PSI - Issue 2_B

ScienceDirect Available online at www.sciencedirect.com Av ilable o line at ww.sciencedire t.com Sci nceDirect Structural Integrity Procedia 00 (2016) 000 – 000 Procedia Struc ural Integrity 2 (2016) 321 –3217 Structural Integrity Procedia 00 (2016) 000–000 Available online at www.sciencedirect.com Structural Integrity Procedia 00 (2016) 000–000 Available online at www.sciencedirect.com Structural Integrity Procedia 00 (2016) 000–000 Available online at www.sciencedirect.com

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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.2016.06.400 ∗ Corresponding author. Tel.: + 33 5 56 84 53 61. ; fax: + 33 5 56 84 53 66. E-mail address: nicolas.saintier@ensam.eu 2452-3216 c 2016 The Authors. Published by Elsevier B.V. Peer-review under responsibility of the Scientific Committee of ECF21. Fatigue remains today one of the essential causes of mechanical components and structures failure in service under cyclic loading. It has been well understood for decades that two main steps characterize the fatigue failure which are the crack initiation and propagation. In high cycle fatigue (HCF) regime, a large part of life is spent in the crack initiation phase (more than 90 % of the total life, see Klesnil and Lukas (1992)). The fatigue life of the material depends primarily on this crack initiation phase (mainly stage I). In this regime, crack initiation is controlled by the formation and development of persistent slip bands (PSB) at the surface for pure metallic materials without internal defects. ∗ Corresponding author. Tel.: + 33 5 56 84 53 61. ; fax: + 33 5 56 84 53 66. E-mail address: nic las.saintier@ nsam.eu 2452-3216 c 2016 The Authors. Published by Elsevier B.V. e r-review under responsibility of the Scientific Committee of ECF21. Fatigue remains today one of the essential causes of mechanical components and structures failure in service under cyclic loading. It has been well understood for de ades that two main steps characterize the fatigu failure whi h are the crack initiation and propagation. In high cycl fatigue (HCF) regime, a large part of life is spent in the crack initiation phase (m re than 90 % of the tot l life, see Klesnil and Lukas (1992)). The fatigue life of the material depends primarily on this crack initiation phase (mainly st ge I). In this regime, crack initiation is contr lled by the formation and development of persistent slip bands (PSB) at the surface for pure metallic materials without internal defects. ∗ Corresponding author. Tel.: + 33 5 56 84 53 61. ; fax: + 33 5 56 84 53 66. E-mail address: nicolas.saintier@ensam.eu 2452-3216 c 2016 The Authors. Published by Elsevier B.V. Peer-review under responsibility of the Scientific Committee of ECF21. 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 Microstructure-based study of the crack initiation mechanisms in pure copper under high cycle multiaxial fatigue loading conditions Komlan Agbessi a , Nicolas Saintier a, ∗ , Thierry Palin-Luc a a Arts et Metiers ParisTech, I2M, CNRS, Esplanade des Arts et Metiers, 33405 Talence Cedex, France Abstract This paper aims to contribute in understanding the fatigue crack initiation mechanisms in metallic materials under high cycle multiaxial fatigue loadings. It addresses proportional and non-proportional multiaxial lo ding conditions with the analysis and observation of the cyclic plasticity development (mainly persistent slip band) until crack initiation (especially short cracks) on a pure oxygen-fr e high conductivity (OFHC) polycristalline coppe . Observation and nalysis techniques are based mainly on optical microscopy and scanning electron microscopy (SEM). It has been observed that the plastic slip multiplicity in grains seems more important for multiaxial loadings at a stress level corresponding to the same median fatigue strength at 10 6 cycles of the material. A multiaxial loading induces an additional multiplicity of the plastic slip in grains compared to uniaxial loading condition. For all the loading conditions investigated, although most of the grains exhibits single slip activated, analysis of the preferential crack initiation sites and modes show a higher probability of intragranular microcrack initiation in the multiple slip grains (with more than two slip systems activated). Most multiple slip grains and higher probability of crack initiation in these grains were observed especially for non-proportional multiaxial loadings. Finally, the e ff ects of the biaxiality ratio and the phase shift on the fatigue crack initiation was highlighted. c 2016 The Authors. Published by Elsevier B.V. Peer-review under responsibility of the Scientific Committee of ECF21. Keywords: high cycle multiaxial fatigue; persistent slip band; cyclic plasticity; multiple slip; intragranular crack initiation Fatigue remains today one of the essential causes of mechanical components and structures failure in service under cyclic loading. It has been well understood for decades that two main steps characterize the fatigue failure which are the crack initiation and propagation. In high cycle fatigue (HCF) regime, a large part of life is spent in the crack initiation phase (more than 90 % of the total life, see Klesnil and Lukas (1992)). The fatigue life of the material depends primarily on this crack initiation phase (mainly stage I). In this regime, crack initiation is controlled by the formation and development of persistent slip bands (PSB) at the surface for pure metallic materials without internal defects. 