PSI - Issue 13

ScienceDirect Available online at www.sciencedirect.com Available online at www.sciencedire t.com ScienceDirect Structural Integrity Procedia 00 (2016) 000 – 000 Procedia Structu al Integrity 13 (2018) 334–339 Available online at www.sciencedirect.com ScienceDirect StructuralIntegrity Procedia 00 (2018) 000 – 000 Available online at www.sciencedirect.com ScienceDirect StructuralIntegrity 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 Working life estimate of the tubular T-joint by application of the LEFM concept Jelena Djoković a , Ruži Nik lić b,c *, Branislav Hadzima b , Dušan Arsić c , Libor Trško b a Technical Faculty of Bor, University of Belgrade, Vojske Jugoslavije 12, 19210 Bor,Serbia b Research Center, University of Žilina, Univerzitna 2415/1, Žilina 010 26, Slovakia; c Faculty of Engineering, University of Kragujevac, Sestre Janjić 6, 34000 Kragujevac, Serbia The crack growth in tubular joints usually occurs along the weld's toe. That is the point where the chord and brace intersect. The semi-elliptical crack appears in this area from the initial flaw that was created during the welding. Sensitivity to fatigue depends on combination of cyclic loading, initial defects, environmental influences and the hot spot stresses, which are result of the walls' bending during the loading of a structure. The principles of the linear elastic fracture mechanics (LEFM) are applied here to crack growth in the tubular T-joint, subjected to axial load, in-plane and anti-plane bending. Influences of the level and type of loading, as well as of the joint's geometrical characteristics, on the fatigue crack propagation and consequently on the working life of the welded joint, are considered. Based on the conducted analysis, which implies a set of assumptions, one can draw sufficiently relevant conclusion on the r maining working life of t e tubular T-joint. The assumptions included: the crack shap is s mi elliptic l, here is only one crack propagating through the tub wall, the cyclic plastic zone at the crack tip is small with respect to other geometrical ariables and the crack grows only if the difference between the stress intensity factor values at maxim l and mini al loads is greater than he s r ss inte sity factor necessary for th fatigue crack growth initiati n. Results r pr sented in the form o diagrams from which can be seen that for the same load level the longer working life s achieved for the axial load of the joint than for the in-plane bending, while the values for the anti-pla e bending lie between these two limiting results. © 2018 The Authors. Published by Elsevier B.V. Peer-review under responsibility of the ECF22 organizers. © 2018 The Authors. Published by Elsevier B.V. Peer-review under responsibility of the ECF22 organizers. ECF22 - Loading and Environmental effects on Structural Integrity Working life estimate of the tubular T-joint by applica ion of the LEFM concept Jelena Djoković a , Ružica Nikolić b,c *, Branislav Hadzima b , Dušan Arsić c , Libor Trško b a Technical Faculty of Bor, University of Belgrade, Vojske Jugoslavije 12, 19210 Bor,Serbia b R sear h Center, Unive sity of Žilina, Unive zitna 2415/1, Žilin 010 26, Slovakia; c Faculty of E gineering, University of Kragujevac, Sestre Janj ć 6, 34000 Kragujevac, Serbia Abstract The crack growth in tubular joints usually occurs along the weld's toe. That is the point where the chord and brace intersect. The semi-elliptical crack appears in this area from the initial fla that was created during the welding. Sensitivity to fatigue depends on combination of cyclic loading, initial defects, nvironmental influen es an the hot spot stresses, which are result of the walls' bending during the loading of a structure. The principles of the li ear elastic fracture mechanics (LEFM) are applied here to crack growth in the tubular T-joint, subjected to axial load, in-plane and nti-plane bending. Influences of the lev l and type of l ading, as ell as of the joint's geometrical characteristics, on the fatigue crack propagation and consequently on the working life of the weld d joint, are considered. Based on the conducted analysis, which implies a set of assumptions, e can draw sufficiently relevant conclusion on the remai ing working lif of the tubular T-joint. The ssumptions included: the crack shape is semi elliptical, there is only one crack propagating through the tube wall, the cyclic plastic zone at the crack tip is small with respect to oth r geometrical variables and the crack grows o ly if the difference between the stress int nsity factor values at maximal an minimal loads is greater than the stress intensity f cto nece sary for the f tigue crack growth initiation. Result re presented in the form of diagrams from which can be seen that for the same load lev l the longer working life is achieved for the axial loa f t j int than for the in-plane bending, whil the values for the anti-plan bending lie between these two limiting results. © 2018 The Authors. Published by Elsevier B.V. Peer-review under responsibility of the ECF22 organizers. Abstract

© 2016 The Authors. Published by Elsevier B.V. Peer-review under responsibility of the Scientific Committee of PCF 2016. Keywords: tubular T- joint; fatigue crack; Paris law; LEFM Keywords: tubular T- joint; fatigue crack; Paris law; LEFM

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

* Corresponding author. Tel.: +421415137627. E-mail address: ruzicarnikolic@yahoo.com * Corresponding author. Tel.: +421415137627. E-mail ad ress: r zicarnikolic@yahoo.com

* 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 responsibility of the ECF22 organizers.

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.2018.12.056