PSI - Issue 2_A

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) 1319–1326 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 Cortical Bone as a Biomimetic Model for the Design of New Composites Flavia Libonati*, Laura Vergani Deparment of Mechanical Engineering, Politecnico di Milano, Milano, Italy Abstract Composite materials are widely used to build structures for their great mechanical performance combined with a low weight. However, the relatively low toughness of some composite materials is often a limitation as it can cause sudden failure. At present, there is a need for new lightweight materials with a good combination of strength and toughness, to be used for a variety of structural applications. Strength and toughness are the key requirements for structural materials. However, they are often mutually exclusive. Examples of effective design solutions can be found in natural materials, showing an optimal strength toughness balance. Such materials can be a good source of inspiration for the design of new smart materials, by following a biomimetic approach. Among natural materials, bone tissue is an intriguing one. Bone combines few meagre constituents, hydroxyapatite and collagen, as building blocks to build up a complex hierarchical structure, reaching remarkable mechanical properties and a large amplification in toughness not observed in synthetic counterparts. For this reason, bone can be considered as a biomimetic model material that many researchers have recently tried to mimic adopting different techniques. In this study, we take ins iration from bone to design and manufacture new FRC (fiber-reinforced composite) materials inspired by the micr stru ture of cortical bone, with the aim of mimicking some toughening mechanisms and improving the toughness of conventional composites. We focus on the microstructural level, since the fundamental toughening mechanisms occur at the microscale, and we mimic the main features involved in the fracture process in our new design. The choice of the key features to be mimicked in th biomimetic material design process is guided by a previous experimental campaign performed on bovine cortical bone. Here we describe the design of a new bio-inspired material and an experimental campaign to assess the mechanical performance and th failure modes. The sults of the tests allow us to c nfirm the promising mechanical characteristics of such material, compared to our previous design solutions and to similar classic structural composites (e.g. laminates). Moreover, the failure modes show many similarities with some of the toughening mechanisms occurring in cortical bone, confirming the key role, played by the mimicked bo e-inspired microstructural features, in determining and enhancing the fracture toughness of the compos tes. 21st European Conference on Fracture, ECF21, 20-24 June 2016, Catania, Italy Cortical Bone as a Biomimetic Model for the Design of New Composites Flavia Libonati*, Laura Vergani Deparment of Mechanical Engineering, Politecnico di Milano, Milano, Italy Abstract Composite materials are widely used to build structures for their great mechanical performance combined with a low weight. However, the relatively low toughness of some composite materials is often a limitation as it can cause sudden failure. At present, there is a need for new lightweight materials with a good combination of strength and toughness, to be used for a variety of structural applications. Strength and toughness are the key requirements for structural materials. However, they are often mutually exclusive. Examples of effective design solutions can be found in natural materials, showing an optimal strength toughness balance. Such materials can be a good source of inspiration for the design of new smart materials, by following a biomimetic appr ach. Among natur l ma erials, bone tissu i n intriguing one. Bone combines few meag e constituents, hydroxy pati e and collagen, as uilding blocks to b ild up a c mplex hierarchical s ructur , reaching remarkable m chanical properties and a large amplification in toughness not observed in synthetic c unterparts. For this reason, bon can be conside as a biomimetic model material that many researchers have recently tried to mimi adopting different techniques. In this study, we take inspiration from bone to design and manufacture new FRC (fiber-reinforced composite) materials inspired by the microstructure of cortical bone, with the aim of mimicking some toughening mechanisms and improving the toughness of conventional composites. We focus on the microstructural level, since the fundamental toughening mechanisms occur at the microscale, and we mimic the main features involved in the fracture process in our new design. The choice of the key features to be mimicked in the biomimetic material design process is guided by a previous experimental campaign performed on bovine cortical bone. Here we describe the design of a new bio-inspired material and an experimental campaign to assess the mechanical performance and the failure modes. The results of the tests allow us to confirm the promising mechanical characteristics of such material, compared to our previous design solutions and to similar classic structural composites (e.g. laminates). Moreover, the failure modes show many similarities with some of the toughening mechanisms occurring in cortical bone, confirming the key role, played by the mimicked bone-inspired microstructural features, in determining and enhancing the fracture toughness of the composites. © 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. 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.

* Corresponding author. Tel.: +30-02-2399-8667; fax: +39-02-2399-8263. E-mail address: flavia.libonati@polimi.it

* Corresponding author. Tel.: +351 218419991. E-mail address: amd@tecnico.ulisboa.pt * Corresponding author. Tel.: +30-02-2399-8667; fax: +39-02-2399-8263. E-mail address: flavia.libonati@polimi.it 2452-3216 © 2016 The Authors. Published by Elsevier B.V. Peer-review under responsibility of the Scientific Committee of ECF21.

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.2016.06.168 2452-3216 © 2016 The Authors. Published by Elsevier B.V. Peer-review under responsibility of the Scientific Committee of ECF21.