PSI - Issue 1

ScienceDirect Procedia Structural Integrity 1 (2016) 218–225 Available online at www.sciencedirect.com Av ilable online at ww.sciencedire t.com Sci nceDirect Structural Integ ity Procedia 00 (2016) 000 – 000 Available online at www.sciencedirect.com Structural Integrity Procedia 00 (2016) 000–000 Available online at www.sciencedirect.com Structural Integrity Procedia 00 (2016) 000–000 Available online at www.sciencedirect.com Structural Integrity Procedia 00 (2016) 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. XV Portuguese Conference on Fracture, PCF 2016, 10-12 February 2016, Pac¸o de Arcos, Portugal Galvanic corrosion of air raft bonded joints as a result of adhesive microcracks V. Anes a,b , R. S. Pedro b , E. Henriques a , M. Freitas a , L. Reis a, ∗ a idMEC, Instituto Superior Te´cnico, University of Lisbon, Av. Rovisco Pais, 1, 1049-001, Lisbon, Portugal b TAP Maintenance & Engineering, Hangar 5, 1704-801, Lisbon, Portugal Abstract This paper studies the root causes of a corrosion failure found in the Airbus A320 CFM56-5b intakes. This failure occurs in a dissimilar materials joint and is strongly related to the adhesive loss of integrity at very low temperatures. The ductility reduction of the adhesive at low temperatures promotes the microcracks formation within the adhesive layer of the bonded joint, which in turn sparks the corrosion process. These microcracks allow the infiltration of dust, moisture, contaminants and salt water in the interface between the adhesive and adherents, which promotes the creation of a dielectric between the joint adherents and consequently their galvanic corrosion. Results show that the thermal strains of the dissimilar joint materials at very low temperatures significantly reduces the adhesive load margin reserved for drag loads. Some rem rks are drawn in orde to improve the joi t corrosio resistance. © 2016 V. Anes et al. Publish d by Elsevier B.V. Peer-review under responsibil ty of the Scientific Committee of PCF 2016. Keywords: Aircraft bonded joint; epoxy adhesive microcracks; galvanic corrosion; aluminium alloys; adhesive selection; Scientific based research in corrosion of composite aircraft structures has been made during decades, especially in aluminium sandwich structures. Currently, the 2024 T3 (duraluminium) and 7075 T6 aluminium alloys are the most studied where the major focus has been on pre-treatments, coatings, and eco-friendly approaches in corrosion prevention processes Bierwagen et al. (2010). The front end of recent corrosion research is on the pursuit of alterna tive coatings based in nano-particles in order to achieve e ff ective barriers to corrosion in aluminium aerospace alloys Voevodin et al. (2006). Moreover, corrosion research has been also focused in corrosion resistance improvement of aluminium alloys by developing new heat treatments. The major objective is to reduce the aluminium alloys suscepti bility to stress-corrosion cracking, which has creating huge concerns about air transport safety Cina (1974). In general, the presence of corrosion damage reduce the fatigue lives of components to a severe extent and has been the focus of intense research in the 7075 T6 aluminium alloy DuQuesnay et al. (2003). Moreover, on this same alloy, studies were XV Portuguese Conference on Fracture, PCF 2016, 10-12 February 2016, Pac¸o de Arcos, Portugal Galvanic corrosion of aircraft bonded joints as a result of adhesive microcracks V. Anes a,b , R. S. Pedro b , E. Henriques a , M. Freitas a , L. Reis a, ∗ a idMEC, Instituto Superior Te´c ico, University of Lisbon, Av. Rovisco Pais, 1, 1049-001, Lisbon, Portugal b TAP Maintenance & Engineering, Hangar 5, 1704-801, Lisbon, Portugal Abstract This paper studies the root causes of a corrosion failur found in the Airbus A320 CFM56-5b intakes. This failure occurs in a dissimilar materials joint and is trongly related to the adhesive loss of integrity at very low temperatures. The ductility reduction of the adhesive at low temp ratures promotes the microcracks formation within the adhesive layer of the bonded joint, which in turn sparks the corrosion process. These microcracks allow the infiltration of dust, moistur , contami ants and salt water in th interface between the adhesive and adherents, which pro otes the creation of a dielectric between the joint adherents and conseque tly their galvanic corrosion. Results show that the thermal strains of the dissimilar joint materials at very low temperatures signific tly reduces the adhesive load margin reserv d for drag loads. Some remarks are drawn in order to improve the joint corrosion resistance. © 2016 V. Anes et al. Published by Elsevier B.V. Peer-revi w under responsibility of the Scientific Committee of PCF 2016. Keywords: Aircraft bonded joint; epoxy adhesive microcracks; galvanic corrosion; aluminium alloys; adhesive selection; 1. Introduction Scientific based research in corrosion of composite aircraft structures has been made during decades, especially in aluminium sandwich structures. Currently, the 