PSI - Issue 2_A

ScienceDirect Available online at www.sciencedirect.com Av ilable online at ww.sciencedire t.com Sci ceDirect Structural Integrity Procedia 00 (2016) 000 – 000 Procedia Struc ural Integrity 2 (2016) 2206–2213 Sci nceDirect Structural Integrity Procedia 00 (2016) 000–000 ScienceDirect Structural Integrity Procedia 00 (2016) 000–000 Available online at www.sciencedirect.com Available online at www.sciencedirect.com

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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 A study on evaluation of ductile crack initi tion using strain hardening exponent for steels Takehisa Yamada a, *, Yoichi Yamashita a , Sohei Kanna a a Research Laboratory, IHI Corporation, 1, Shin-nakahara-cho, Isogo-ku, Yokohama, 235-8501, Japan Evaluation method of ductile crack initiation limit without depending on materials was investigated. Ductile crack initiation behaviors were experimentally d analytically comprehended using aluminum alloy as non-ferrous metal in addition to tw different steels. It was found that their limit characteristics of ductile crack initiation for materials used were different in the case of using a conventional method based on stress triaxiality factor and equivalent plastic strain. It is considered that from cross section observations, ductile crack initiation for steels is caused by shear fracture between grown voids at the center of specimen. Therefore, Mohr-Coulomb fracture criterion, which is related to normal stress and shear stress, was applied to the evaluation of steels. As a result, it was found that strain hardening exponent of the materials could be a new parameter. Using strain hardening exponent in addition to stress triaxiality factor and equivalent plastic strain, ductile crack initiation li it of different steels whose fracture mechanisms are similar, can be evaluated with a master curve. © 2016 The Authors. Published by Elsevier B.V. Peer-review under responsibility of the Scientific Committee of ECF21. Keywords: Dutile crack initiation; Stress triaxiality factor; Equivalent plastic strain; Strain hardening exponent 1. Introduction Ductile fract re limit of metals has b en evaluated using stress triaxiality factor and equivalent strain by Johnson and Cook (1985). It has been found that ductile crack initiation is caused by the growth and coalescence of micro voids generated in the materials by Otsuka et al. (1981). The limit characteristics of ductile crack initiation are obtained from tensile tests of notched specimens and the finite element analyses by Enami (2005). Because the characteristics are dependent on materials, fracture tests using materials evaluated has to be conducted in each case. 21st European Conference on Fracture, ECF21, 20-24 June 2016, Catania, Italy A study on evaluation of ductile crack initiation using strain hardening exponent for steels Takehisa Yamada a, *, Yoichi Yamashita a , Sohei Kanna a a Research Laboratory, IHI Corporation, 1, Shin-nakahara-cho, Isogo-ku, Yokohama, 235-8501, Japan Abstract Evaluation method of ductile crack initiation limit without depending on materials was investigated. Ductile crack initiation behaviors were experimen ally and a alytically compre ended using aluminum al oy non-ferrous metal n additio o wo different ste ls. It was found that their limit chara teristics of ductile cr ck initiation for materials used w re d fferent n the case of using a conventional method based on stress triaxiality actor and equivalent plastic strain. It i considered that from cro s sectio observations, ductil crack initiation for teels s caused by shear fracture between g own voids at the c nter of specimen. Therefore, Mohr-Coulomb fracture criteri , which is rel ted to norm l stress and sh ar st ess, was applied to th evaluation of ste ls. As a result, it was found that strain hardening expon nt f the material could be a new par meter. Using strain harde ing exponent in addi ion to tress triaxiality facto a d equivalent plas ic str in, ductile crack i itiation limit of different steels whose fracture mechan sms are simila , can be evaluated with a mas er curve. © 2016 The Authors. Published by Els vier B.V. Peer-review under espons bility of the Scientific Committee of ECF21. Keywords: Dutile crack initiation; Stress triaxiality factor; Equivalent plastic strain; Strain hardening exponent 1. Introduction Ductile fracture limit of metals has been evaluated using stress triaxiality factor and equivalent strain by Johnson and Cook (1985). It has been found that ductile crack initiation is c used by the growth and coalesce ce of micro voids generated in t e mat rials by Otsuka et al. (1981). The limit characteristics of ductile crack initiation a e obtained from te sile tests of notched pecimens and the finite element naly es by Enami (2005). Because th characteristics are dependent o mat rials, fracture tests using mat rials ev lu ted has to be conducted in each case. Copyright © 2016 The Authors. Published by Elsevier B.V. This is an open access article under the CC BY-NC-ND license (http:// r ativecommons. rg/licenses/by-nc-nd/4.0/). Peer-review under responsibility of the Scientific Co mittee 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. Abstract

* 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 r sponsibility of the Scientific Committee of ECF21. * Corresponding author. Tel.: +81-45-759-2864; fax: +81-45-759-2210. E-mail address: takehisa_yamada@ihi.co.jp * Corresponding author. Tel.: +81-45-759-2864; fax: +81-45-759-2210. E-mail address: takehisa_yamada@ihi.co.jp

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.2016.06.276