PSI - Issue 2_A

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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 2D-lattice modelling of crack propagation induced by fluid injection in heterogeneous quasi-brittle materials David Gre´goire ∗ , Vincent Lefort, Olivier Nouailletas, Gilles Pijaudier-Cabot Universite´ Pau & Pays Adour, LFCR (UMR5150), Campus Montaury, 64600 Anglet, France Abstract Characterizing the path of a hydraulic fracture in a heterogeneous medium is one of the challenges of current research on hydraulic fracturing. We present here a 2D lattice hydro-mechanical model for this purpose. Natural joints are represented introducing elements with a plastic-damage behaviour. The action of fluid pressure on skeleton is represented using Biot’s theory. The interactions of cracks on fluid flow are represented considering a Poisueille’s flow between two parallel plates. The model is simplified by neglecting the e ff ect of deformation in the equation governing fluid flow. Numerical coupling is achieved with a staggered coupling scheme. We consider first the propagation of fractur restricted to th homogeneous case. The numerical model is compared to analytical solutions. It is found that the model is consistent with LEFM in he pure mechanic l case, and with analytical solutions from the literature in the case where the leak o ff is d minant. In very tight formations, deviations are obs rved, as expected, cause f the assumption in the flow m del. Finally, the influence of a natural joint of finite length cro sed by the fracture is shown. Tw cases re considered, the case of a j int perpendicular to the crack and the case of an inclined joint. In the first case, the crack passes through the joint, which is damaged due to the intrusion of the fluid. In the second case, the crack follows the joint and propagatio starts again from the tip. 21st European Conference on Fracture, ECF21, 20-24 June 2016, Catania, Italy 2D-lattice modelling of crack propagation induced by fluid injection in heterogeneous quasi-brittle materials David Gre´goire ∗ , Vincent Lefort, Olivier Nouailletas, Gilles Pijaudier-Cabot Universite´ Pau & Pays Adour, LFCR (UMR5150), Campus Montaury, 64600 Anglet, France Abstract Characterizing the path of a hydraulic fracture in a heterogeneous medium is one of the challenges of current research on hydraulic fracturing. We present here a 2D lattice hydro-mechanical model for this purpose. Natural joints are represented i troducing elements with a plastic-damage behaviour. The action of fluid pressure on skeleton is represented using Biot’s theory. The interactions of cracks on fluid flow are represented considering a Poisueille’s flow between two parallel plates. The model is simplified by neglecting the e ff ect of deformation in the equation governing fluid flow. Numerical coupling is achieved with a staggered coupling scheme. We consider first the propagation of fracture restricted to the homogeneous case. The numerical model is compared to analytical solutions. It is found that the model is consistent with LEFM in the pure mechanical case, and with analytical solutions from the literature in the case where the leak o ff is dominant. In very tight formations, deviations are observed, as expected, because of the assumption in the flow model. Finally, the influence of a natural joint of finite length crossed by the fracture is shown. Two cases are considered, the case of a joint perpendicular to the crack and the case of an inclined joint. In the first case, the crack passes through the joint, which is damaged due to the intrusion of the fluid. In the second case, the crack follows the joint and propagation starts again from the tip. © 2016 The Authors. Published by Elsevier B.V. Peer-review under responsibility of the Scientific Committee of ECF21. Keywords: Fracture Process Zone; Hydro-mechanical Coupling; Lattice Analysis; Jointed rock 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/). 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. © 2016 The Authors. Published by Elsevier B.V. Peer-review under responsibility of the Scientific Committee of ECF21. Keywords: Fracture Process Zone; H dro-mechanical Coupling; Lattice Analysis; Jointed rock

Keywords: High Pressure Turbine Blade; Creep; Finite Element Method; 3D Model; Simulation.

1. Introduction 1. Introduction

Crack propagation under fluid injection is a coupled and complex problem with various applications, from magma transport in the lithosphere to oil and gas reservoir stimulation from the 40’s (Economides and Nolte, 2000). Di ff erent coupled e ff ects have been studied in the literature such as the interaction between di ff erent stimulated cracks Crack propagation under fluid injection is a coupled and complex problem with various applications, from magma transport in the lithosphere to oil and gas reservoir stimulation from the 40’s (Economides and Nolte, 2000). Di ff erent coupled e ff ects have been studied in the literature such as the interaction between di ff erent stimulated cracks

* Corresponding author. Tel.: +351 218419991. E-mail address: amd@tecnico.ulisboa.pt ∗ Corresponding author. Tel.: + 33-5-5957-4479 ; fax: + 33-5-5957-4439. E-mail address: david.gregoire@univ-pau.fr ∗ Corresponding author. Tel.: + 33-5-5957-4479 ; fax: + 33-5-5957-4439. E-mail address: david.gregoire@univ-pau.fr

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.2016.06.337 2452-3216 © 2016 The Authors. Published by Elsevier B.V. Peer-review und r responsibility of the Scientifi Committee of ECF21. 2452-3216 © 2016 The Authors. Published by Elsevier B.V. Peer-review under responsibility of the Scientific Committee of ECF21.