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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 Micromechanical cohesive zone relations for ductile fracture Tuncay Yalc¸inkaya a, ∗ , Alan Cocks b a Middle East Technical University, Department of Aerospace Engineering, Ankara 06800, Turkey b University of Oxford, Department of Engineering Science, Parks Road, Oxford OX1 3PJ, UK Abstract This paper addresses the derivation of a micromechanically motivated incremental mixed-mode traction separation law in the context of cohesive zone modeling of crack propagation in ductile metallic materials. The formulation is based on the growth of an array of pores idealized as cylinders which are considered as the representative volume elements. An upper bound solution is applied for the deformation of he representative volume element and di ff ere t incremental traction-separation relations are obtained f r mixed-mode loading conditions. While most of the current tracti n-separation relations used in cohesive zone modeling consider phenomenological relations, in the current work micromechanical parameters such as size, shape and spacing of pores describe the level of damage and linkage of the pores characterizes the propagating crack. c � 2016 The Authors. Published by Elsevier B.V. Peer-review under responsibility of the Scientific Committ ee of ECF21. Keywords: ductile fracture; cohesive zone modeling; micromechanics; micro void growth; porous plasticity; limit load analysis 1. Introduction The underlying physical m chanism for the ductile fracture of engineering metallic materials is th generation of considerable porosity (void volume fraction), where micro voids nucleate, grow and coalesce. Typically the initial porosity is found to be in the range of 10 − 4 to 10 − 2 (see e.g. Tvergaard (1990), Thomason (1990)). The experimental studies illustrates that the voids start to coalesce and eventually ductile failure occurs when the void volume fraction reaches values from 0 . 1 to 0 . 3 (see e.g. Barbee et al. (1972), Beachem and Yoder (1973), Cortes (1992)). In ductile materials, the voids nucleate at inclusions and second–phase particles, by decohesion of the particle-matrix inter face or by particle cracking. Therefore, void growth is driven by plastic deformation of the surrounding matrix. This phenomenon has been subjected to extensive research and implemented in (porous) plasticity and creep models over the last 40 years (see e.g. McClintock (1968), Gurson (1977), Cocks and Ashby (1980), Tvergaard and Needleman (1984), Rousselier (1987), Cocks (1989), Gologanu et al. (1993), Gologanu et al. (1994)) and used for damage initia tion predictions. The main idea is that plasticity behavior of the material is governed by both the mean and deviatoric stresses including both material hardening and geometric softening e ff ects. 21st European Conference on Fracture, ECF21, 20-24 June 2016, Catania, Italy Micromechanical cohesive zone relations for ductile fracture Tuncay Yalc¸i kaya a, ∗ , Alan Cocks b a Middle East Technical University, Department of Aerospace Engineering, Ankara 06800, Turkey b University of Oxford, Department of Engineering Science, Parks Road, Oxford OX1 3PJ, UK Abstract This paper addresses the derivation of a micr mechanically m tivated incremental mixed-mode traction separation law in the c ntext of cohesive z e modeling of crack propagation in ductile metallic materials. Th formul tion is based on th growth of an array of por s idealized as cyli ders which are considered as the representative volume elements. An upper bound solution is applied for the def rmation of the repres ntative volume element and di ff erent incremental traction-separation relations are obtained for mixed-mode loading conditi ns. Whil most of the current traction-separation relations used in cohesive zone modeling consider phenomenological relations, in the current work micromechanical parameters such as size, shape and spacing of pores describe the level of damage and linkage of the pores characterizes the propagating crack. c � 2016 The Authors. Published by Elsevier B.V. Peer-review under responsibility of the Scientific Committ ee of ECF21. Keywords: ductile fracture; cohesive zone modeling; micromechanics; micro void growth; porous plasticity; limit load analysis 1. Introduction The underlying physical mechanism for he ductil fracture of engineering metallic materials is th gen ation of considerable porosity (void volume fraction), where micro voi s nucle te, gr w and coalesc . Typica ly the initial porosity is found to be in the rang of 10 − 4 to 10 − 2 (see e.g. Tv rgaard (1990), Thomason (1990)). The experimental studies illustrates that the voids start to coalesce and eventually ductil failure occurs when t void volume fraction reaches values from 0 . 