PSI - Issue 3

ScienceDirect Available online at www.sciencedirect.com Av ilable o line at ww.sciencedire t.com cienceDirect Structural Integrity Procedia 00 (2016) 000 – 000 Procedia Structu al Integrity 3 (2017) 553–561 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 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. XXIV Italian Group of Fracture Conference, 1-3 March 2017, Urbino, Italy Failure Investigation: in Flight Loss of a Main Landing Gear Door of a Transport Aircraft. G. Zucca, V. di Francesco, M.Bernabei, F. De Paolis* Italian Air Force, Flight Test Centre, Chemistry De artment, Milit ry Airport M. De Bernardi, via Pratica di Mare, 00040 Pomezia (RM), Italy Abstract An executive transport military aircraft experienced the loss of the left main landing gear door during a standard flight. In the aftermath of this serious occurrence, at the Chemistry Department of the Flight Test Center of the Italian Air Force (IAF), a technical investigation started to identify the root causes of the failure and to prevent other similar incidents. The investigation was carried out jointly with the representative of the manufacturing company and was focused on the fracture surfaces of the hinges connecting the door to the fuselage. This paper shows the results obtained by fractographic (optical and electronic microscopy), metallographic, chemical analysis and numerical simulation: the root cause of the cracks was a phenomenon of pitting corrosion mainly located on the door back hinge a d du to a local loss of coating. This made possible a fatigue fracture mechanism under nor al operative cyclic loads. © 2017 The Authors. Published by Elsevier B.V. Peer-review under responsibility of the Scientific Committee of IGF Ex-Co. Keywords: Transport aircraft, Fatigue Fracture, Corrosion Pitting, Aluminum 7075, landing gear, FESEM, Finite Element Analysis, Failure Analysis 1. Introduction An executive transport military aircraft assigned to the 14 th Support Wing, Pratica di Mare Air Force Base, experienced loss of the main landing gear (MLG) left door during a standard flight (Fig. 1). In the aftermath of this serious occurrenc , th Chemistry Department of the Italian Air Force (IAF) Flight Test Center was tasked to lead a technical investigation aimed to clarify the root causes for the failure and to recommend how to prevent similar © 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 06 91292536. E-mail address: fabrizio.depaolis@am.difesa.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 © 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.2017.04.040