PSI - Issue 2_B

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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 Influ nce of a neighbour fibre on the onset and growth of a fibre-matrix debond under biaxial loading. A study by Finite Fracture Mechanics at linear elastic interfaces. Mar Mun˜oz-Reja a , Luis Ta´vara a, ∗ , Vladislav Manti ˇ c a , Pietro Cornetti b a Grupo de Elasticidad y Resistencia de Materiales, Escuela T e´cnica Superior de Ingenier´ıa Universidad de Sevilla, Camino de los Descubrimientos s / n, 41092 Sevilla, Spain b Dipartimento di Ingegneria Strutturale, Edile e Geotecnica, Politecnico di Torino, Corso Duca degli Abruzzi 24, 10129 Torino, Italy Abstract The aim of the present paper is to study the interaction between two aligned fibres embedded in a large matrix. Special atte ntion is taken to the influence of the presence of a second fibre on the fibre-matrix interface failure. The Linear Elastic Brittle Interface Model (LEBIM) is used to model the fibre-matrix interface behaviour. In LEBIM, an undamaged point of the interface behave s as a linear-elastic spring with a linear relation between tr actions and relative displacements. In order to model an interface point failure, the LEBIM follows a law which takes into account the variation of the fracture toughness with the fracture mode mixity. The failure criterion used in this study is based on a Finite Fracture Mechanics (FFM) approach, where the stress and ener gy criteria are appropriately coupled. The FFM approach applied to the LEBIM is able to make the values of interface strength and fracture toughness to be independent. In the original LEBIM these values are restrictively tied. The present methodolo gy uses a 2D Boundary Element Method (BEM) code to carry out the analysis of interfaces failure. The numerical results show that the d istance between the fibres a ff ects the position where the debond (interface crack) onset occurs. It also influences the subsequent debond growth along the interfaces. As could be expected, for increasing distances the results tend to the single-fibre problem solution. c � 2016 The Authors. Published by Elsevier B.V. Peer-review under responsibility of the Scientific Committ ee of ECF21. Keywords: Interface crack; LEBIM; FFM; BEM 21st European Conference on Fracture, ECF21, 20-24 June 2016, Catania, Italy Influence of a neighbour fibre on the onset and growth of a fibre-matrix debond under biaxial loading. A study by Finite Fracture Mechanics at linear elastic interfaces. Mar Mun˜oz-Reja a , Luis Ta´vara a, ∗ , Vladislav Manti ˇ c a , Pietro Cornetti b a Grupo de Elasticidad y Resistencia de Materiales, Escuela T e´cnica Superior de Ingenier´ıa Universidad de Sevilla, Camino de los Descubrimientos s / n, 41092 Sevilla, Spain b Dipartimento di Ingegneria Strutturale, Edile e Geotecnica, Politecnico di Torino, Corso Duca degli Abruzzi 24, 10129 Torino, Italy Abstract The aim of the present paper is to study the interaction between two aligned fibres embedded in a large matrix. Special atte ntion is taken to the influence of the presence of a second fibre on the fibre-matrix interface failure. The Linear Elastic Brittle Interface Model (LEBIM) is used to model the fibre-matrix interface behaviour. In LEBIM, an undamaged point of the interface behave s as a linear-elastic spring with a linear relation between tr actions and relative displacements. In order to model an interface point failure, the LEBIM follows a law which takes into account the variation of the fracture toughness with the fracture mode mixity. The fa lure cr terion used in this study is based on a Finite Fractu Mechanics (FFM) approach, where the stress and e er gy criteria are appropriately coupled. The FFM approach applied to the LEBIM is able o make the values of interface strength a d fracture toughness t be independent. In the original LEBIM these values are restrictively tied. The pr sent method lo gy uses a 2D Boundary Element Method (BEM) code to carry out the analysis of interfaces failure. The numerical results show that the d istance between the fibres a ff cts the position where the debo d (interface crack) onset occurs. It also influences the subsequent debond growth along the interfaces. As could be expected, for increasing distances the results tend to the single-fibre problem solution. c � 2016 The Authors. Published by Elsevier B.V. Peer-review under responsibility of the Scientific Committ ee of ECF21. Keywords: Interface crack; LEBIM; FFM; BEM Copyright © 2016 The Authors. Published y Elsevier B.V. T is is an ope access article under the CC BY-NC-ND license (http://creativ ommons.org/licenses/by-nc-nd/4.0/). P re iew 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.

1. Introduction 1. Introduction

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

The integrity of composite structures is determined by the strength and durability of their interfaces and adhesive joints, among other conditions. The adhesion (or cohesion) must be guaranteed at several levels of such structures, namely at fibre-matrix interfaces, interfaces between unidirectional plies in laminates, joints between laminates an d with other materials, etc. Thus, one of the main concerns to design this kind of structures is the adequate characteri zation of the interfaces between adherents at micro, meso an d macro-scale. The integrity of composite structures is determined by the strength and durability of their interfaces and adhesive joints, among other conditions. The adhesion (or cohesion) must be guaranteed at several levels of such structures, namely at fibre-matrix interfaces, interfaces between unidirectional plies in laminates, joints between laminates an d with other materials, etc. Thus, one of the main concerns to design this kind of structures is the adequate characteri zation of the interfaces between adherents at micro, meso an d macro-scale.

* Corresponding author. Tel.: +351 218419991. E-mail address: amd@tecnico.ulisboa.pt ∗ Corresponding author. Tel.: + 34-954487299 ; fax: + 34-954461637. E-mail address: ltavara@us.es ∗ Corresponding author. Tel.: + 34-954487299 ; fax: + 34-954461637. E-mail address: ltavara@us.es

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.2016.06.254 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.