PSI - Issue 2_A

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 Struc ural Integrity 2 (2016) 2944–295 Available online at www.sciencedirect.com ScienceDire t Structural Integrity Procedia 00 (2016) 000 – 000 Available online at www.sciencedirect.com ScienceDirect 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. 21st European Conference on Fracture, ECF21, 20-24 June 2016, Catania, Italy Failur analysis of a motor vehicle coil spring Goran Vukelic a , *, Marino Brcic b a University of Rijeka, Faculty of Maritime Studies, Department of Marine Engineering and Ship Power Systems, Studentska 2, 51000 Rijeka, Croatia b University of Rijeka, Faculty of Engineering, Department of Engineering Mechanics, Vukovarska 58, 51000 Rijeka, Croatia Due to frequent failures of coil springs on a specific type of motor vehicle, analysis of possible causes of failures was performed. Analysis was done on a single coil spring removed from a vehicle after failing in service. Besides visual examination that revealed fracture to happen on a first bottom coil, several other experimental techniques were used in the failure analysis. Using optical microscopy evaluation of the basic microstructure of the fractured surface was performed and possible inclusions distinguished. Detailed s anning electron microscopy (SEM) examination at suitable magnifications was employed to characterize the fine microstructure of the fractured surface and reveal flaws that served as crack initiation points. Optical emission spectrometer with glow discharge source (GDS) sample stimulation was used to determin chemical composition of material used for spring fabrication. Additionally, hardness test was performed. Using results of the performed experimental analysis, possible causes of failure were recognized. Several factors, among them inherent material defect combined with material fatigue and helped by insufficient corrosion protection, caused failure of coil spring. Obtained results are valuable in predicting behaviour of coil springs mounted in other vehicles of the same type and can be taken as a reference in improving future design. Further analysis would include employing finite element method to determine stress levels in undamaged and damaged coil spring along with numerical estimation of fatigue life. © 2016 The Authors. Published by Elsevier B.V. Peer-review under responsibility of the Scientific Committee of ECF21. 21st European Conference on Fracture, ECF21, 20-24 June 2016, Catania, Italy Failure analysis of a motor vehicle coil spring Goran Vukelic a , *, Marino Brcic b a University of Rijeka, Faculty of Maritime Studies, Department of Marine Engineering and Ship Power Systems, Studentska 2, 51000 Rijeka, Croatia b University of Rijeka, Faculty of Engineering, Department of Engineering Mechanics, Vukovarska 58, 51000 Rijeka, Croatia Abstract Due to frequent failures of coil springs on a specific type of motor vehicle, analysis of possible causes of failures was performed. Analysis was done on a single coil spring removed from a vehicle aft r failing in service. Besid s vi ual examination that evealed fracture to happen first bottom coil, several other exp r m n al techniques were used n the failure nalys s. Using optical mi roscopy evaluation o the basic microstructure of th fractur d surface was performed and possible inclusions di tinguished. Detailed scanning electron microscopy (SEM) examination at suitable magnifications w s employed to characterize the fine micro t ucture of the fractured surface and reveal flaws that served as crack i itiation points. Optical mission spect ometer with glow dis ha ge source (GDS) sample stimulation as used to etermine chem cal composition of material used for spring fabricat on. Additionally, hardness test was performed. Using results of the performed experimental analysis, pos ible causes of ilure were recognized. Several factors, among th m inherent material defect combined with m teri fatigue and helped by ins fficient corr sion protection, caused failure of coil spring. Obtain d results are valuable in predicting behaviour of coil springs mo nted in other vehicles of the s m type and can be taken as refer nce in improving futu e design. Further analys s would incl d employing finite element method to determine stress levels in undamaged and damaged coil spring along with numerical estimation of fatigue l f . © 2016 The Authors. Published by Elsevier B.V. Peer-review under espons bility of the Scientific Committee of ECF21. Copyright © 2016 The Authors. Published y Elsevier B.V. This is an open access article under the CC BY-NC-ND license (http://creativ ommons.org/licenses/by-nc-nd/4.0/). Peer-review und r responsibility of the Scientific Committe of ECF21. Abstract

Keywords: coil spring, spring steel, failure analysis

© 2016 The Authors. Published by Elsevier B.V. Peer-review under responsibility of the Scientific Committee of PCF 2016. Keywords: coil spring, spring steel, failure analysis

Keywords: High Pressure Turbine Blade; Creep; Finite Element Method; 3D Model; Simulation.

* Corresponding author. Tel.: +385-51-338-411; fax: +385-51-336-755. E-mail address: gvukelic@pfri.hr * Corresponding author. Tel.: +385-51-338-411; fax: +385-51-336-755. E-mail address: gvukelic@pfri.hr

* Corresponding author. Tel.: +351 218419991. E-mail address: amd@tecnico.ulisboa.pt 2452-3216 © 201 6 The Authors. Published by Elsevier B.V. Peer-review under responsibility of the Scientific Committee of ECF21. 2452-3216 © 201 6 The Authors. Published by Elsevier B.V. Peer review under r sponsibility of the Scientific Committee of ECF21.

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.2016.06.368