PSI - Issue 2_A

ScienceDirect Available online at www.sciencedirect.com Av ilable o line at ww.sciencedire t.com Sci ceDirect Structural Integrity Procedia 00 (2016) 000 – 000 Procedia Structu al Integrity 2 (2016) 072– 79 Available online at www.sciencedirect.com Sci nceDirect 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 An elastic-interface model for the mixed-mode bending test under cyclic loads Stefano Bennati a , Paolo Fisicaro a , Paolo S. Valvo a * a University of Pisa, Department of Civil and Industrial Engineering, Largo Lucio Lazzarino, 56122 Pisa, Italy Abstract We have developed a mechanical model of the mixed-mode bending (MMB) test, whereby the specimen is considered as an assemblage of two identical sublaminates, modelled as Timoshenko beams. The sublaminates are partly connected by a linearly elastic–brittle interface, transmitting stresses along both the normal and tangential directions with respect to the interface plane. The model is described by a set of suitable differential equations and boundary conditions. Based on the explicit solution of this problem and following an approach already adopted to model buckling-driven delamination growth in fatigue, we analyse the response of the MMB test specimen under cyclic loads. Exploiting the available analytical solution, we apply a fracture mode dependent fatigue growth law. As a result, the number of cycles n eded for a delaminatio to extend to a giv n le th can be predicted. © 2016 The Authors. Published by Elsevier B.V. Peer-review under responsibility of the Scientific Committee of ECF21. Keywords: Composite laminate; delamination; fatigue; mixed-mode bending test; beam theory; elastic interface. 1. Introduction Composite laminates gen rall pr sent strongly orthotropic fracture properties under both quasi-static and cyclic loads. Several experimental pr cedures and testing s tups have been developed to determine the delamination toughness and to study fatigue behaviour of laminated specimens under pure and mixed fracture modes. Bak et al. (2014) have reviewed the available experimental observations, phenomenological models and computational simulation methods for delamination growth under fatigue loads in composite laminates. 21st European Conference on Fracture, ECF21, 20-24 June 2016, Catania, Italy An elastic-interface model for the mixed-mode bending test under cyclic loads Stefano Bennati a , Paolo Fisicaro a , Paolo S. Valvo a * a University of Pisa, Department of Civil and Industrial Engineering, Largo Lucio Lazzarino, 56122 Pisa, Italy Abstract We have developed a mechanical model of the mixed-mode bending (MMB) test, whereby the specimen is considered as an assemblage of two identical subl minat s, mod lled as Timoshenko beams. The sublaminates ar partly connected by a linearly elastic–brittle interfac , tr nsmitting str ses along both the normal and tangential directions with respect to the interface pl ne. The model is desc ibed by a set of suitable differential equati ns nd boundary con itions. Based on the explicit solution of this problem and following an pproach already adopted to model buckling-driven delamination growth in fatigue, we analyse the response of the MMB test s ecimen under cyclic loads. Exploiting the available analytical solution, we pply a fracture mode d pend nt fatigue growth law. As a result, the number of cycles needed for a delamination to extend to a given length can be predicted. © 2016 The Aut ors. Publish d by Elsevier B.V. Peer-review under espons bility of the Scientific Committee of ECF21. Keywords: Composite laminate; delamination; fatigue; mixed-mode bending test; beam theory; elastic interface. 1. Introduction Composite laminates generally present strongly orthotropic fracture properties under both quasi-static and cyclic loads. Several experimental procedur s and testing se ups have be n developed to determine the del mination t ughness and to study fatigue behaviour o laminated specimens under pur and mixe fractur modes. Bak e al. (2014) have reviewed the available experiment l observatio , ph nom nological models and computational simulation methods for delamin tion growth under fatigue lo ds in composite laminates. 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 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 ECF21. * Corresponding author. Tel.: +39-050-2218223; fax: +39-050-2218201. E-mail address: p.valvo@ing.unipi.it * Corresponding author. Tel.: +39-050-2218223; fax: +39-050-2218201. E-mail address: p.valvo@ing.unipi.it

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.2016.06.010