PSI - Issue 13

ScienceDirect Available online at www.sciencedirect.com Av ilable o line at ww.sciencedire t.com ScienceDirect Structural Integrity Procedia 00 (2016) 000 – 000 Procedia Structu al Integrity 13 (2018) 976–981 Available online at www.sciencedirect.com ScienceDirect Structural Integrity Procedia 00 (2018) 000 – 000 Available online at www.sciencedirect.com ScienceDirect Structural Int grity Procedia 00 (2018) 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. © 2018 The Authors. Published by Elsevier B.V. Peer-review under responsibility of the ECF22 organizers. ECF22 - Loading and Environmental effects on Structural Integrity Fracture of brittle materials under uniaxial compression Mina Iskander a *, Nigel Shrive b a PhD Candidate, University of Calgary, Calgary, AB, T2N 1N4, Canada b Professor, University of Calgary, Calgary, AB, T2N 1N4, Canada Abstract Fracture under compressive loading is distinctly different compared to fracture under tensile loading. One contributing factor is that interatomic bonds have to be stretched to be broken: compressing the interatomic spacing cannot break an interatomic bond. This is demonstrated by the fact that no fracture occurs in materials loaded in hydrostatic compression, even at extreme magnitudes. It is believed that fracture in compressive stress fields starts due t loca tensile stresses which develop around a discontinuity (e.g. an air bubble). A 2D numerical study is conducted to study the effect of the shape and size of such a discontinuity on crack propagation in a macroscopic uniaxial compressive stress field. The results of this study highlight the major differences between tensile crack propagation and compressive crack propagation in brittle solids. © 2018 The Authors. Published by Elsevier B.V. Peer-review under responsibility of the ECF22 organizers. Keywords: Compression; Uniaxial; Crack propagation; Fracture; Brittle 1. Introduction Brittle materials can be defined as materials that r spond to applied loads pproximately linearly until the load is high enough to cause fracture and consequently total failure. The interesting thing about brittle materials is that they fail totally differently according to the type of applied load; whether it is causing compression or tension. If the applied load causes tension, the interatomic/intermolecular bonds are stretched and, consequently, break when the maximum bond strength is reached as discussed by Van Vlack (1989). Failure is typically caused by the propagation of a single crack. In contrast, loads causing compression of the interatomic/intermolecular bonds will never break them – only ECF22 - Loading and Environmental effects on Structural Integrity Fracture of brittle materials under uniaxial compression Mina Iskander a *, Nigel Shrive b a PhD Candidate, University of Calgary, Calgary, AB, T2N 1N4, Canada b Professor, University of Calg ry, Calg ry, AB, T2N 1 4, Can d Abstract Fracture under compressive loading is distinctly different compared to fracture under tensile loading. One contributing factor is th t int ratomic bonds have to be stretched to be broken: compressing the interatomic spacing cannot break an interatomic bond. This is demonstrated by the fact that no fracture occurs in materials loaded in hydrostatic compressio , even at extreme magnitudes. It is beli ved that f acture in compressive str ss fields starts due to l al tensile stresses which develop around a discontinuity (e.g. an air bubble). A 2D numerical study is conducte to stu y the effect of the shap and size of such a discontinuity on crack propagation in a macroscopic uniaxial compressiv stress field. The results of this study highlight the m jor differences between tensile crack propagation and compressive crack propagation in brittle solids. © 2018 The Authors. Published by Elsevier B.V. Peer-review under responsibility of the ECF22 organizers. Keywords: Compression; Uniaxial; Crack propagation; Fracture; Brittle 1. Introduction Britt e materials c n be defined as materials that respond to applied oads approximately lin ar y until the load is high enough to cause fracture and consequently total failure. The interesting thing about brittle materials is that they fail totally differently according to the type of applied load; whether it is causing compression or tension. If the applied load causes tension, the interatomic/intermolecular bonds are stretched and, consequently, break when the maximum bond strength is reached as discussed by Van Vlack (1989). Failure is typically caused by the propagation of a single crack. In contrast, loads causing compression of the interatomic/intermolecular bonds will never break them – only © 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.: +1-587-500-2995 E-mail address: mina.iskander@ucalgary.ca * Corresponding author. Tel.: +1-587-500-2995 E-mail ad ress: mina iskander@ucalgary.ca

* Corresponding author. Tel.: +351 218419991. E-mail address: amd@tecnico.ulisboa.pt 2452-3216 © 2018 The Authors. Published by Elsevier B.V. Peer-review under responsibility of the ECF22 organizers. 2452-3216 © 2018 The Authors. Published by Elsevier B.V. Peer review under r sponsibility of the ECF22 o ganizers.

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

2452-3216  2018 The Authors. Published by Elsevier B.V. Peer-review under responsibility of the ECF22 organizers. 10.1016/j.prostr.2018.12.182