PSI - Issue 2_B

ScienceDirect Available online at www.sciencedirect.com Av ilable online at ww.sciencedire t.com cienceDirect Structural Integrity Procedia 00 (2016) 000 – 000 Procedia Struc ural Integrity 2 (2016) 3439–3446 Available online at www.sciencedirect.com Sci nceDirect Structural Integrity Procedia 00 (2016) 000 – 000 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 On propagation of interface cracks in bi-layered strip in relati n t delamination of coatings from substrates of final thickness K.B. Ustinov* A.Yu. Ishlinsky Institute for Problems in Mechanics RAS, prospect Vernadskogo 101-1, Moscow, 119526, Russia The problem of a coatings delamination from a substrate is considered. Both the delaminated part of the coating and substrate are modelled as plates with a special attention to the boundary conditions, which are considered as generalized elastic clamping. For this type of boundary conditions the angle of rotation nd components of the displacement vector at the clamping point are related to the acting bending moment and components of the resulting force vector at that point by means of 3x3 matrix of elastic compliance. Such type of boundary conditions appeared from the solution of the problem of a bilayered strip with the semi-infinite interface crack loaded at infinity. The analytical solution of this problem for the particular relation between the elastic constants of the layers (zero second Dundurs ’ parameter) is obtained by reducing it to the homogeneous matrix Riemann boundary value problem solved by matrix factorization for two particular cases: (1) equal thickness of both layers; (2) thickness of one of the layers (corresponding to the substrate) being much more than the thickness of the other, so that this layer may be considered as a half-plane. For the general case of the arbitrary elastic constants and layers thicknesses the approximate solution has been obtained. The approximation involves neglecting the influence of the normal to interface stresses to the shear displacements and shear stresses to the normal displacements. According to the obtained solutions the asymptotics for the relative displacements of the separated layers for the points, remote from the crack tip, correspond to the deflection of plate (beam) with the described above boundary conditions. The fracture parameters (stress intensity factors and energy release rates) have also been obtained. Using the obtained solution the problem on buckling of the delaminated coatings is addressed. It has been shown that for a wide range of parameters the ratio of the critical stress, corresponding to buckling of the delaminated parts of coatings and the critical stress of a rigidly clamped plate is determined by a single nondimensional parameter, which is a combination of the elastic constants of the coating and substrate, and a combination of the geometrical parameters of the model. © 2016 The Authors. Published by Elsevier B.V. Peer-review under responsibility of the Scientific Committee of ECF21. 21st European Conference on Fracture, ECF21, 20-24 June 2016, Catania, Italy On propagation of interface cracks in bi-layered strip in relation to delamination of coatings from substrates of final thickness K.B. Ustinov* A.Yu. Ishlinsky Institute for Problems in Mechanics RAS, prospect Vernadskogo 101-1, Moscow, 119526, Russia Abstract The problem of a coatings delamination from a substrate is considered. Both the delaminated part of the coating and substrate are mode l d as plates with a special attention to the boundary conditions, w ich ar consid red s generalized elastic clamping. For this type of boundary conditions th angle f rotatio and mponents of t e displacement vector at the clamping point are related to the acting bending mome t and components of the resulting force vec or at that point by means of 3x3 atrix of elastic compliance. Such type of boundary conditions appeared from the solution of the problem f a ilay red strip with the semi-infinite interface cra k loaded at i finity. The a alytical soluti n of this pr blem for the particular relation between elastic co stants o the layers (zero seco d Dundurs ’ parameter) is obtained by reducing it to the homogeneous matrix Ri mann boundary value probl m solved by matrix factorization for two particular cases: (1) equal thickness of both layers; (2) th ckness of o e of the layers (corresponding to the subst ate) being much more than the thickness of the other, s that thi layer may be considered as half-plane. F r the general case of the arbitrary elastic constants and layers thicknesses the approximat solution has be n obt ined. The approximation involves neglecting the influe ce of the normal to interface stresses to the shear di plac ments a d shear stresses to the ormal displacements. According to the obtained solutions th asymp otics for the relative of the separated layers for the po nts, r ote from the crack ip, correspond to the deflection f plate (beam) with the described abov boundary conditi ns. The fracture parameters (st ess intensity factors and energy release rates) have also be n obtaine . Using the obtained solution the p oblem on buckling of the delam nated c atings is addressed. It h s been shown that f r a wide range of parameters the ratio of the critical stress, corresponding to buckling of the delaminated parts of coatings and the crit cal stress of a igidly clamped plate is determined by a single no dimensional param ter, wh ch is a combination of the elastic constant of the coating and substr , an a combination of th ge metrical parameters of the model. © 2016 The Authors. Published by Elsevier B.V. Peer-review under espons bility of the Scientific Committee of ECF21. Keywords: interface crack, coatings, delamination, elastic cla ping, buckling, matrix Riemann boundary value problem, matrix factorization 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: interface crack, coatings, delamination, elastic clamping, buckling, matrix Riemann boundary value problem, matrix factorization Abstract

* Corresponding author. Tel.: +351 218419991. E-mail address: amd@tecnico.ulisboa.pt 2452-3216 © 2016 The Authors. Published by Elsevier B.V. Peer-review un r responsibility of the Scientific Committee of ECF21. 2452-3216 © 2016 The Authors. Published by Elsevier B.V. Peer review under r sponsibility of the Scientific Committee of ECF21. * Corresponding author. Tel.: +7-495-434-3447; fax: +7-499-739-9531. E-mail address: ustinov@ipmnet.ru * Corresponding author. Tel.: +7-495-434-3447; fax: +7-499-739-9531. E-mail ad ress: stinov@ipmnet.ru

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.2016.06.429