PSI - Issue 14

ScienceDirect Available online at www.sciencedirect.com Av ilable o line at www.sciencedire t.com Sci ceDirect Structural Integrity Procedia 00 (2016) 000 – 000 Procedia Structu al Integrity 14 (2019) 684–687 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 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. 2nd International Conference on Structural Integrity and Exhibition 2018 A new semi-analytical approach for obtaining crack-tip stress distributions under variable-amplitude loading A.N. Savkin a , D.S. Denisevich a *, K.A. Badikov a , A.A. Sedov a a Volgograd State Technical University, Lenin Avenue 28, Volgograd 400005, Russian Federation Abstract Near threshold fatigue crack response is extremely sensitive to load history. It is associated with the influence of near-tip stress on instantaneous resistance of crack tip surface layers to failure under atmospheric conditions. The paper deals with computational aspects of stress and strain distributions at the crack tip. A new approach is proposed to obtain near-tip stress under variable amplitude loading. The method considers a combination of standard rules for determining local strains (Linear rule, Neuber rule, ESED method, etc.) and well-known in Finite Element Analysis (FEA) return mapping algorithm in context of nonlinear mixed hardening material model. Iterative procedure based on Newton-Raphson method is proposed to calculate plastic variables and near-tip stress at each load step. The calculated results obtained by new model are validated with the traditional approach in case of Al2024-T3 alloy for constant amplitude loading after tensile/c mprehensive ov rloa s. © 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: crack growth rate, crack closure, cyclic plastic zone, stress intensity factor, threshold stress intensity, variable-amplitude loading, plasticity, back-stress, kinematic hardening; 2nd International Conference on Structural Integrity and Exhibition 2018 A new semi-analytical approach for obtaining crack-tip stress distributions under variable-amplitude loading A.N. Savkin , D.S. Denisevich a *, K.A. Badikov a , A.A. Sedov a a Volgograd State Technical University, Lenin Avenue 28, Volgograd 400005, Russian Federation Abstract Near threshold fatigue cra k response is extremely sensitive t load history. It is as ociated with the influence of near-tip stress on ins nta eou re istance of crack tip su face layers to failure under atmospheric conditions. The paper deals with comput tional spec s of stress and strain distributions at the crack tip. A new pproach is proposed to obtain ne r-tip str ss under variable amplitude loading. The method considers a combination of standard rules fo determi ing l cal strains (Linear rule, Neuber rule, ESED method, etc.) and w ll-known in Finite Eleme t Analysis (FEA) return map ing algorithm in context of nonlinear mixed hardening m erial m del. Iterativ pro edure ba ed on Newton-Raphson method is proposed to calculate plastic variables and n ar-tip stress at ach l ad step. The alculat d results o ain by new mode are vali ated with he traditional approa h in case of Al2024-T3 alloy for constant amplitude load ng after t nsile/comprehe sive verloads. © 2018 The Authors. Published by Elsevier B.V. This is a open access article under the CC BY-NC-ND license (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. Keywords: crack growth rate, crack closure, cyclic plastic zone, stress intensity factor, threshold stress intensity, variable-amplitude loading, plasticity, back-stress, kinematic hardening;

© 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.: +7927-535-1068. E-mail address: denisevich@vstu.ru * Correspon ing author. Tel.: +7927-535-1068. E-mail address: denisevich@vstu.ru

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.2019.05.085