2024 T3 (duraluminium) and 7075 T6 aluminium alloys are the most studied where the major focus has been on pre-treatments, coatings, and eco-friendly approaches in corrosion prevention processes Bierwagen et al. (2010). The front end of recent corrosion research is on the pursuit of alterna tive coatings based in nano-particles in order to achieve e ff ective barriers to corrosion in aluminium aerospace alloys Voevodin et al. (2006). Moreover, corrosion research has been also focused in corrosion resistance improvement of aluminium alloys by developing new heat treatments. The major objective is to reduce the aluminium alloys suscepti bility to stress-corrosion cracking, which has creating huge concerns about air transport safety Cina (1974). In general, the presence of corrosion damage reduce the fatigue lives of components to a severe extent and has been the focus of intense research in the 7075 T6 aluminium alloy DuQuesnay et al. (2003). Moreover, on this same alloy, studies were XV Portuguese Conference on Fracture, PCF 2016, 10-12 February 2016, Pac¸o de Arcos, Portugal alvanic corrosion of aircraft bonded joints as a result of adhesive microcracks V. Anes a,b , R. S. Pedro b , E. Henriques a , M. Freitas a , L. Reis a, ∗ a idMEC, I stituto Superior Te´cnico, University of Lisbon, Av. Rovisco Pais, 1, 1049-001, Lisbon, Portugal b TAP Maintenance & Engineering, Hangar 5, 1704-801, Lisbon, Portugal Abstract This paper studies the root causes of a corrosion failure found in the Airbus A320 CFM56-5b intakes. This failure occurs in a dissimilar materials joi and is strongly relat d to the adhesive loss of integrity at very low temperatures. The ductility reduction of the adhesive at low temperatures promotes the microcracks formation within the adhesive layer of the bonded joint, which in turn sparks the corrosion process. These microcracks allow the infiltration of dust, moisture, contaminants and salt water in the interface between the adhesive and adherents, which promotes the creation of a dielectric between the joint adherents and consequently their galvanic corrosion. Results show that the thermal strains of the dissimilar joint materials at very low temperatures significantly reduces the adhesive load margin reserved for drag loads. Some remarks are drawn in order to improve the joint corrosion resistance. © 2016 V. Anes et al. Published by Elsevier B.V. Peer-review under responsibility of the Scientific Committee of PCF 2016. Keywords: Air raft bonded joint; epoxy adhesive microcr cks; galvanic corrosion; luminium alloys; adhesive selection; 1. Introduction Scientific based esearch in corrosion of composite aircraft structures has been made during decades, especially in aluminium sandwich structures. Curr ntly, the 2024 T3 (duraluminium) and 7075 T6 aluminium alloys are the most studied where the major focus has been on pre-treatments, coatings, and eco-friendly approaches in corrosion prevention processes Bierwagen et al. (2010). The front end of recent corrosion research is on the pursuit of alterna tive coatings based in nano-particles in order to achieve e ff ective barriers to corrosion in aluminium aerospace alloys Voevodin et al. (2006). Moreover, corrosion research has been also focused in corrosion resistance improvement of aluminium alloys by developing new heat treatments. The major objective is to reduce the aluminium alloys suscepti bility to stress-corrosion cracking, which has creating huge concerns about air transport safety Cina (1974). In general, the presence of corrosion damage reduce the fatigue lives of components to a severe extent and has been the focus of intense research in the 7075 T6 aluminium alloy DuQuesnay et al. (2003). Moreover, on this same alloy, studies were Copyright © 2015 The Authors. Published by Elsevier B.V. This is an pen access rticle und r the CC BY-NC-ND l cense (http://creativecommons.org/l censes/by-nc-nd/4.0/). P r-review under resp nsibility of the Scientific Committee of PCF 2016. © 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. 1. Introduction

* Corresponding author. Tel.: +351 218419991. E-mail address: amd@tecnico.ulisboa.pt ∗ Luis Reis Tel.: + 351 966415585 E-mail address: luis.g.reis@tecnico.ulisboa.pt ∗ Luis Reis Tel.: + 351 966415585 E-mail address: luis.g.reis@tecnico.ulisboa.pt

2452-3216 © 2016 The Authors. Published by Elsevier B.V. Peer-review under responsibility of the Scientific Committee of PCF 2016. Copyright © 2015 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 PCF 2016. 10.1016/j.prostr.2016.02.030 2452-3216 © 2016 V. nes et al. Published by Elsevier B.V. Peer-review under responsibility of the Scientifi Committee of PCF 2016. ∗ Luis Reis Tel.: + 351 966415585 E-mail address: luis.g.reis@tecnico.ulisboa.pt 2452-3216 © 2016 V. A e et al. Published by Elsevier B.V. e r-review under responsibil ty of the Scientific Committee of PCF 2016. 2452-3216 © 2016 V. Anes et al. Published by Elsevier B.V. Peer-review under responsibility of the Scientific Committee of PCF 2016.