PSI - Issue 2_B

ScienceDirect Available online at www.sciencedirect.com Av ilable o line at ww.sciencedire t.com ienceDirect Structural Integrity Procedia 00 (2016) 000 – 000 Procedia Struc ural Integrity 2 (2016) 1207–1212 ScienceDirect 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 Investigation of the damage mechanisms during very high cycle fatigue (VHCF) of a tempered carbon steel A. Giertler*, U. Krupp University of Applied Sciences Osnabrück, Faculty of Engineering and Computer Science, Albrechtstr. 30, 49076 Osnabrück, Germany Abstract The study is an overview of recent investigations dealing with the fatigue damage in the HCF and VHCF regime of 0.5C-1Cr martensitic steel (German designation: 1.7228) in a tempered condition. The experimental part is focussed on the microst uctural chara terization regarding crystallographic orientation, reconstru tion and grain size distribution of prior austenite grains as well as metallographic investigations. Electrolytically polished cylindrical bulk specimens have been loaded under fully reversed (R=-1) loading condition using an ultrasonic fatigue testing machine (f=20000Hz) and an electro-mechanical resonance fatigue testing machine (f=95Hz). By means of a light microscope attached to the testing systems, fatigue crack initiation and propagation were correlated to the material microstructure and the specimens fatigue life. The application of a fast and high resolution thermography camera system in combination with the resonance testing system allows to use the heat dissipation determined on the surface of the fatig e specimen as a measure of specific fatigue damage. Th tested specimens have been carefully investigate by means of scann ng electron m croscopy (SEM) in omb nation with automated electron back-scatter diffraction (EBSD) and energy dispersive X-ray (EDX) analysis. It was found that under HCF and VHCF loading conditions crack initiation is caused by slip band formation between the martensitic laths structure, which leads to microcrack initiation and propagation. The propagation of microcracks is sensitive to changing crystallographic orientations when crossing a grain boundary. In case of run-out specimens (10 9 cycles) microcracks of the length of several microns have been found that were blocked by prior austenite grain boundaries which act in this case as effective barriers against microcrack propagation. © 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 Investigation of the damage mechanisms du ing very high cycle fatigue (VHCF) of a tempered carbon steel A. Giertler*, U. Krupp University of Applied Sciences Osnabrück, Faculty of Engineering and Computer Science, Albrechtstr. 30, 49076 Osnabrück, Germany Abstract The study is an overview of recent investigations dealing with the fatigue damage in the HCF and VHCF regime of 0.5C-1Cr martensitic steel (German designation: 1.7228) in a tempered condition. The experimental part is focussed on the microstructural characterization regarding crystallographic orientation, reconstruction and grain size distribution of prior austenite grains as well as metallographic investigations. Electrolytically polished cylindrical bulk specimens have been loaded under fully reversed (R=-1) loading condition using an ultrasonic fatigue testing machine (f=20000Hz) and an electro-mechanical resonance fatigue testing machine (f=95Hz). By means of a light microscope attached to the testing systems, fatigue crack initiation and propagation were correlated to the material microstructure and the specimens fatigue life. The application of a fast and high resolution thermography camera system in combination with the resonance testing system allows to use the heat dissipation determined on the surface of the fatigue specimen as a measure of specific fatigue damage. The tested specimens have been carefully investigated by means of scanning electron micro copy (SEM) in combination with automated electron back-scatter diffraction (EBSD) and en rgy dispersive X-ray (EDX) analysis. I was found that under HCF and VHCF loading conditions crack initiation is caused by slip band formation between the martensitic laths structure, which leads to microcrack initiation and propagation. The propagation of microcracks is sensitive to changing crystallographic orientations when crossing a grain boundary. In case of run-out specimens (10 9 cycles) microcracks of the length of several microns have been found that were blocked by prior austenite grain boundaries which act in this case as effective barriers against microcrack propagation. © 2016 The Authors. Published by Elsevier B.V. Peer-review under responsibility of the Scientific Committee of ECF21. Copyright © 2016 The Authors. Published by Elsevier B.V. This is an open access article under the CC BY-NC-ND license (http://c ativecommon .org/l censes/by-nc-nd/4.0/). Peer-review under responsibility of the Scientific Committee of ECF21. © 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.: +351 218419991. E-mail address: amd@tecnico.ulisboa.pt 2452-3216 © 2016 The Authors. Published by Elsevier B.V. Peer-review under responsibility 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 ECF21. * Corresponding author. Tel.: +49-541-969-3215; fax: +49-541-969-2958. E-mail address: a.giertler@hs-osnabrueck.de * Corresponding author. Tel.: +49-541-969-3215; fax: +49-541-969-2958. E-mail address: a.giertler@hs-osnabrueck.de

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.2016.06.154