PSI - Issue 2_A

ScienceDirect Available online at www.sciencedirect.com Av ilable o line at www.sciencedire t.com ienceDirect Structural Integrity Procedia 00 (2016) 000 – 000 Procedia Struc ural Integrity 2 (2016) 3447–3458 Available online at www.sciencedirect.com ScienceDirect 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 Crack propagation in layers under small-scale yielding J. P. Vafa, S. J. Fariborz* Department of Mechanical Engineering, Amirkabir University of Technology (Tehran Polytechnic), 424, Hafez Avenue, Tehran 158754413, Iran Abstract The stress field is obtained in an isotropic elastic layer containing an edge dislocation. The dislocation solution is used to derive integral equations for a cracked layer. These are a set of Cauchy singular integral equations which are solved numerically for the density of dislocations on a crack surface. The density of dislocations is utilized to determine stress components in the vicinity of a crack tip. The stress field contains singular as well as non-singular terms. Assuming small scale yielding, the von-Mises yield criterion is adopted to define a plastic region around a crack tip under the plane-stress situation. Several examples are solved and the plastic region developed by a crack with different orientations and loadings is specified. Moreover, in another example, plastic regions round the tips of two interacting cracks are defined. The geometry of the plastic regions is utilized to obtain a crack propagation angle. © 2016 The Authors. Published by Elsevier B.V. Peer-review under responsibility of the Scientific Committee of ECF21. Keywords: Elastic layer; Multiple cracks; Plastic region; Crack propagation angle. 1. Introduction The extent of a plastic region around a crack tip is of utmost importance in the fracture behavior of metallic structures [Banks and Garlick (1984)]. It is well-known that in ductile materials plastic zone around a crack tip has a shielding effect; hence, enhances the material resistance against crack driving force [Zhu et al (2010)]. The shape and size of a plastic zone around a crack tip was used by, Golos and Wasiluk (2000), and Bian and Kim (2004), to evaluate the angle of crack propagation under mixed mode deformation. 21st European Conference on Fracture, ECF21, 20-24 June 2016, Catania, Italy Crack propagation in layers under small-scale yielding J. P. Vafa, S. J. Fariborz* Department of Mechanical Engineering, Amirkabir University of Technology (Tehran Polytechnic), 424, Hafez Avenue, Tehran 158754413, Ir n Abstract The stress field is obtained in an isotropic elastic layer containing an edge dislocation. The dislocation solution is used to derive int gral equation for cracked layer. Thes re a set of Cauchy singular integral equations which are solved numerically for th density of dislocations on a crack surface. The density of dislocations is utilized to determine stress components in the vicinity of a crack tip. The s res field ontains singular as well as non-singular terms. Assuming s all cale yielding, the von-Mises yield criterion is adopted to define a plastic re ion around a crack tip under the plane-stress situ tion. S veral examples are solved an the plastic region eveloped by a cra k with different orientations and loadings is sp cified. Moreover, in another example, plastic region around the tips of two interacting cracks are d fined. The ge metry of th plastic regi ns is utilized to obtain a crack propagation angle. © 2016 The Authors. Published by Elsevier B.V. Peer-review under espons bility of the Scientific Committee of ECF21. Keywords: Elastic layer; Multiple cracks; Plastic region; Crack propagation angle. 1. Int oduction The extent of a plastic region around a crack tip is of utmost importance in the fracture behavior of metallic structur s [Banks and Garlick (1984)]. It is well- nown that in ductile materials plastic zone around a crack tip has a hielding effect; he ce, enhances the material resistance against crack driving force [Zhu et al (2010)]. The sha e nd ize of a plastic zone around a crack tip was used by, Golos and Wasiluk (2000), and Bian and Kim (2004), to evaluate the angle of crack propagation under mixed mo e deformation. 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.

* Corresponding author. Tel.: +351 218419991. E-mail address: amd@tecnico.ulisboa.pt 2452-3216 © 2016 The Authors. Published by Elsevier B.V. Peer-review und r responsibil ty 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.: +98 2164543460; fax: +98 2166419736. E-mail address: sjfariborz@yahoo.com * Corresponding author. Tel.: +98 2164543460; fax: +98 2166419736. E-mail ad ress: sjfariborz@yahoo.com

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.2016.06.430