21st European Conference on Fracture, ECF21, 20-24 June 2016, Catani , Italy Microstructure-based study of the crack initiation mechanisms in pure copper under high cycle multiaxial fatigue loading conditions Komlan Agbessi a , Nicolas Saintier a, ∗ , Thierry Palin-Luc a a Arts et Metiers ParisTech, I2M, CNRS, Esplanade des Arts et Metiers, 33405 Talence Cedex, France Abs ract This paper aims to contribute in understanding the fatigue crack initiation mechanisms in metallic materials under high cycle multiaxial fatigue loadings. It addresses proportional and non-proportional multiaxial loading conditions with the analysis and observation of the cyclic plasticity development (mainly persistent slip band) unt l crack initiation (espe ially hort cracks) on a pure oxygen-free high conductivity (OFHC) polycristalline copper. Observation and analysis techniques are based mainly on optical microscopy and scanning electron microscopy (SEM). It has been observed that the plastic slip multiplicity in grains seems more important for multiaxial loadings at a stress level corresponding to the same median fatigue strength at 10 6 cycles of the material. A multiaxial loading induces an additional multiplicity of the plastic slip in grains compared to uniaxial loading condition. For all the loading conditions investigated, although most of the grains exhibits single slip activated, analysis of the preferential crack initiation sites and modes show a higher probability of intragranular microcrack initiation in the multiple slip grains (with more than two slip systems activated). Most multiple slip grains and higher probability of crack initiation in these grains were observed especially for non-proportional multiaxial loadings. Finally, the e ff ects of the biaxiality ratio and the phase shift on the fatigue crack initiation was highlighted. c 2016 The Authors. Published by Elsevier B.V. Peer-review under responsibility of the Scientific Committee of ECF21. Keywords: high cycle multiaxial fatigue; persistent slip band; cyclic plasticity; multiple slip; intragranular crack initiation 1. Introduction 21st European Conference on Fracture, ECF21, 20-24 June 2016, Catania, Italy Microstructure-based study of the crack initiation mechanisms in pure copper under high cycle multiaxial fatig e loading conditions Komlan Agbessi a , icolas Saintier a, ∗ , Thierry Palin-Luc a a Arts et Metiers ParisTech, I2M, CNRS, Esplanade des Arts et Metiers, 33405 Talence Cedex, France Abstract This paper aims to contribute in u dersta ding the fatigue cra k initiation mechanisms in metallic materials under high cycle multiaxial fatigue loadings. It addresses proportional and non-proportional multiaxial loading conditions with the analysis and observation of the cyclic plasticity development (mainly persistent slip band) until crack initiation (especially short cracks) on a pure oxygen-free high conductivity (OFHC) polycristalline copper. Observation and analysis techniques are based mainly on optical microscopy and scanning electron microscopy (SEM). It has been observed that the plastic slip multiplicity in grains seems more important for multiaxial loadings at a stress level corresponding to the same median fatigue strength at 10 6 cycles of the material. A multiaxial loading induces an additional multiplicity of the plastic slip in grains compared to uniaxial loading condition. For all the lo ding conditions investigated, although most of the grains exhibits single slip activated, analysis of the preferential crack initiation sites and modes show a higher probability of intragranular microcrack initiation in the multiple slip grains (with more than two slip systems activated). Most multiple slip grains a d higher pro ability of crack initiation in these rains were observed especially for non-proportional multiaxial loading . Finally, the e ff ects of t e biaxiality ratio and the phase shift on the fatigue crack initiation was highlig ted. c 2016 The Authors. Published by Elsevier B.V. Peer-review under responsibility of the Scientific Committee of ECF21. Keywords: high cycle multiaxial fatigue; persistent slip band; cyclic plasticity; multiple slip; intragranular crack initiation 1. Introduction 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/). er-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. 1. Introduction Keywords: High Pressure Turbine Blade; Creep; Finite Element Method; 3D Model; Simulation. * Corresponding author. Tel.: +351 218419991. E-mail address: amd@tecnico.ulisboa.pt