally. The parameters of the stress strain curve are fundamental characteristics of a solid subjected to short term loading. The experiments used short term static compression loading on cylindrical asphalt concrete specimens, differing in mix types (Dense graded, Stone Matrix), air voids content, density, specimen size and temperature. There were significant changes in the peak stress and strains between the asphalt concrete mix types. Different strengths are attainable between asphalt concrete types as well as the properties of the mix constituents. The proposed equations fit a wide range of testing conditions and asphalt concrete type for both the ascending and descending branches of the stress-strain diagram in compression. The investigation derives parameters (yield stress and elastic modulus) for different asphalt concrete mix types which can be used in FE programs such as Abaqus that uses the elastic as well as plastic data to model the behaviour of different mix types of asphalt concrete material used in a pavement structure. © 2016 The Authors. Published by Elsevier B.V. Peer-review under responsibility of the Scientific Committee of ECF21. Keywords: elasticity; plastic; asphalt concrete; elastic modulus; compression; stress strain . 1. Introduction Asphalt concrete, hereafter referred to as AC, is a composite material made up of different grades of aggregates bound together using asphalt/bitumen. The combination of these components and their separate properties contribute to the material properties of AC which dictates its performance during service. AC has many uses such as paving 21st European Conference on Fracture, ECF21, 20-24 June 2016, Catania, Italy Stress-strain behaviour of asphalt concrete in compression Lee Leon*, Raymond Charles, Nicola Simpson University f the West Indies, St. Augustine, Trinidad & Tobago Abstract This paper presents an evaluation of the failure mode of asphalt concrete and describes the stress-strain curve that governs asphalt concrete beyond he limit of elasticity in the ascending branch. The relationship of str ss-strain is identical to that of cemen in c mpression. A g neral form of the behavioural urve is proposed to represent the ela t c and plastic – damage of asphalt co crete. The nonlinear behaviour asphalt concrete beyond the linear elastic limit sw lling is visible to the n ked ye. These paramet rs t at define this form are physically significant and are determine exp rimentally. The parame ers of the str ss strain cu ve ar fundamental characteristics of a solid subjected to short loading. Th experiments used short term static compression loadi g on cylindric l asphalt c ncrete specimens, differing in ix types (Dens graded, Ston Matrix), air voids ntent, de sity, specimen s ze and temperature. Th re were significant cha ges in the peak str ss nd strains between the asphalt cre e mix types. Different strengths are attainable betwee asphalt concrete ty es a well as the properti s of the mix stituents. The proposed quatio s fit a wide ra ge of t sting conditions a d asphalt concret type for both the a cending and descendi g branches of the stress-strain diagram in compression. The investigation derives parameters (yield stress and elastic modulus) for different asphalt concrete mix types which can be used in FE pro rams such a Ab qus that uses the elastic as well as plastic data to model the behaviour of different mix types of asphalt concrete material used in pavement structure. © 2016 The Authors. Published by Elsevier B.V. Peer-review under espons bility of the Scientific Committee of ECF21. Keywords: elasticity; plastic; asphalt concrete; elastic modulus; compression; stress strain . 1. Introduction Asphalt concr te, hereafter referr d to as A , is a composite material made up of different grades of aggregates bound together using asphalt/bitumen. The combination of thes components and their sepa ate p op rties contribute t the material properties of AC which dictates ts performance during service. AC has m ny uses such as paving Copyright © 2016 The Auth rs. Published by Elsevier B.V. This is an open access article u der 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. © 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.: +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 ECF21. * Corresponding author. Tel.: +1-868-719-6590; fax: +1-868-645-7691. E-mail address: lee.leon@sta.uwi.edu * Corresponding author. Tel.: +1-868-719-6590; fax: +1-868-645-7691. E-mail address: lee.leon@sta.uwi.edu

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.2016.06.364