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) 137–142 Available online at www.sciencedirect.com Structural Integrity Procedia 00 (2018) 000–000 Available online at www.sciencedirect.com Structural Integrity 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 e ff ects on Structural Integrity Cutting resistance of polymeric materials: experimental and theoretical investigation A. Spagnoli a, ∗ , R. Brighenti a , M. Terzano a , F. Artoni a , P. Ståhle b a Department of Engineering and Architecture, University of Parma, Viale Usberti 181 / A, 43124 Parma, Italy b Division of Solid Mechanics, Lund University, SE-221 00 Lund, Sweden Abstract In the present paper, an experimental campaign is carried out with reference to the steady state propagation of an existing cut in polymeric plates, ranging from glassy to soft polymers. The steady state propagation is investigated by considering a commercial cutting tool under di ff erent insertion velocities of the blade. Full-field finite st ain maps are experimentally recorded by means of digital image correlation technique, along with the recording f the insertion force vs displacement curve. It is shown that the cutting resistance is dependent on the fracture toughness of the target material and on the sharpness of the cutting tool. Di ff erent scenarios of steady state cut propagation are observed if either a relatively blunt or a relatively sharp blade penetrates in the material. Alternative blade sharpness parameters can be used to discriminate the di ff erent conditions of cut propagation observed in the experiments. A theoretical interpretation of the experimental outcomes is provided. c 2018 The Authors. Published by Elsevier B.V. Peer-review under responsibility of the ECF22 organizers. Keywords: Cutting; oft materials; glassy polymers; large deformations; fractur toughness; blade sharpn s. 1. Introduction Separation of materials by means of a cutting tool is a commonplace process of several disciplines and applications (Atkins, 2009). Many cutting processes, such as chopping, slicing, carving, consist in two di ff erent stages: an initial stage of indentation, in which the cutting tool is pushed into the material under the action of an external force; and a second stage, where the target material undergoes a progressive separation under the tool advancement. This second stage is characterised by the formation of a fracture surface followed by the cut propagation due to the increasing external force, until eventually a cutting steady state might occur. In the present paper, an experimental campaign is carried out with reference to the steady state propagation of an existing cut in polymeric plates. The steady state propagation is investigated by considering di ff erent profiles of the cutting tool as well as di ff erent insertion velocities of the blade. Full-field finite strain maps are experimentally recorded by means of digital image correlation technique, along with the recording of the insertion force vs displacement curve. It is shown that the cutting resistance is depen- ECF22 - Loading and Environmental e ff ects on Structural Integrity Cutting resistance of polymeric materials: experimental and theoretical investigation A. Spagnoli a, ∗ , R. Brighenti a , M. Terzano a , F. Artoni a , P. Ståhle b a Department of Engineering and Architecture, University of Parma, Viale Usberti 181 / A, 43124 Parma, Italy b Division of Solid Mechanics, Lund University, SE-221 00 Lund, Sweden Abstract In the present paper, an experimental campaign is carried out with reference to the steady state propagation of an existing cut in polymeric plat s, anging from glassy to soft polymers. The steady state propagation is investigated by considering a commercial cutting tool under di ff erent insertion velocities of the blade. Full-field finite strain maps are experimentally recorded by means of digital image correlation technique, along with the recording of the insertion force vs displacement curve. It is shown that the cutting resistance is dependent on the fracture toughness of the target material and on the sharpness of the cutting tool. Di ff erent scenarios of steady state cut propagation are observed if either a relatively blunt or a relatively sharp blade penetrates in the material. Alternative blade sharpness parameters can be used to discriminate the di ff erent conditions of cut propagation observed in the experiments. A theoretical interpretation of the experimental outcomes is provided. c 2018 The Authors. Published by Elsevier B.V. r-review under responsibility of the ECF22 organizers. Keywords: Cutting; soft materials; glassy polymers; large deformations; fracture toughness; blade sharpness. 1. Introduction Separation of materials by means of a cutting tool is a commonplace process of several disciplines and applications (Atkins, 2009). Many cutting processes, such as chopping, slicing, carving, consist in two di ff erent stages: an initial stage of indentation, in which the cutting tool is pushed into the material under the action of an external force; and a second stage, where the target material undergoes a progressive separation under the tool advancement. This second stage is characterised by the formation of a fracture surface followed by the cut propagation due to the increasing external force, until eventually a cutting steady state might occur. In the present paper, an experimental campaign is carried out with reference to the steady state propagation of an existing cut in polymeric plates. The steady state propagation is investigated by considering di ff erent profiles of the cutting tool as well as di ff erent insertion velocities of the blade. Full-field finite strain maps are experimentally recorded by means of digital image correlation technique, along with the recording of the insertion force vs displacement curve. It is shown that the cutting resistance is depen- © 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.

2452-3216 © 2016 The Authors. Published by Elsevier B.V. Peer-review under responsibility of the Scientific Committee of PCF 2016. ∗ Corresponding author. Tel.: + 39-0521-905927 ; fax: + 39-0521-905924. E-mail address: spagnoli@unipr.it 2210-7843 c 2018 The Authors. Published by Elsevier B.V. Peer-review under responsibility of the ECF22 organizers. ∗ Corresponding author. Tel.: + 39-0521-905927 ; fax: + 39-0521-905924. E-mail address: spagnoli@unipr.it 2210-7843 c 2018 The Authors. Published by Elsevier B.V. Peer-revi w under responsibility of the ECF22 orga izers. * 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. 10.1016/j.prostr.2018.12.023