PSI - Issue 7

ScienceDirect Available online at www.sciencedirect.com Av ilable o line at ww.sciencedire t.com ScienceDirect Structural Integrity Procedia 00 (2016) 000 – 000 P o edi Structural Integr ty 7 (2017) 27–32 Structural Integrity Procedia 00 (2017) 000–000 Available online at www.sciencedirect.com Structural Integrity Procedia 00 (2017) 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. ∗ Jean-Yves Bu ffi ere MATEIS Laboratory INSA LYON. E-mail address: jean-yves.bu ffi ere@insa-lyon.fr 2210-7843 c 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. In structural components submitted to cyclic loads, a large part of the fatigue life can be spent in initiating and / or growing cracks which ave a strong three dimensional character i.e. which behavior at the surface can di ff er with that occurring in the bulk (Schijve (2009)). For materials with large microstrutural heterogeneities (defects) such as pores or large second phase particles, early studies have shown that the formation of a fatigue crack from a subsurface defect is a three dimensional process which is di ffi cult to image form 2D observations (Clement et al. (1984), Nadot et al. (1997)). For low load levels ( e.g. for ∆ K values close to ∆ K th ) the material microstructure (grains, second phase particles, fibers, sub surface defects) can account in a large part for those 3D e ff ects, but other experimental factors can also play a role such as the sub surface evolution of the stress state (change from plane stress to plane strain, or change in the stress direction and magnitude in the case or torsion or bending), the change in environment (from air to vacuum), the presence of residual stresses or grain size gradients due to processing etc. Therefore, ideally, a thorough understanding of fatigue mechanisms requires 3D observations at the micro scale ( ∼ 1 µ m spatial resolution). Experimental methods for the characterization of fatigue cracks can be classified in two classes corresponding to direct and indirect methods. Direct imaging is carried out on 2D sections at the sample surface with a spatial resolution ∗ Jean-Yves Bu ffi ere MATEIS Laboratory INSA LYON. E-mail address: jean-yves.bu ffi ere@insa-lyon.fr 2210-7843 c 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. 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 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. 3rd International Symposium on Fatigue Design and Material Defects, FDMD 2017, 19-22 September 2017, Lecco, Italy Fatigue Crack Initiation And Propagation From Defects In Metals: Is 3D Ch racterization Important? Jean-Yves Bu ffi ere a, ∗ a INSA Lyon, 20 Avenue A.Einstein, Villeurbanne 69621 France Abstract This paper aims at illustrating the physical information that can be extracted from 3D tomographic images of fatigue cracks gr wing from defects. After highlighting the current limits of the method, examples of application are given for various metallic materials, a comparison of the merits of n tur l v.s. artificial defects is given with examples of how the 3D data can be used for modeling. c 2017 The Authors. Published by Elsevier B.V. Peer-review under r sponsibility of the Scientific Committee of the 3rd International Symposium on Fatigue Design and Material Defects. Keywords: Synchrotron; Tomography: Defects; Crack; In Situ; Fatigue. 1. Introduction In structural components submitted to cyclic loads, a large part of the fatigue life can be spent in initiating and / or growing cracks which have a strong three dimensional character i.e. which behavior at the surface can di ff er with that occurring in the bulk (Schijve (2009)). For materials with large microstrutural heterogeneities (defects) such as pores or large second phase particles, early studies have shown that the formation of a fatigue crack from a subsurface defect is a three dimensional process which is di ffi cult to image form 2D observations (Clement et al. (1984), Nadot et al. (1997)). For low l ad levels ( e.g. for ∆ K values close to ∆ K th ) the material microstructure (grains, second phase particles, fibers, sub surface defects) can account in a large part for those 3D e ff ects, but other experimental factors can also play a role such as the sub surface evolution of the stress state (change from plane stress to plane strain, or change in the stress direction and magnitude in the case or torsion or bending), the change in environment (from air to vacuum), the presence of residual stresses or grain size gradients due to processing etc. Therefore, ideally, a thorough understanding of fatigue mechanisms requires 3D observations at the micro scale ( ∼ 1 µ m spatial resolution). Experimental methods for the characterization of fatigue cracks can be classified in two classes corresponding to direct and indirect methods. Direct imaging is carried out on 2D sections at the sample surface with a spatial resolution 3rd International Symposium on Fatigue Design and Material Defects, FDMD 2017, 19-22 September 2017, Lecco, Italy Fatigue Crack Initiation And Propagation From Defects In Metals: Is 3D Characterization Important? Jean-Yve Bu ffi ere a, ∗ a INSA Lyon, 20 Avenue A.Einstein, Villeurbanne 69621 France Abstract This paper aims at illustrating the physical information that can be extracted from 3D tomographic images of fatigue cracks growing from defects. After highlighting the current limits of the method, examples of application are given for various metallic materials, a comparison of the erits of natural v.s. artificial defects is given with examples of how the 3D data can be used for modeling. c 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: Synchrotron; Tomography: Defects; Crack; In Situ; Fatigue. 1. Introduction © 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 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.2017.11.056