PSI - Issue 7

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ScienceDirect Available online at www.sciencedirect.com Av ilable o line at ww.sciencedire t.com ScienceDirect Structural Integrity Procedia 00 (2016) 000 – 000 Procedia Structu al Integrity 7 (2017) 242–247 Structural Integrity Procedia 00 (2017) 000–000 Available online at www.sciencedirect.com Structural Integrity Procedia 00 (2017) 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. Copyright © 2017 The Auth rs. Publis ed by Elsevier B.V. Peer-review under responsibility of the Scientific Committee of the 3rd I ternational Sympos um on Fatigue Desig and Material Defects. 3rd International Symposium on Fatigue Design and Material Defects, FDMD 2017, 19-22 September 2017, Lecco, Italy Interactions between grain size and geometrical defects in pure alumi ium in th high cycle fatig e regime Benoˆıt Bracquart a, ∗ , Charles Mareau a , Nicolas Saintier b , Franck Morel a a Arts et Me´tiers ParisTech, Campus d’Angers, LAMPA, 2 bd du Ronceray, 49035 Angers Cedex 1, France b Arts et Me´tiers ParisTech, Campus de Bordeaux-Talence, I2M, Esplanade des Arts et Me´tiers, 33405 Talence, France Abstract In this study, the influence of geometrical defects on the High Cycle Fatigue (HCF) resistance of aluminium is investigated, with emphasis on the impact of local microstructure on fatigue crack initiation. In order to meet this objective, an experimental approach, using a commercial purity polycrystalline aluminium alloy, is proposed. First, di ff erent thermomechanical treatments are applied to the aluminium alloy to obtain two homogeneous microstructures with respective mean grain sizes of 100 and 1000 µ m. Then, fatigue specimens with an artificial hemispherical surface defect of diameter 1000 µ m are subjected to fully reversed stress-controlled cyclic loading conditions. In-situ observations are carried out to monitor the crack length during fatigue tests. It is noted that, for a higher grain size, the number of cycles needed for the initiation of a 100 µ m-long surface crack is lower. A study of the influence of the defect size relative to the grain size is also conducted. Two sizes of efects are used, a the influen e of c aracteristic siz s seems to be explained by the role f cyclic plasticity in the crack initiation proc s. © 2017 The Authors. Published by Elsevier B.V. Peer-review under r sponsibility of the Scie tific Committee of the 3rd Internatio al Symposium o Fatigue Design and Material D f cts. Keywords: high-cycle fatigue, cyclic plasticity, microstructure, defect, crack initiation, aluminium 3rd International Symposium on Fatigue Design and Material Defects, FDMD 2017, 19-22 September 2017, Lecco, Italy Interactions between grain size and geometrical defects in pure aluminium in the high cycle fatigue regime Benoˆıt Bracquart a, ∗ , Charles Mareau a , Nicolas Saintier b , Franck Morel a a Arts et Me´tiers ParisTech, Campus d’Angers, LAMPA, 2 bd du Ronceray, 49035 Angers Cedex 1, France b Arts et Me´tiers ParisTech, Campus de Bordeaux-Talence, I2M, Esplanade des Arts et Me´tiers, 33405 Talence, France Abstract In this study, the influence of geometrical defects on the High Cycle Fatigue (HCF) resistance of aluminium is investigated, with mphasis on the impact of lo microstructure on fatigue crack nitiation. In order to meet this objective an experimental approach, using a commercial purity polycrystalline aluminium alloy, is proposed. First, di ff erent thermomechanical treatments are applied to the aluminium alloy to obtain two homogeneous microstructures with respective mean grain sizes of 100 and 1000 µ m. Then, fatigue specimens with an artificial hemispherical surface defect of diameter 1000 µ m are subjected to fully reversed stress-controlled cyclic loading conditions. In-situ observations are carried out to monitor the crack length during fatigue tests. It is noted that, for a higher grain size, the number of cycles needed for the initiation of a 100 µ m-long surface crack is lower. A study of the influence of the defect size relative to the grain size is also conducted. Two sizes of defects are used, and the influence of characteristic sizes seems to be explained by the role of cyclic plasticity in the crack initiation process. © 2017 The Authors. Published by Elsevier B.V. Peer-review under responsibility of the Scientific Committee of the 3rd International Symposium on Fatigue Design and Material D fects. Keywords: high-cycle fatigue, cyclic plasticity, microstructure, defect, crack initiation, aluminium

© 2016 The Authors. Published by Elsevier B.V. Peer-review under responsibility of the Scientific Committee of PCF 2016.

1. Introduction 1. Introduction

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

In metallic alloys, defects can originate from many factors [1, 2, 3, 4], and act as stress concentrators, having a detrimental influence on the High Cycle Fatigue (HCF) resistance [5]. The fatigue resistance is all the more pronounced that the defect is large. Endo et al. [6] and Luka´s et al. [7] also showed that there exists a critical defect size below which the fatigue behavior is no longer a ff ected. The dependence of this critical size regarding microstructural features remains unclear, although its knowledge is important to design fatigue-resistant structures. In metallic alloys, defects can originate from many factors [1, 2, 3, 4], and act as stress concentrators, having a detrimental influence on the High Cycle Fatigue (HCF) resistance [5]. The fatigue resistance is all the more pronounced that the defect is large. Endo et al. [6] and Luka´s et al. [7] also showed that there exists a critical defect size below which the fatigue behavior is no longer a ff ected. The dependence of this critical size regarding microstructural features remains unclear, although its knowledge is important to design fatigue-resistant structures.

* Corresponding author. Tel.: +351 218419991. E-mail address: amd@tecnico.ulisboa.pt ∗ Corresponding author. Tel.: + 33 2 41 20 73 73 E-mail address: benoit.bracquart@ensam.eu ∗ Corresponding author. Tel.: + 33 2 41 20 73 73 E-mail address: benoit.bracquart@ensam.eu

2452-3216 © 2016 The Authors. Published by Elsevier B.V. Peer-review under responsibility of the Scientific Committee of PCF 2016. 2210-7843 © 2017 The Authors. Published by Elsevier B.V. Peer-review under responsibility of the Scientific Committee of the 3rd International Symposium on Fatigue Design and Material Defects. 2210-7843 © 2017 The Authors. Published by Elsevier B.V. Peer-review under responsibility of the Scientific Committee of the 3rd International Symposium on Fatigue Design and Material Defects. 2452-3216 Copyright  2017 The Authors. Published by Elsevier B.V. Peer-review under responsibility of the Scientific Committee of the 3rd International Symposium on Fatigue Design and Material Defects. 10.1016/j.prostr.2017.11.084