PSI - Issue 4

ScienceDirect Available online at www.sciencedirect.com Av ilable o line at www.sciencedire t.com ScienceDirect Structural Integrity Procedia 00 (2016) 000 – 000 P o edi Structural Integr ty 4 (2017) 42–47 Available online at www.sciencedirect.com ScienceDirect 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. ESIS TC24 Workshop "Integrity of Railway Structures", 24-25 October 2016, Leoben, Austria Effect of residual stresses on the fatigue lifetime of railway axle Pavel Hutař a , Pavel Pokorný a , Jan Poduška a , Rostislav Fajkoš b , Luboš Náhlík a * a CEITEC IPM, Institute of Physics of Materials, Academy of Sciences of the Czech Republic, v. v. i., Žižkova 22, 616 62 Brno, Czech Republ ic b BONATRANS GROUP, a. s., Revoluční 1234, 735 94 Bohumín, Czech R epublic The operation of railway axles should fulfill at least two main demands: safety and low operation costs. A significant part of operation costs is given by the length of regular inspection intervals which should reveal potential fatigue cracks in railway axle. The detection of cracks is of a probabilistic nature, therefore their detection is not ensured in all cases. For the safe operation of trains, an existence of potential i itial crack should be considered on the axle surface and residual fatigue lifetime should be conservatively determined for this case. Reliable pr cedure of residual fatigue lifetime estimation should take into account real axle geometry, material characteristics and loading of the railway axle. This paper shows methodology for determination of residual fatigue lifetime (RFL) based on the fracture mechanics approach, taking into account real spectrum of the loading cycles, existence of press-fitted wheels and surface residual stresses given by the thermo-mechanical surface treatment of the railway axle. It is demonstrated that the effect of the residual stresses is significant and should not be neglected in the numerical estimation of residual fatigue lifetime of the axle. © 2017 The Authors. Published by Elsevier B.V. Peer-review under responsibility of the Scientific Committee of ESIS TC24. Keywords: Railway axle; residual fatigue lifetime; residual stresses; inspection intervals; numerical simulation 1. Introduction On s of the critical compon nts of trains are railway axles, see references Zerbst et al. (2005), Zerbst et al. (2013) and Zerbst et al. (2013b). It is known that railway axles can include defects like cracks or surface scratches, which can lead to fatigue crack initiation and propagation. Unfortunately, the detection of such (in certain cases ESIS TC24 Workshop "Integrity of Railway Structures", 24-25 October 2016, Leoben, Austria Effect of residual stresses on the fatigue lifetime of railway axle Pavel Hutař a , Pavel Pokorný a , Jan Poduška a , Rostislav Fajkoš b , Luboš Náhlík a * a CEITEC IPM, Institute of Physics of Materials, Academy of Sciences of the Czech Republic, v. v. i., Žižkova 22, 616 62 Brno, Czech Republ ic b BONATRANS GROUP, a. s., Revoluční 1234, 735 94 Bohumín, Czech R epublic Abstract The peration of railway axl s should fulfill at least two mai demands: safety an low operation costs. A significant part of operation costs is given by the length of regular inspection intervals which should reveal potential fatigue crack in railway axle. The detection of cracks is of probabilistic nature, th refore th ir detection is not ensure in all cases. For th saf operation of trains, an existence of potential initial crack should be considered on the axle surface and residual fatigue lifetime should be conservatively determined for this case. Reliable procedure of residual fatigue lifetime stimation shoul take into account real axle geometry, material characteristics a d loading of the railw y axle. This paper shows m thodology f r determination of residual fatigue lifetime (RFL) based o the fr ture mechanics approach, taking into acc unt re l spectr m of the loading cycles, existence of press-fitted wheels and surface residual stres es given by the therm -mechanical surface treatment of the railway axle. It is demonstrated that the effect of the residual stresses is significant and should not be neglected in the numerical estimation of residual fatigue lifetime of the axle. © 2017 The Authors. Published by Elsevier B.V. Peer-review under responsibility of the Scientific Committee of ESIS TC24. Keywords: Railway axle; residual fatigue lifetime; residual stresses; inspection intervals; numerical simulation 1. Introduction Ones of the critical components of trains are railway axles, see references Zerbst et al. (2005), Zerbst et al. (2013) and Zerbst et al. (2013b). It is known that railway axles can include defects like cracks or surface scratches, which can lead to fatigue crack initiation and propagation. Unfortunately, the detection of such (in certain cases Copyright © 2017. The Authors. Published by Elsevier B.V. Peer-review und responsibility of the Scientific Co mittee of ESIS TC24. © 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. Abstract

* Corresponding author. Tel.: +420 532 290 358 E-mail address: nahlik@ipm.cz * Correspon ing aut or. Tel.: +420 532 290 358 E-mail address: nahlik@ipm.cz

2452-3216 © 2016 The Authors. Published by Elsevier B.V. Peer-review under responsibility of the Scientific Committee of PCF 2016. 2452-3216 Copyright  2017. The Authors. Published by Elsevier B.V. Peer-review under responsibility of the Scientific Committee of ESIS TC24 10.1016/j.prostr.2017.07.005 * Corresponding author. Tel.: +351 218419991. E-mail address: amd@tecnico.ulisboa.pt 2452 3216 © 2017 Th Authors. Published by Elsevier B.V. Peer-review under responsibility of the Scientific Committee of ESIS TC24. 2452-3216 © 2017 The Authors. Published by Elsevier B.V. Peer-review under responsibility of the Scientific Committee of ESIS TC24.