PSI- Issue 9

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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. © 2018 The Authors. Published y Elsevier B.V. Peer-review under responsibility of the Gruppo Italiano Fr ttura (IGF) ExCo. IGF Workshop “Fracture and Structural Integrity” Luminescence from impact- and abrasive-damaged ZnS ceramics Alexandre Chmel a,* , Anatolij Dunaev b , Igor Shcherbakov a . Alfred Sinani a . a Ioffe Institute, 26 Polytekhnicheskaya, St Petersburg, 194021, Russia b Vavilov State Opt cal Institute, 192171 St. Petersburg, R ssia Abstract IR windows made of ZnS ceramics serve as protective elements for the thermal imaging systems established on mobile carriers, whereon they suffer from weathering and dust impacts. In this study, the erosion of ZnS ceramics was simulated by the abrasive damaging of polished specimens, and the response of the crystal lattice on the external forcing was investigated by the method of photoluminescence (PL). Impacts of isolated hard particles were modelled with the discrete shocks of a pointed striker, and fractoluminescence (FL) from the damaged spot was detected. The FL evidenced that the impact forcing triggers a two-stage mechanism of damage nucleation in this ductile ceramic. The dislocation motion at the stage of initial deformation followed by the interatomic bonds breakage at the stage of cracking. The PL data showed the higher stability of crystallites in chemically vapor deposited (CVD) ZnS ceramics as compared with the same compounds obtained by the hot pressing (HP) or physical vapor deposition (PVD) technologies. The abrasive treatment of ZnS-CVD did not affect significantly the entirety of crystallites because of plasticity of intercrystallite substance, in which the impact-induced tension dissipated. Undamaged crystallites retained their optical properties that is did not exhibit additional absorbance. Thus, the decrease of the transmissive capability under particle impacts occurs predominantly due to light scattering on the newly-formed surface irregularities. © 2018 The Authors. Published by Elsevier B.V. Peer-review under responsibility of the Gruppo Italiano Frattura (IGF) ExCo. Keywords : ZnS ceramics; Damage resistance; Photoluminescence; Fractoluminescence. IGF Workshop “Fracture and Structural Integrity” Luminescence from impact- and abrasive-damaged ZnS ceramics Alexandre Chmel a,* , Anatolij Dunaev b , Igor Shcherbakov a . Alfred Sinani a . a Ioffe Institute, 26 Polytekh icheskaya, St Petersburg, 194021, Russia b Vavilov State Optical Institute, 192171 St. Petersburg, Russia Abstract IR windows made of ZnS ceramics serve as protective elements for the therm l imaging systems established on mobil carriers, whereo they suffer from weatheri g and dust impacts. In this study, the erosion of ZnS ceramics was simulated by the abrasive damaging of polished specimens, and the response of the crystal lattice on the external forcing was investigated by the method of phot l mi s ce (P ). Impacts of isolated hard particles were modelled with the discrete shocks of a pointed striker, nd fractoluminescence (FL) from the damaged spot was detected. The FL evidenced that the impact forcing triggers a two-stag mechanism of damage nucle tion in this ductile ceramic. The islocation motion at the stage of initial deformation followed by the interatomic bonds breakage at the stage of cracking. The PL data showed the higher stability of crystallites in chemically r ited (C ) ZnS ceramics as compar d with the same compounds obtained by the hot pr ssing (HP) or physical vapor deposition (PVD) technologies. The abrasive treatment of ZnS-CVD did not affect significantly the entirety of crystallites because f pl sticity of inte crystallite subst n e, in which the impact-induced tension diss pat d. Unda aged crystallites retained their optical properties t at is did not exhibit additional absorba ce. Thus, the decr ase of the transmissive capability und r particl impacts occurs predominantly due to light scattering on the newly-formed surface irregularities. © 2018 The Authors. Published by Elsevier B.V. Peer-review under responsibility of the Gruppo Italiano Frattura (IGF) ExCo. Keywords : ZnS ceramics; Damage resistance; Photoluminescence; Fractoluminescence.

© 2016 The Authors. Published by Elsevier B.V. Peer-review under responsibility of the Scientific Committee of PCF 2016. * Corresponding author. Tel.: +79119183982; fax: +78122971017. E-mail address: chmel@mail.ioffe.ru 1. Introduction * Corresponding author. Tel.: +79119183982; fax: +78122971017. E-mail address: chmel@mail.ioffe.ru 1. Introduction

Keywords: High Pressure Turbine Blade; Creep; Finite Element Method; 3D Model; Simulation. ZnS compound, which is transparent in the atmospheric window (8–14 µm), is used for manufacturing protecting windows for the forward-looking infrared (FLIR) devices, Klein et al. (1986) and Chang et al. (2003) as well as in solar cells, Jilbert and Field (2000), attackable by solid dust particles and meteorological precipitate, Peterson (1979) and Hasan (1990). In the most bulk applications, zinc sulfide in the form of ceramics is the preferential choice as compared to its single-crystal counterpart since the polycrystalline structure reduces anisotropy in the optical ZnS compound, which is transparent in the atmospheric window (8–14 µm), is used for manufacturing protecting windows for the forward-looking infrared (FLIR) devices, Klein et al. (1986) and Chang et al. (2003) as well as in solar cells, Jilbert and Field (2000), attackable by solid dust particles and eteorological precipitate, Peterson (1979) and Hasan (1990). In the most bulk applications, zinc sulfide in the form of ceramics is the preferential choice as compared to its single-crystal counterpart since the polycrystalline structure reduces anisotropy in the optical

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 Gruppo Italiano Frattura (IGF) ExCo. 10.1016/j.prostr.2018.06.002 * Corresponding author. Tel.: +351 218419991. E-mail address: amd@tecnico.ulisboa.pt 2452 3216 © 2018 Th Authors. Published by Elsevier B.V. Peer-review under responsibility of the Gruppo Italiano Frattura (IGF) ExCo. 2452-3216 © 2018 The Authors. Published by Elsevier B.V. Peer-review under responsibility of the Gruppo Italiano Frattura (IGF) ExCo.