PSI - Issue 13

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 Structural Integrity 13 (2018) 2071–2 76 Available online at www.sciencedirect.com ScienceDirect Structural Integrity Procedia 00 (2018) 000 – 000 Available online at www.sciencedirect.com ScienceDirect Structural Integrity Procedia 00 (2018) 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. ECF22 - Loading and Environmental effects on Structural Integrity Very high cycle fatigue behaviour of 42CrMo4 steel with plate-like alumina inclusions M. Seleznev a, *, J. Gleinig a , K. Y. Wong b , A. Weidner a , H. Biermann a Institute of Materials Engineering, Technische Universität Bergakademie Freiberg, Gustav-Zeuner-Str. 5, 09599 Freiberg, Germany b Institute of Stochastics, Technische Universität Bergakademie Freiberg, Gustav-Zeuner-Str. 5, 09599 Freiberg, Germany Recent progress in steel refining shows significant reduction of non-metallic inclusions (NMIs) of which alumina (Al 2 O 3 ) is one of the most problematic. Among other refining methods, metal melt filtration by ceramic foam filters shows promising results in steel cleaning. In the present work the influence of alumina inclusions on the fatigue behavior is investigated after the reaction of steel melt with filters. Different batches are compared where carbon-bonded alumina foam filters with different coatings were introduced into the steel melt of 42CrMo4 for 10 s (so called “finger test”) . Fatigue tests were performed using ultrasonic fatigue testing (USFT) up to 10 9 cycles. Specimens were nitrided in order to prevent crack initiation from the surface and to study internal failure on NMIs. Surface hardening of quenched steel increased fatigue limit significantly. Metallographic sections were analyzed using optical and scanning electro mi oscopy (SEM) for the estimation of NMIs distribution properties. NMI size distribution analysis based on maximum Feret diameter (instead of area) is found to be an effective method for detecting plate-shaped inclusions. Fracture surfaces after fatigue tests were investigated by methods of SEM and confocal laser scanning microscopy (CLSM), revealing that plate-like NMIs initiate crack with all their area even being inclined to the crack plane. Properties of crack initiating NMIs – alumina plates and MnS dendrites – are compared and analyzed. Formation of alumina NMI as plate lead to significant enlargement of its stress-concentrating area in comparison to the spherical shape of the same volume. Thus, total NMI content reduction in steel could give no fatigue limit improvement if NMI morphology changes from spherical to plate-like. © 2018 The Authors. Published by Elsevier B.V. Peer-review under responsibility of the ECF22 organizers. © 2018 Th Authors. Published by Elsevier B.V. Peer-review under responsibility f the ECF22 organizers. ECF22 - Loading and Environmental effects on Structural Integrity Very high cycle fatigue behaviour of 42CrMo4 steel with plate-like l mina inclusions M. Seleznev a, *, J. Gleinig a , K. Y. Wong b , A. Weidner a , H. Biermann a a Institute of Materials Engineering, Technische Universität Bergakademie Freiberg, Gustav-Zeuner-Str. 5, 09599 Freiberg, Germany b Institute of Stochast cs, Technis e Universität Bergakademie Freiberg, Gustav-Zeuner-Str. 5, 09 99 Freibe g, Germany Abstract Recent progress in steel refining shows significant reduction of non-metallic inclusions (NMIs) of which alumina (Al 2 O 3 ) is one of the most problematic. Among other refining methods, metal melt filtr tion by ceramic foam filters shows promising results in steel cleaning. In the present work the i flue ce of alumina inclusions on the fatigue behavior is investigated after the reaction of t l m lt with filters. Different batches ar omp red where ca bon-bond d alumina foam filters with different coatings were introduced into the steel melt of 42CrMo4 for 10 s (so called “finger test”) . Fatig e tests were performed using ultrasonic fatigu testing (USFT) up to 10 9 cycles. Specimens were nitrided in order to prevent crack initiation from the surface and to study internal failure on NMIs. Surface hardening of quench d steel increase fatigue limit significantly. Metallographic s ctions were analyzed using optical and scanning electron microscopy (SEM) for the estimation of NMIs distribution properties. NMI ize distribution analysis based on maximum Feret diameter (instead of area) is found t be an effective method for detecting plate-shaped i clusions. Fracture surfaces after fatigue t sts were investig ted by meth ds of SEM and confocal laser scanning microscopy (CLSM), reve ling that plate-lik NMIs initiate crack with all th ir area even being inclined to the cr ck plane. Properties of crack initiating NMIs – alumina plates and M S dendrites – are compared and analyzed. Formation of alumina NMI as plate lead to significant enlargement of its stress-concentrating area in comparison to the spherical shape of the s me volume. Thus, total NMI content reduction in steel could give no fatigue limit improvement if NMI morphology changes from spherical to plate-like. © 2018 The Authors. Published by Elsevier B.V. Peer-review under responsibility of the ECF22 organizers. Keywords: Ultrasonic fatigue testing (USFT), very high cycle fatigue (VHCF), confocal laser scanning microscopy (CLSM), non-metallic inclusion (NMI), plate-l ke inclusions © 2016 The Authors. Published by Elsevier B.V. Peer-review under responsibility of the Scientific Committee of PCF 2016. Keywords: Ultrasonic fatigue testing (USFT), very high cycle fatigue (VHCF), confocal laser scanning microscopy (CLSM), non-metallic inclusions (NMI), plate-like inclusions Abstract

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 © 2018 The Authors. Published by Elsevier B.V. Peer-review under responsibility of the ECF22 organizers. 2452-3216 © 2018 The Authors. Published by Elsevier B.V. Peer review under r sponsibility of the ECF22 organizers. * Corresponding author. Tel.: +49-3731-39-4034. E-mail address: Mikhail.Seleznev@iwt.tu-freiberg.de * Corresponding author. Tel.: +49-3731-39-4034. E-mail ad ress: Mikhail.Seleznev@iwt.tu-freiberg.de

2452-3216 © 2016 The Authors. Published by Elsevier B.V. Peer-review under responsibility of the Scientific Committee of PCF 2016.

2452-3216  2018 The Authors. Published by Elsevier B.V. Peer-review under responsibility of the ECF22 organizers. 10.1016/j.prostr.2018.12.206