PSI - Issue 3

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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. 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 IGF Ex-Co. XXIV Italian Group of Fracture Conference, 1-3 March 2017, Urbino, Italy Duplex tainl ss steels “475° embrittlement”: influence of the chemical composition on the fatigue crack propagation Vittorio Di Cocco a *, Francesco Iacoviello a , Gloria Ischia b a Università di Cassino e del Lazio Meridionale, DICeM, via G. Di Biasio 43, 03043, Cassino (FR), Italy b Università di Trento, DII, via Sommarive, 9, 38123 Povo, Trento, Italy Abstract Duplex stainless steels (DSSs) are prone to age hardening and embrittle over a wide temperature range depending on their chemical composition. This is mainly due to precipitation phenomena that may occur inside ferrite grains and at ferrite-austenite grain boundaries. The aim of this work is the analysis of chemical composition influence on fatigue crack propagation resistance of “475°C embrittled” duplex stainless steels. Fatigue crack propagation resistance of 21 Cr 1 Ni, 22 Cr 5 Ni and 25 Cr 7 Ni duplex stainless steels was investigated considering both as received and 475°C embrittled conditions (1000h). Microstructural analyses wer perfo med using a transmissio electr n microscope (TEM). Conce trations of th main elements, but carbon, were evaluated using a standardless analysis program. © 2017 The Authors. Published by Elsevier B.V. Peer-review under responsibility of the Scientific Committee of IGF Ex-Co. Keywords: 475°C embrittlement; TEM analysis; Fatigue crack propagation. 1. Introduction Duplex stainless steels are successfully used in chemical, petrochemical, nuclear, fertilizer and food industries. Their good mechanical properties and their excellent c rrosion resistance in many environments and operating conditions, like chloride induced stress corrosion, mainly depend on their chemical composition and on the ferrite and austenite volume fractions, Lacombe (1990), Gunn (1997), Iacoviello (2005). Considering the pitting index, or pitting resistant equivalent (e.g. PRE= %Cr + 3.3 (%Mo + 0.5%W) + 16 %N), these steels can be classified considering three classes at least: XXIV Italian Group of Fracture Conference, 1-3 March 2017, Urbino, Italy Duplex stainless steels “475°C embrittlement”: influence of the chemical composition on the fatigue crack propagation Vittorio Di Cocco a *, Francesco Iacoviello a , Gloria Ischia b a Università di Cassino e del Lazio Meridionale, DICeM, via G. Di Biasio 43, 03043, Cassino (FR), Italy b Università di Trento, DII, via Sommarive, 9, 38123 Povo, Trento, Italy Abstract Duplex stainless steels (DSSs) are prone to age hardening and embrittle over a wide temperature range depending on their chemical composition. This is m inly du to precipitatio phenom na that may occur insid ferrite grains and at ferr te-austenite grain boundaries. The aim of this work is the analysis of chemical composition infl ence on atigue crack prop gation resi ta c of “475°C embrittled” duplex stainless teels. Fatigue crack propagation resista ce of 21 Cr 1 Ni, 22 Cr 5 Ni nd 25 Cr 7 Ni duplex stainless s e ls was invest gated considerin both as received and 475°C embrittled conditions (1000h). Microstructural analyse wer performed using a transmission electr n mic oscop (TEM). Concent a ions f the main elements, but carbon, were evaluat d using a standardl ss alysis pro ram. © 2017 The Authors. Publish by Elsevier B.V. Peer-review under espons bility of the Scientific Committee of IGF Ex-Co. Keywords: 475°C embrittlement; TEM analysis; Fatigue rack propagation. 1. Introduction Duplex stainless steels are successfully used in chemical, petrochemical, nuclear, fertilizer and food industries. Their good mechanical prop rties and their xcellent corrosion resistance i many nvironments an operat ng conditions, lik chloride induced str ss corrosion, ainly depend on their chemic l composition and on the ferrite and austenite volume fractions, Lacombe (1990), Gun (1997), Iacoviello (2005). Considering the pitti g index, or pitting r stant equivalent (e.g. PRE= %Cr + 3.3 (%Mo + 0.5%W) + 16 %N), thes steels can be classified conside ing hree classes at least: © 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.: +39.67762994334. E-mail address: v.dicocco@unicas.it * Corresponding author. Tel.: +39.67762994334. E-mail address: v.dicocco@unicas.it

* Corresponding author. Tel.: +351 218419991. E-mail address: amd@tecnico.ulisboa.pt 2452-3216 © 2017 The Authors. Published by Elsevier B.V. Peer-review under responsibility of the Scientific Committee of IGF Ex-Co. 2452-3216 © 2017 The Authors. Published by Elsevier B.V. Peer-review under responsibility of the Scientific Committee of IGF Ex-Co.

2452-3216 © 2016 The Authors. Published by Elsevier B.V. Peer-review under responsibility of the Scientific Committee of PCF 2016. Copyright © 2017 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 IGF Ex-Co. 10.1016/j.prostr.2017.04.051