PSI - Issue 7

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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 Structu al Integrity 7 (2017) 321–326 Structural Integrity Procedia 00 (2017) 000–000 Available online at www.sciencedirect.com ScienceDirect Structural Integrity Procedia 00 (2017) 000–000 ScienceDirect

www.elsevier.com/locate/procedia

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. Copyright © 2017 The Authors. Published by Elsevier B.V. Peer-review under responsibility f the Scien ific Committee of the 3rd International Symposium on Fatigue Design and Material Def cts. 3rd International Symposium on Fatigue Design and Material Defects, FDMD 2017, 19-22 September 2017, Lecco, Italy Investigation of changing failure mechanisms in the VHCF regime caused by different strengths of a martensitic steel A. Giertler*, K. Koschella, U. Krupp Institute of Materials Design and Structural Integrity, University of Applied Sciences Osnabrück, Faculty of Engineering and Computer Science, Albrechtstr. 30, 49076 Osnabrück, Germany Abstract The present study gives an overview of recent investigations dealing with the fatigue behaviour of the tempered martensitic steel 50CrMo4 (Fe-0.5wt%C-1wt%Cr) in the HCF and VHCF regime by taking into account a variation in material strength, by modifying the heat treatment parameters. The parameters for the tempering treatment were adapted t receive two material conditions with 37HRC and 57HRC, respectively. Subsequently, fatigue specimens were machined from the heat-treated bars for fatigue tests in an ultrasonic ( f =20000Hz) and a resonance ( f =95Hz) fatigue testing machine under fully reversed loading ( R =-1) at laboratory air atmosphere. It was found that the dominant fatigue and fracture mechanisms change with increasing material strength. For 37HRC moderate-strength specimens crack initiation was shown to occur on the specimen surface within Cr depleted bands (segregation bands) as the dominant fatigue damage mechanism. Contrary to that, only internal crack initiation at non-metallic inclusions was observed for the high strength 57HRC condition. Furthermore, the completely different crack initiation mechanisms of the two heat treatment conditions were assessed by applying the Murakami approach relating the fatigue limit with the size of non-metallic inclusions. © 2017 The Authors. Published by Elsevier B.V. Peer-review under responsibility of the Scientific Committee of the 3rd International Symposium on Fatigue Design and Material Defects. Keywords: tempering steel; fatigue crack; VHCF; EBSD; thermography 3rd International Symposium on Fatigue Design and Material Defects, FDMD 2017, 19-22 September 2017, Lecco, Italy Investi ation of changing failure mechanisms in the VHCF regime caused by different strengths of a martensitic steel A. Giertler*, K. Koschella, U. Krupp Institute of Materials Design and Structural Integrity, University of Applied Sciences Osnabrück, Faculty of Engineering and Computer Science, Albrechtstr. 30, 49076 Osnabrück, Germany Abstract The present study gives an overview of recent investigations dealing with the fatigue behaviour of the tempered martensitic steel 50CrM 4 (Fe-0.5wt% -1wt%Cr) in the HCF and VHCF regime by taking into account a variati n in material strength, by modifying the heat treatment parameters. The paramet rs for the temp ring treatment were adapted to r ceive two materi l conditi ns with 37HRC and 57HRC, respectively. Subsequently, fatigue specimens were m chined from the heat-tr ated bars for fatigue tests in an ultra onic ( f =20000Hz) and a resonance ( f =95Hz) fatigue testing machine under fully reversed loading ( R =-1) at laboratory air atmosphere. It was found that the dominant fatigue and fracture mec anisms change with increasing m terial str ngth. For 37HRC moderate-strength specimens crack i itiation was shown to ccur on the sp cimen surface within Cr depl ted band (segr gation bands) as the dominant fatigue damage mechanism. Contr ry to that, only inter al crack initiation at non-metallic inclusions was observed for the high strength 57HRC condition. Further ore, the completely different crack initiation mechanisms of the two heat treatment conditions were assessed by applying the Murakami approach relating the fatigue limit with the size of non-metallic inclusions. © 2017 The Authors. Published by Elsevier B.V. Peer-review under responsibility of the Scientific Committee of the 3rd International Symposium on Fatigue Design and Material D fects.

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

* Corresponding author. Tel.: +49-541-969-3215; fax: +49-541-969-2958. E-mail address: a.giertler@hs-osnabrueck.de

2452-3216 © 2017 The Authors. Published by Elsevier B.V. Peer-review under responsibility of the Scientific Committee of the 3rd International Symposium on Fatigue Design and Material Defects. 2452-3216 © 2017 The Authors. Published by Elsevier B.V. Peer-review under responsibility of the Scientific Committee of the 3rd International Symposium on Fatigue Design and Material Defects. * Corresponding author. Tel.: +49-541-969-3215; fax: +49-541-969-2958. E-mail address: a.giertler@hs-osnabrueck.de

* Corresponding author. Tel.: +351 218419991. E-mail address: amd@tecnico.ulisboa.pt

2452-3216 Copyright  2017 The Authors. Published by Elsevier B.V. Peer-review under responsibility of the Scientific Committee of the 3rd International Symposium on Fatigue Design and Material Defects. 10.1016/j.prostr.2017.11.095

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