PSI - Issue 14

ScienceDirect Available online at www.sciencedirect.com Av ilable o line at www.sciencedire t.com cienceDirect Structural Integrity Procedia 00 (2016) 000 – 000 Procedia Structu al Integrity 14 (2019) 619–626 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. © 2019 The Authors. Published y Elsevier B.V. This is an open access article under the CC BY-NC-ND license (https://creativecommons.org/li enses/by- c-nd/4.0/) Selec ion and pe r-review under responsibility of Peer-review under responsibility of the SICE 2018 organiz rs. 2nd International Conference on Structural Integrity and Exhibition 2018 Cyclic mean stress relaxation behaviour of P91 steel: Experiments and onstitutive modeling Bimal Das a , Akhilendra Singh a * a Department of Mechanical Engineering, Indian Institute of Technology Patna, 801103, India Abstract In the present study effe t of mea strain on cyclic plastic deformatio charact ristics f P91 steel is experimentally evaluated and compared with results of finite element simulation considering cyclic plasticity models. P91 steels being used in various components in fossil fired and nuclear power plants are subjected to cyclic loading with mean strains/stresses. Symmetrical and asymmetrical strain controlled tests of P91 steel conducted at room temperature revealed cyclic softening nature during the fatigue cycling process. The influence of mean strain imposed showed strong dependence on stress relaxation behavior and fatigue life of P91 steel. Tensile mean stress was found to relax steeply in initial cycles followed by stabilization during the asymmetric strain cycling. A reduction in fatigue life is observed with increase in mean strain for particular strain amplitude. An attempt has also been made to simulate asymmetric strain controlled behavior of P91 steel through cyclic plastic modeling in the framework of rate independent plasticity theory. Ohno-Wang material model is employed to predict the influence of mean strain on stress relaxation behavior of the investigated steel. The simulated results depicted that Ohno-Wang model captures the cyclic plastic deformation behavior of P91 steel reasonably well. © 2018 The Authors. Published by Elsevier B.V. This is an open access article under the CC BY-NC-ND license (https://creativecommons.org/licenses/by-nc-nd/4.0/) Selection and peer-review under responsibility of Peer-review under responsibility of the SICE 2018 organizers. Keywords: Fatigue life; cyclic softening; stress relaxation; Ohno-Wang. 2nd International Conference on Structural Integrity and Exhibition 2018 Cyclic mean stress relaxation behaviour of P91 steel: Experiments and constitutive modeling Bimal Das a , Akhilendra Singh a * a Department of Mechanical Engineering, Indian Institute of Technology Patna, 801103, India Abstract I the present study ffect f mean strain on cyclic plastic defo mation characteris ics f P91 steel is exper mentally evaluated and c mpared with results of finit element simulation consid ring pl sticity models. P91 steels b ing used in v rious components in fossil fired and nuclear power plants are subjected t cyclic loading with mean strains/s resses. Symmetrical and asymmetri al strain controlled tests of P91 steel conducted at oom temperature r vealed cyclic softening nature dur ng the cycling process. he influence of mean train impos d showed strong depend nce on stress rel xation behav or and fatigue life of P91 steel. Tensile mean stress was found to r lax s eeply in initial cycles foll wed by stabilization during the sy metric strain cycling. A reduction in fatigue life is observed with increase in mean strain for particular strain amp tude. An atte pt has also been made to simulate asymmetric strain controll d behavior of P91 st el through cyclic p asti modeling in the framework of rate independent plast city heory. Ohno-Wang material model is employed to predict the influence of mean strain on ress relax av or f the inv stigated steel. The simulated results depicted that Ohno-Wang model captures the cyclic plastic deformation behavior of P91 steel reasonably well. © 2018 The Authors. Published by Elsevier B.V. This is an open access article und r the CC BY-NC-ND lic nse (https://creativecommons.org/licenses/by- c-nd/4.0/) Selection and peer-review under responsibility of Peer-review under responsibility of the SICE 2018 organizers. Keywords: Fatigue life; cyclic softening; stress relaxation; Ohno-Wang.

© 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.: +91-612-3028018; fax: +91-612-2277383. E-mail address: akhil@iitp.ac.in * Correspon ing aut or. Tel.: +91-612-3028018; fax: +91-612-2277383. E-mail address: akhil@iitp.ac.in

2452-3216 © 2018 The Authors. Published by Elsevier B.V. This is an open access article under the CC BY-NC-ND license (https://creativecommons.org/licenses/by-nc-nd/4.0/) Selection and peer-review under responsibility of Peer-review under responsibility of the SICE 2018 organizers. 2452-3216 © 2018 The Authors. Published by Elsevier B.V. This is a open access article und r the CC BY-NC-ND lic nse (https://creat vecommons.org/licenses/by- c-nd/4.0/) Selection and peer-review under responsibility of Peer-review under responsibility of the SICE 2018 organizers.

* 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  2019 The Authors. Published by Elsevier B.V. This is an open access article under the CC BY-NC-ND license (https://creativecommons.org/licenses/by-nc-nd/4.0/) Selection and peer-review under responsibility of Peer-review under responsibility of the SICE 2018 organizers. 10.1016/j.prostr.2019.05.076