PSI - Issue 7

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ScienceDirect Available online at www.sciencedirect.com Av ilable o line at ww.sciencedire t.com Sci nceDirect Structural Integrity Procedia 00 (2016) 000 – 000 Procedia Structu al Integrity 7 (2017) 254–261 Structural Integrity Procedia 00 (2017) 000–000 Available online at www.sciencedirect.com ScienceDirect Structural Integrity Procedia 00 (2017) 000–000 ScienceDirect

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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. Copyright © 2017 The Authors. Published by Elsevier B.V. Peer-review und r responsibility of the Scientific Committe of the 3rd International Symposium on Fatigue Design and Material Defects. 3rd International Symposium on Fatigue Design and Material Defects, FDMD 2017, 19-22 September 2017, Lecco, Italy Determination of local stress intensity factors at microstructurally tortu us crack fronts under remote mode II loading Stanislav Žák a * , Jana Horníková a,b , Pavel Šandera a,b , Tomáš Vojtek a , Jaroslav Pokluda a,b a Brno University of Technology, Central European Institute of Technology, Purkyňova 123, 612 00 Brno, Czech Republic b Brno University of Technology, Faculty of Mechanical Engineering, Technická 2, 616 69 Brno, Czech Republic Abstract The real crack geometries are mostly not ideally smooth and fracture parameters calculated for cracks with tortuous fronts and rough flanks differ from results obtained for smooth cracks. he finite element methods allow us to determine fracture parameters for such kinds of cracks and, moreover, some useful an ytical approaches can also be applied to simplified crack front geometries. Several authors already reported on these geometrically induced shielding effects but, in most cases, only the loading under the opening mode I was considered in the frame of simple 2D models of tortuous crack front. This work presents results of the investigation of local mixed-mode loading along a real-like, tortuous crack front loaded under the remote mode II. The employed numerical methods enabled us to get sufficiently precise values of all local components of loading modes I, II and III along the crack front. A comparison of these values with those obtained from analytical formulae related to a simplified form of the tortuous crack front with an equal linear roughness led to a very good agreement. The results could be used for a correction of the mode II effective fatigue threshold as measured for the polycrystalline ARMCO iron under an assumption of a straight precrack front. It is expected that such a correction, based on the roughness data of the real precrack, will shift the measured fatigue threshold data very close to those theoretical obtained from multiscale approaches. © 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. 3rd International Symposium on Fatigue Design and Material Defects, FDMD 2017, 19-22 September 2017, Lecco, Italy Dete minati of local stress i tensity facto s at microstructurally tortuous crack fronts under remote mode II loading Stanislav Žák a * , Jana Horníková a,b , Pavel Šandera a,b , Tomáš Vojtek a , Jaroslav Pokluda a,b a Brno University of Technology, Central European Institute of Technology, Purkyňova 123, 612 00 Brno, Czech Republic b Brno University of Technology, Faculty of Mechanical Engineering, Technická 2, 616 69 Brno, Czech Republic Abstract The real crack geometries are mostly ot ideally smooth and fracture parameters calculated for cracks with t rtuous fronts and rough flanks differ from results obtained f r smooth cracks. The finite element methods allow us to determine fracture parameters for such kinds of cracks and, moreover, some useful analytical approaches can also be applied to simplified crack front geometries. Several authors already reported on these geometrically ind ced shielding effects but, in most cases, only the loading under the opening mode I was considered in the frame of simple 2D models of tortuous crack front. This work presents results of t e nvestigation of local m xed-mode loading along a real-like, tortuous crack front loaded under the re ote mo e II. The emplo ed numerical methods enabled us to g t sufficiently precise values of all local comp nents of loading modes I, II and III along the crack front. A comparison of these values with those obtained from analytical formulae related to a simplified form of the tortu us crack front with an equal linear roughness led to a very good agreement. The results could be used for a correction of the mode II effecti e fatigue threshold as measured for the polycrystalline ARMCO iron under an assumption of a straight precrack front. It is expected that such a correction, based on the roughness data of the real precrack, will shift the measured fatigue threshold data very close to those theoretical obtained from multiscale approaches. © 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. © 2016 The Authors. Published by Elsevier B.V. Peer-review under responsibility of the Scientific Committee of PCF 2016. Keywords: shear mode loading; micro-tortuous crack front; Compact-Tension-Shear specimen; geometrical shielding effect Keywords: shear mode loading; micro-tortuous crack front; Compact-Tension-Shear specimen; geometrical shielding effect

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

* Corresponding author. Tel.: +420 603 799 811. E-mail address: Stanislav.zak@ceitec.vutbr.cz * Corresponding author. Tel.: +420 603 799 811. E-mail address: Stanislav.zak@ceitec.vutbr.cz

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

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.2017.11.086

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