PSI - Issue 6

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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 Authors. Published by Elsevier B.V. Peer-review under responsibility of the MCM 2017 organizers. XXVII International Conference “Mathematical and Computer Simulations in Mechanics of Solids and Structures”. Fundamentals of Static and Dynamic Fracture (MCM 2017) The Initiation Mechanism of Plastic Strain Localization Bands and Acoustic Anisotropy Ekaterina L. Alekseeva a , Alexad r K. Belyaev a , Aleksei I. G ishchenko a , Dmitriy E. Mansyrev a, ∗ , Vladimir A. Polyanskiy a,b , Dmitriy A. Tretyakov a , Oleg V. Shvetsov a a Peter the Great Saint-Petersburg Polytechnic University, 29, Polytechnicheskaya, St.Petersburg, 195251, Russia b Institute for Problems in Mechanical Engineering RAS, 61, Bolshoj pr. V.O., St.Petersburg, 199178, Russia Abstract The plastic strain localization in metals takes place, as a rule, at large strains and therefore it can be considered as an important in dicator of failure. Detection of plastic strain localization allows us to improve technical diagnostics. However, there is no consensus on the leading mechanism of such localization. There are two approaches: a dislocation model and a model of the dynamic instabil ity of plastic deformation associated with the descending branch of the stress-strain curve. Both models do not allow us to predict the parameters of the plastic strain localization bands, since they use characteristics that are di ffi cult to determine experimentally (for example the density of dislocations et al.). The method of acoustic anisotropy is used as a experime tal method for the precise determination of plastic strain localization zones. As the main mechanism of localization, it is proposed to consider the probability distribution of the characteristics of in ividual grains in polycrystallin material. The experimental results are described in the rticl an a new three-dimens onal model of the localization e ff ect of plastic def r tions is given, which is an important indicator of the m terial failure. c 2017 The Authors. Published by Elsevier B.V. er-review under responsibility of the CM 2017 organizers. Keywords: plastic strain localization; acoustic a iso ropy; ultrasonic dia nostics; XXVII International Conference “Mathematical and Computer Simulations in Mechanics of Solids and Structures”. Fundamentals of Static and Dynamic Fracture (MCM 2017) The Initiation echanis of Plastic Strain Localization Bands and Acoustic Anisotropy Ekaterina L. Alekseeva a , Alexader K. Belyaev a , Aleksei I. Grishchenko a , Dmitriy E. Mansyrev a, ∗ , Vladimir A. Poly nskiy a,b , Dmitr y A. Tretyakov a , Oleg V. Shvetsov a a Peter the Great Saint-Petersburg Polytechnic University, 29, Polytechnicheskaya, St.Petersburg, 195251, Russia b Institute for Problems in Mechanical Engineering RAS, 61, Bolshoj pr. V.O., St.Petersburg, 199178, Russia Abstract The plastic strain localization in metals takes place, as a rule, at large strains and therefore it can be considered as an important in dicator of failure. Detection of plastic strain localization allows us to improve technical diagnostics. However, there is no consensus on the leading mechanism of such localization. There are two approaches: a dislocation model and a model of the dynamic instabil ity of plastic deformation associated with the descending branch of the stress-strain curve. Both models do not allow us to predict the parameters of the plastic strain localization bands, since they use characteristics that are di ffi cult to determine experimentally (for example the density of dislocations et al.). The method of acoustic anisotropy is used as an experimental method for the precise determination of plastic strain localization zones. As the main mechanism of localization, it is proposed to consider the probability distribution of the characteristics of individual grains in polycrystalline material. The experimental results are described in the article and a new three-dimensional model of the localization e ff ect of plastic deformations is given, which is an important indicator of the material failure. c 2017 The Authors. Published by Elsevi r B.V. Peer-review under responsibility of the MCM 2017 organizers. Keywords: plastic strain localization; acoustic anisotropy; ultrasonic diagnostics;

© 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.

Inhomogeneity of the plastic strain field is observed in many metals. As a rule, it manifests itself in the form of the PortevinLe Chatelier e ff ect cf. Portevin (1923) and leads to the formation of localized plastic strain bands. These bands form on flat samples quasi-regular structures. An extensive literature is devoted to the explanation and modeling of the Portevin-Le Chatelier e ff ect (see the reviews Ananthakrishna (2007); Rizzi (2004)). The main mechanism is the movement or even ”jumping” of dislo- Inhomogeneity of the plastic strain field is observed in many metals. As a rule, it manifests itself in the form of the PortevinLe Chatelier e ff ect cf. Portevin (1923) and leads to the formation of localized plastic strain bands. These bands form on flat samples quasi-regular structures. An extensive literature is devoted to the explanation and modeling of the Portevin-Le Chatelier e ff ect (see the reviews Ananthakrishna (2007); Rizzi (2004)). The main mechanism is the movement or even ”jumping” of dislo-

2452-3216 © 2016 The Authors. Published by Elsevier B.V. Peer-review under responsibility of the Scientific Committee of PCF 2016. ∗ Corresponding author. Tel.: + 7-812-297-9451; fax: + 7-812-297-9451. E-mail address: 6147799@inbox.ru 2210-7843 c 2017 The Authors. Published by Elsevier B.V. Peer-revi w under responsibility of the MCM 2017 organizers. ∗ Corresponding author. Tel.: + 7-812-297-9451; fax: + 7-812-297-9451. E-mail address: 6147799@inbox.ru 2210-7843 c 2017 The Authors. Published by Elsevier B.V. Peer-review under responsibility of the MCM 2017 organizers. * 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 MCM 2017 organizers. 10.1016/j.prostr.2017.11.020