1 to 0 . 3 (s e e.g. Barbee et al. (1972), Beachem and Yoder (1973), Co tes (1992)). In ductile materials, the voids ucleate at inclusions and second–phase particl s, by decohesion of he particle-matrix inter face or by particle cracking. Therefore, void growth is driven by pla tic deformation of the su roun ing matrix. This phenomenon has been subjected to extensive research nd implemented i (porous) plasticity an creep od ls over he last 40 years (s e e.g. McClin ock (1968), Gurson (1977), Cocks nd Ashby (1980), Tvergaard and Ne dleman (1984), Rousselier (1987), Cocks (1989), Golo anu t al. (1993), Gologanu et al. (1994)) and used for damage initia tion predictions. The main idea is that plasticity behavior of the material is governed by both the mean and deviatoric stresses including both material hardening and geometric softening e ff ects. 21st European Conference on Fracture, ECF21, 20-24 June 2016, Catania, Italy Micromechanical cohesive zone relations for ductile fracture Tuncay Yalc¸inkaya a, ∗ , Alan Cocks b a Middle East Technical University, Department of Aerospace Engineering, Ankara 06800, Turkey b University of Oxford, Department of Engineering Science, Parks Road, Oxford OX1 3PJ, UK Abstract This paper addresses the derivation of a micromechanically motivated incremental mixed-mode traction separation law in the context of cohesive zone modeling of crack propagation in ductile metallic materials. The formulation is based on the growth of an array of pores idealized as cylinders which are considered as the representative volume elements. An upper bound solution is applied for the deformation of the representative volume element and di ff erent incremental traction-separation relations are obtained for mixed-mode loading conditions. While most of the current traction-separation relations used in cohesive z ne modeling cons der phenomenological relations, in the current work micromechanical parameters such as size, shape and spacing of pores describe the level of damage and linkage of the pores characterizes the propagating crack. c � 2016 The Authors. Published by Elsevier B.V. Peer-review under responsibility of the Scientific Committ ee of ECF21. Keywords: ductile fracture; cohesive zon modeling; micro echa ics; mic o void growth; porous plasticit ; limit loa analysis 1. Introduction The underlying physical mechanism for the ductile fracture of engineering metallic materials is the generation of considerable porosity (void volume fraction), where micro voids nucleate, grow and coalesce. Typically the initial porosity is found t be in the range of 10 − 4 to 10 − 2 (see e.g. Tvergaard (1990), Thomason (1990)). The experimental studies illustrates that the voids start to coalesce and eventually ductile failure occurs when the void volume fraction reaches values from 0 . 1 to 0 . 3 (see e.g. Barbee et al. (1972), Beachem and Yoder (1973), Cortes (1992)). In ductile materials, the voids nucleate at inclusions and second–phase particles, by decohesion of the particle-matrix inter face or by particle cracking. Therefore, void growth is driven by plastic deformation of the surrounding matrix. This phenomenon has been subjected to extensive research and implemented in (porous) plasticity and creep models over the last 40 years (see e.g. McClintock (1968), Gurson (1977), Cocks and Ashby (1980), Tvergaard and Needleman (1984), Rousselier (1987), Cocks (1989), Gologanu et al. (1993), Gologanu et al. (1994)) and used for damage initia tion predictions. The main idea is that plasticity behavior of the material is governed by both the mean and deviatoric stresses including both material hardening and geometric softening e ff ects. Copyright © 2016 The Authors. Published by Elsevier B.V. T is is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/). er-review under esponsibility 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 ∗ Corresponding author. Tel.: + 90-312-210-4258 ; fax: + 90-312-210-4250. E-mail address: yalcinka@metu.edu.tr ∗ Corresponding author. Tel.: + 90-312-210-4258 ; fax: + 90-312-210-4250. E-mail address: yalcinka@metu.edu.tr

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.2016.06.217 2452-3 16 c � 2016 The Authors. Published by Elsevi r B.V. Peer-review under responsibility of the Scientific Comm tt ee f ECF21. ∗ Corresponding author. Tel.: + 90-312-210-4258 ; fax: + 90-312-210-4250. E-mail address: yalcinka@metu.edu.tr 2452-3216 c � 2016 The Authors. Published by Elsevier B.V. Peer-review under responsibility of the Scientific Committ ee of ECF21. 2452-3216 c � 2016 The Authors. Published by Elsevier B.V. Peer-review under responsibility of the Scientific Committ ee of ECF21.