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) 48–55 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 Safe Life Prediction of Railway Axles Hans-Jakob Schindler a, * a Mat-Tec AG, Unterer Graben 27, 8401 Winterthur, Switzerland Residual stresses play an important role in fatigue crack growth in railway axles. Due to crack closure, they affect not only the stress ratio R but add directly to the effective range of the cyclic crack load in terms of stress intensity factor. In order to account for this effect in a safe life analysis, the stress intensity factor K Irs due to the residual stress is required. The cut-compliance method is a suitable means to determine K Irs . The method is described briefly, and by an example it is shown how it can e applied to railway axles. The obtained residual stresses turned out to be compressive in the vicinity of the surface, which is beneficial for the fatigue performance of the axle. If these stresses are accounted for in the crack growth law, the calculated safe life in case of a pre-existing crack-like defect is increased dramatically. Furthermore, the effect of the press-fit of the wheels is investigated. The corresponding stresses were calculated by FEM. Actually, these stresses represent another type of residual stresses and can be superimposed to the measured residual stresses in the analysis. They also affect the crack growth rate significantly. © 2017 The Authors. Published by Elsevier B.V. Peer-review under responsibility of the Scientific Committee of ESIS TC24. Keywords: Railway axle, safe life, fatigue, residual stress, cut-compliance method, press-fit, crack growth 1. Introduction The geometry of a railway-axle is relatively simple, the material is well known and the fatigue load is relatively well defined. Nevertheless, as recently discussed by Gänser et al. (2016), theoretical predictions of crack growth often deviate by far from experimental data even in case of well-defined artificial initial cracks and under well- ESIS TC24 Workshop "Integrity of Railway Structures", 24-25 October 2016, Leoben, Austria Effect of Residual Stresses on Safe Life Prediction of Railway Axles Hans-Jakob Schindler a, * a Mat-Tec AG, Unterer Graben 27, 8401 Winterthur, Switzerland Abstract Residual stresses play an important role in fatigue crack growth in railway axles. Due to crack closure, they affect not only the stress ratio R but add directly to the effective range of the cyclic crack load in terms of stress intensity factor. In order to account for this effect in a safe life analysis, th stress intensity factor K I s due to the resi ual stress is required. The cut-complianc metho is a suit ble means to determine K Irs . The method is escribed briefly, and by an example it is s own how it can be applied to railway axles. The obtained residual stress turned out to be compressive in the vicinity of the surf ce, which is benefici l for the fatigue performance of th axle. If these st esses are account d f in the cra k growth law, the calculated safe life in c se of a pre-exi ting crack-like defect is in re se dramatically. Furthermore, the ffect of the press-fit of the wheels is inve tigate . The corresponding stresses were calculated by FEM. Actually, these tress s represent another type of residual tresses and can b superi posed to the measur d residual stresses in the analysis. They also affect the crack growth rate significantly. © 2017 The Autho s. Published by Elsevier B.V. Peer-review under responsibility of the Scientific Committee of ESIS TC24. Keywords: Railway axle, safe life, fatigue, residual stress, cut-compliance method, press-fit, crack growth 1. Introduction The geometry of a railway-axle is relatively si ple, the material is well known and the fatigue l ad is relatively well defined. Nevertheless, as recently discussed by Gänser et al. (2016), theoretical predictions of crack growth often deviate by far from experimental data even in case of well-defined artificial initial cracks and under well- 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.: +41 52 202 54 44 E-mail address: schindler@mat-tec.ch * Correspon ing aut or. Tel.: +41 52 202 54 44 E-mail address: schindler@mat-tec.ch

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.2017.07.008 * 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.