PSI - Issue 2_A

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) 1125–1132 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 Fatigue crack initiation and growth on an extruded titanium alloy in gigacycle regime: comparison between tension and torsion loadings Alexander Nikitin a,b,c *, Thierry Palin-Luc c , Andrey Shanyavskiy d a ICAD Russian Academy of Science – 19/18, 2nd Brestskay street, Moscow, Russia b MAI – National Research University, 4, Volokolamskoe Hw, Moscow, Russia c Arts et Metiers Paris Tech, I2M, CNRS, Esplanade des Arts et Metiers, Talence, France d Aviaregister, Air.Sheremetievo-1, PO Box 54, Moscow reg., Chimkovskiy state, Russia Abstract This paper is focused on the analysis of fatigue crack initiation and growth mechanisms in defect free VT3-1 titanium alloy (similar to Ti6Al4V) in VHCF regime under tensile and torsion loadings. Fully reversed fatigue tests were carried out between 10 7 and 10 9 cycles at 20 kHz under constant amplitude loadings (no pulse-pause). SEM observations of the specimens fracture surfaces were carried out in order to compare the crack initiation mechanisms and the different crack growth stages under different loadings. It has been shown that subsurface crack initiation may appear under tension (as usual in gigacycle regime) but in o experiments no i clusi n was observ d i the “fish- ye”. Furthermore, subsurface crack initiatio was observed under torsion loading too, despite the maximum she r stress lo ation at the sp cimen surface. Under this loading, a “fish- ye” was obs rve to , but again without any inclusion in its c nter. Th suspected microstructural reasons resp nsible for subsurface crack initiations under t rsion loading could not be observed due to significant destru tion of the fracture patterns ( rack lips friction u der mixed mode). The results of the fatigue tests show a principal difference in crack initiation and early crack growth stage between tensile and torsion loadings. Torsion crack initiates on a plane of maximum shear stress (like in HCF regime) while tensile crack is on a plane of maximum normal stress. Sequences of changes in fracture surface roughness is the same for tensile and torsion loadings. 7 an 9 Copyright © 2016 The Authors. Published by Elsevier B.V. This is an open access ar icle under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/). Peer-review under resp nsibility 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. © 2016 The Authors. Published by Elsevier B.V. Peer-review under responsibility of the Scientific Committee of ECF21. Keywords: compressor disk; titanium alloy; very high cycle fatigue; ultrasonic; torsion; tension; crack initiation mechanism; crack growth; Keywords: compressor

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

* Corresponding author. Tel.: +7-965-436-59-80;. E-mail address: nikitin_alex@bk.ru

* 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 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.2016.06.144