PSI - Issue 12

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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 Elsevie B.V. Thi is an open access article nder the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/3.0/) Peer-review under r sponsibility of the Scientific Committee of AIAS 2018 I erna ional Conference on Stress Analysis. AIAS 2018 International Conference on Stress Analysis Bio-inspired solution for optimal adhesive performance A. Papangelo ∗ a,b a Politecnico di BARI. Department of Mechanics Mathematics and Management, Viale Japigia 182, 70126 Bari, Italy b Hamburg University of Technology, Department of Mechanical Engineering, Am Schwarzenberg-Campus 1, 21073 Hamburg, G rmany Abstract In recent years there has been a growing interest into high performance bioinspired adhesives. This communication focuses on the adhesive behavior of a rigid cylinder that indents an elastic layer coated on a rigid substrate. With the assumption of short range adhesive interactions (JKR type) the adhesive solution is obtained very easily starting from the adhesiveless one. We show that ultrastrong adhesion (up to theoretical material strength) can be reached in line contact by reducing the thickness of the layer, typically down to the nanoscale size, which suggests a new possible design for ”optimal adhesion”. Adhe i n enhancement occurs as an increase of the actual pull-o ff force, which is further enhanced by Poisson’s ratio e ff ects in the case of nearly incompressible layer. The system studied could be an interesting geometry for an adhesive system, but also a limit case of the more general class of layered systems, or FGMs (Functionally Graded Materials). The model is well suited for analyzing the behavior of polymer layers coated on metallic substrates. c 2018 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 / 3.0 / ) Peer-review under responsibility of the Scientific Committee of AIAS 2018 International Conference on Stress Analysis. Keywords: Adhesion; layer; JKR model; Adhesion enhancement; 1. Introduction Adhesion is a very flourishing field in contact mechanics. Even if big steps forward have been undertaken, a lot remains to do. The fundamental solution of an adhesive sphere indenting an halfspace has been discussed long time ago leading to the very known solutions of JKR (Johnson et al., (1971)) and DMT (Derjaguin et al., (1975)), which, after Tabor (1977) paper, have been understood as the limit solutions for very soft (JKR) and very hard (DMT) contacting bodies. The situation for rough contact is instead much less clear and a big e ff ort has been put by many researchers to unveil how rough contact behaves (Pastewka & Robbins (2014), Persson & Scaraggi, (2014), Joe et al. (2018), Ciavarella et al. (2017), Ciavarella & Papangelo (2018a), Ciavarella & Papangelo (2018b)). In the last decade many researchers have developed models and designed surfaces trying to imitate nature adhesive strategies, AIAS 2018 International Conference on Stress Analysis Bio-inspired solution for opti al adhesive perfor ance A. Papangelo ∗ a,b a Politecnico di BARI. Department of Mechanics Mathematics and Management, Viale Japigia 182, 70126 Bari, Italy b Hamburg University of Technology, Department of Mechanical Engineering, Am Schwarzenberg-Campus 1, 21073 Hamburg, Germany Abstract In recent years there has been a growing interest into high performance bioinspired adhesives. This communication focuses on the adhesive behavior of a rigid cylinder that indents an elastic layer coated on a rigid substrate. With the assumption of short range adhesive interactions (JKR type) the adhesive solution is ob ained very easily starting from the adhesiveless one. We show that ultrastrong adhesion (up to theoretical material strength) can be reached in line contact by reducing the thickness of the layer, typically down to the nanoscale size, which suggests a new possible design for ”optimal adhesion”. Adhesion enhancement occurs as an increase of the actual pull-o ff force, which is further enhanced by Poisson’s ratio e ff ects in the case of nearly incompressible layer. The system studied could be an interesting geometry for an adhesive system, but also a limit case of the more general class of layered systems, or FGMs (Functionally Graded Materials). The model is well suited for analyzing the behavior of polymer layers coated on metallic substrates. c 2018 The Authors. Published by Elsevier B.V. is is an open access article under the CC BY-NC-ND license (http: // creativecommons.org / licenses / by-nc-nd / 3.0 / ) r-review unde responsibility of the Scientific Committee of AIAS 2018 International Co fer nce on Stress Analysis. Keywords: Adhesion; layer; JKR model; Adhesion enhancement; 1. Introduction Adhesion is a very flourishing field in contact mechanics. Even if big steps forward have been undertaken, a lot remains to do. The fundamental solution of an adhesive sphere indenting an halfspace has been discussed long time ago leading to the very known solutions of JKR (Johnson et al., (1971)) and DMT (Derjaguin et al., (1975)), which, after Tabor (1977) paper, have been unders ood as th limit solutions for very soft (JKR) and very hard (DMT) contacting bodies. The situation for rough contact is instead much less clear and a big e ff ort has been put by many researchers to unveil how rough contact behaves (Pastewka & Robbins (2014), Persson & Scaraggi, (2014), Joe et al. (2018), Ciavarella et al. (2017), Ciavarella & Papangelo (2018a), Ciavarella & Papangelo (2018b)). In the last decade many researchers have developed models and designed surfaces trying to imitate nature adhesive strategies, © 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 ∗ Corresponding author. Tel.: + 39-080-596-2718 E-mail address: antonio.papangelo@poliba.it ∗ Corresponding author. Tel.: + 39-080-596-2718 E-mail address: antonio.papangelo@poliba.it

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. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/3.0/) Peer-review under responsibility of the Scientific Committee of AIAS 2018 International Conference on Stress Analysis. 10.1016/j.prostr.2018.11.089 2210-7843 c 2018 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 / 3.0 / ) Peer-review under responsibility of the Scientific Committee of AIAS 2018 International Conference on Stress Analysis. 2210-7843 c 2018 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 / 3.0 / ) Peer-review under r ponsibility of the Scientific ommitt e of AIAS 2018 International Conference on Stress Analysis.