PSI - Issue 12

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 12 (2018) 37 –379 Available online at www.sciencedirect.com ScienceDirect Structural Integrity Procedia 00 (2018) 000 – 000 Available online at www.sciencedirect.com ScienceDirect 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. This is n ope access article under th CC BY-NC-ND licens (http://creativecommons.org/licenses/by-nc-nd/3.0/) Peer-revi w und r responsibility of the Scientific Commi tee of AIAS 2018 International Conferen e on St ess Analysis. AIAS 2018 International Conference on Stress Analysis 3D strip model for continuous roll-forming process simulation Luca Esposito a* , Alcide Bertocco a , Raffaele Sepe a , Enrico Armentani a a University of Naples Federico II, P.le V. Tecchio 80, 80125 Naples, Italy Abstract The paper addresses the complexities for a reliable numerical simulation of the roll forming process. During the process, the material is progressively bent accumulating plastic deformation at each forming step. Strain hardening limits the material formability and may causes flaws of the final shape. A simplified method for the FEM modeling of the process has been developed introducing a narrow-strip 3D model. This approach leads better performanc than the classical modeling method, in term of results reliability and low computational time. In order to verify the proposed model, an experimental campaign of testing, for a specific roll forming production process, was carried out. On the quasi-static regime, the post necking behavior of the sheet metal was characterized. The Vickers hardness and the plastic strain of uniaxial tests were empirically correlated. By the hardness correlation, the plastic strain accumulated at different stages of the process was evaluated and compared with the numerical results. Further possible improvements of the method are highlighted. © 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: Roll forming, FEM analysis, Strain-Hardness correlation * Corresponding author. Tel.: +39-0817682463; E-mail address: luca.esposito2@unina.it AIAS 2018 International Conference on Stress Analysis 3D strip model for continuous roll-forming process simulation Luca Esposito a* , Alcide Bertocco a , Raffaele Sepe a , Enrico Armentani a a University of Naples Federico II, P.le V. Tecchio 80, 80125 Naples, Italy Abstract The paper addresses the complexities for a reliable numerical simulation of the roll forming process. During the process, the material is progressively bent accumulating plastic deformation at each forming step. Strain hardening limits the material formability and may causes flaws of the final shape. A simplified method for the FEM modeling of the process has been developed introducing a narrow-strip 3D model. This approach leads bette performance than the classical modeling method, in terms of results reliability and low computational time. In order to verify the proposed mo el, an experimental camp ign of testing, for a specific roll forming production process, was carried out. On the quasi-static regime, the post necking behavior of the sheet metal was characterized. The Vickers hardness and the plastic strain of uniaxial tests were empirically correlated. By the hardness correlation, the plastic strain accumulated at different stages of the process was evaluated and compared with the numerical results. Further possible improvements of the method are highlighted. © 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: Roll forming, FEM analysis, Strain-Hardness correlation * Corresponding author. Tel.: +39-0817682463; E-mail address: luca.esposito2@unina.it

© 2016 The Authors. Published by Elsevier B.V. Peer-review under responsibility of the Scientific Committee of PCF 2016. 1. Introductio

1. Introduction

Keywords: High Pressure Turbine Blade; Creep; Finite Element Method; 3D Model; Simulation. Cold roll forming is a continuous deformation process to produce long shapes of essentially uniform cross-section starting from strip or coiled metal sheet. Generally, cold formed parts are forged in a number of stages and in each one the material is fed through multiple pairs of contoured forming rolls, which progressively shape the metal until the desired cross section is produced. To increase the machine durability oil-hardened tool steel is commonly used for Cold roll forming is a continuous deformation process to produce long shapes of essentially uniform cross-section starting from strip or coiled metal sheet. Generally, cold formed parts are forged in a number of stages and in each one the material is fed through multiple pairs of contoured forming rolls, which progressively shape the metal until the desired cross section is produced. To increase the machine durability oil-hardened tool steel is commonly used for

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-revi w u er responsibility of the Scientific Committee of AIAS 2018 International Conference on Stress Analysis. 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 u der responsibility of t Scientific ommittee of AIAS 2018 Internati al Conference on Stress Analysis.

* 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 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.2018.11.080