PSI - Issue 2_B

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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 Transition from multi-center fracture to fragmentation statistics under intensive loading Irina A. Bannikova a , *, Oleg B. Naimark a , Sergey V. Uvarov a a ICMM UB RAS, Academika Koroleva st.,1, Perm 614013, Russia Abstract Statistics of transiti n from dama e to fragmentation is studied bas d on th analysis of multi-scale mechanisms of nucleation and growth of cracks in hollow cylindrical (tub l r) specimens made of Al 2 O 3 ceramics. Specimens are loaded by underwater electrical wire explosion. Around 98% of the initial mass of the specimen was recovered as a fragments. The fragments were classified into two types: quasi-two-dimensional (2D) samples, the characteristic size of which d* was greater than (or equal to) the wall thickness of the tube d ; and three-dimensional (3D) samples of size d* < d . The analysis of the fragment geometry allows us to determine the mechanisms responsible for the formation of 2D and 3D fragme ts. The 2D fragments are formed by the large cracks (Mott mechanism) as a result of tube extension in the radial directi n. The 3D objects ar formed due to instability of fast crack propagation, which leads to microbranching, as was shown in Sharon (1996). The 3D fragments size distribution is governed by the power law, which corresponds to the microbranch distribution. The study of the influence of the initial sample porosity indicates that the distribution of the porosity is described by the power function with an exponent slightly differing from that of the fragments distribution. We suppose that both the initial porosity and crack instability influence th formation of small fragments. The preliminary analysis of the initial porosity f the material sh w us that th initial poros ty as a direct effect on th formation of 3D fragments. According to the scenario, the initial defects (pores) provide the conditions for multi-site fracture of ceramics under high rate loading. © 2016 The Authors. Published by Elsevier B.V. Peer-review under responsibility of the Scientific Com ittee of ECF21. 21st European Conference on Fracture, ECF21, 20-24 June 2016, Catania, Italy Transition from multi-center fracture to fragmentation statistics under intensive loading Irina A. Bannikova a , *, Oleg B. Naimark a , Sergey V. Uvarov a a ICMM UB RAS, Academika Koroleva st.,1, Perm 614013, Russia Abstract Statistics of transition from damage to fragmentation is studied based on the analysis of multi-scale mechanisms of nucleation and growth of cra ks in hollow cylindrical (tubular) specimens made of Al 2 O 3 ceramics. Specime s are loaded by u derwater electri l wire exp sion. Around 98% of the in tial mass of the specimen was recover d as a fr gments. Th fragments were classified int two types: quasi-two-dimensional (2D) samples, the cha a teristic size of which d* was greater than (or equal to) he wall thicknes of the tube d ; and three-dim nsional (3D) sample of size d* < . The an lysis of the fragment g ometry allow us o determine the m chanisms responsible for the formation of 2D and 3D fragments. The 2D fragments are formed by the large cracks (Mott echanism) as a result of tube extension in the dial direction. The 3D objects are formed due o instability f fast crack prop gation, which le ds to microbranching, as was show in Sharon (1996). Th 3D fragmen s size distribution is gov rned by the power law, which correspond to the microbranch distribution. The study of he nfluence of the initial sample porosity indicates that the distributi n of the p rosity is described by the power function with an expo ent light y differ ng from tha of t fragments distributi n. We suppose that both the initial p rosity a d crack instabilit in lue ce the formation of small fragmen s. The preliminary analysis of t e initial porosity of the material shows us that the initial poros ty has a direct eff ct on the for ation of 3D fragments. According to the scenario, the initial defects (pores) rovide the conditions or m lt -site f acture of ceramics under high rate loading. © 2016 The Authors. Published by Elsevier B.V. Peer-review under espons bility of the Scientific Committee of ECF21. Keywords: Fragmentation; ceramic tubes; multi-scale mechanisms; photographic technique; shape factor; porosity; electrical wire explosion. 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. © 2016 The Authors. Published by Elsevier B.V. Peer-review under responsibility of the Scientific Committee of PCF 2016. Keywords: High Pressure Turbine Blade; Creep; Finite Element Method; 3D Model; Simulation. Keywords: Fragmentation; ceramic tubes; multi-scale mechanisms; phot graphic technique; shape factor; porosity; electrical wire explosion.

* Corresponding author. Tel.: +7-963-883-5524. E-mail address: malgacheva@icmm.ru * Corresponding author. Tel.: +7-963-883-5524. E-mail address: malgacheva@icmm.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 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.2016.06.244