PSI - Issue 3

ScienceDirect Available online at www.sciencedirect.com Av ilable o line at ww.sciencedire t.com ScienceDirect Structural Integrity Procedia 00 (2016) 000 – 000 Procedia Structu al Integrity 3 (2017) 291–298 Available online at www.sciencedirect.com ScienceDire t Structural Integrity Procedia 00 (2017) 000–000 Available online at www.sciencedirect.com ScienceDirect Structural Integrity Procedia 00 (2017) 000–000

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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 Elsevi r B.V. This is an open access article under the CC BY-NC-ND license (http://cr ativecommons.org/licenses/by-nc-nd/4.0/). Peer-review under responsibility f the Scien ific Committee of IGF Ex-Co. XXIV Italian Group of Fracture Conference, 1-3 March 2017, Urbino, Italy Fatigue crack propagation in Ductile Cast Irons: an Artificial Neural Networks based model Laura D’Agostino a , Alberto De Santis b , Vittorio Di Cocco a , Daniela Iacoviello b *, Francesco Iacoviello a a Università di Cassino e del Lazio meridionale, DICeM, via G. Di Biasio 43, 03043, Cassino (FR) Italy b Università di Roma “La Sapienza”, DIAG, via Ariosto 25, 00185 Rome, Italy Abstract All the available “Paris-like” models (analytical relationships between da/dN, crack growth rates, and  K, stress intensity factor amplitude) are not able to take into account the possible influence of all the parameters that influence the fatigue crack propagation process. Among them, the stress ratio R (e.g., K min /K max ) is one of the most investigated and, although in the last decades the influence of R on the different propagation mechanisms has been widely investigated (e.g., crack closure effect), this parameter is often considered as an independent variable in the “Paris-like” models. A different approach can be followed using the Artificial Neural Networks that are able to consider all the possible parameters, with the condition of a satisfactory training stage. In this work, an artificial Neural Networks based model is optimized considering the influence of the stress ratio on the fatigue crack propagation in a ferritic-pearlitic Ductile Cast Iron. © 2017 The Authors. Published by Elsevier B.V. Peer-review under responsibility of the Scientific Committee of IGF Ex-Co. Keywords: Fatigue crack propagation; Artificial Neuran Networs; Ductile Cast Irons. 1. Introductio Up to the first half of the last century, only malleable irons were able to partially offer a combination of grey iron castability and steel mechanical properties (first of all, toughness). These cast irons were obtained as a result of XXIV Italian Group of Fracture Conference, 1-3 March 2017, Urbino, Italy Fatigue crack propagation in Ductile Cast Irons: an Artificial Neural Networks based model Laura D’Agostino a , Alberto De Santis b , Vittorio Di Cocco a , Daniela Iacoviello b *, Francesco Iac v ello a a Università di Cassino e del Lazio meridionale, DICeM, via G. Di Biasio 43, 03043, Cassino (FR) Italy b Università di Rom “La Sapienza”, DIAG, via Ariosto 25, 00185 Rome, Italy Abstract All the available “Paris-like” models (analytical relationships between da/dN, crack growth rates, and  K, stress intensity factor amplitude) are not able to take into account the p ssible influence of all the parameters that influence the fatigue crack pro agation process. Among th m, the stress ratio R (e.g., K min /K max ) is one of the most investigated and, alt ough in the last decades the influ nce of R on t e different propagation mechanisms has been widely investigated (e.g., crack closure effect), this parameter is often considered as an ind pendent v riable in the “Paris-lik ” models. A different approa h an be follow d using the Artificial Neural Networks that are able to consider all the possible para eters, with the condition of a satisfact ry traini stage. In this work, an artificial Neural Networks bas d mod l is optimized considering the influence of the stress ratio on the fatigue crack pr pag tion in a ferritic-pearlitic Ductile Cast Iron. © 2017 The Authors. Published by Elsevier B.V. Peer-review under responsibility of the Scientific Committee of IGF Ex-Co. Keywords: Fatigue crack propagation; Artificial Neuran Networs; Ductile Cast Irons. 1. Introduction Up to the first half of the last century, only malleable irons were able to partially offer a combination of grey iron castability and steel mec anical properties (first of a l, t ughn ss). These cast irons were btai ed as a result f © 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.: +39-677274061 E-mail address: iacoviello@dis.uniroma1.it * Corresponding author. Tel.: +39-677274061 E-mail address: iacoviello@dis.uniroma1.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.2017.04.048