PSI - Issue 14

ScienceDirect Available online at www.sciencedirect.com Av ilable o line at www.sciencedire t.com ScienceDirect Structural Integrity Procedia 00 (2016) 000 – 000 Procedia Structu al Integrity 14 (2019) 668–675 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 Modelling of Fatigue Crack Initiation in Hydrogen Charged Polycrystalline Nick l Rakesh Kumar a , Deepesh Meena a , Dhiraj K. Mahajan a * a Ropar Mechanics of Material Laboratory, Department of Mechanical Engineering, Indian Institute of Technology Ropar, Rupnagar, 140001, India Abstract Hydrogen Embrittlement (HE) leads to deterioration of the fracto-mechanical properties of metals. In spite of vast literature, it is still not clearly understood and demands significant research on this topic. For better understanding of the hydrogen effect on fatigue behaviour of metals, present work focuses on developing a computational framework for fatigue crack initiation studies in metals in the presence f hydrogen. The developed framework co sists of a nonlocal crystal plast city model coupled with hydrogen transport model to study the fatigue behaviour of hydrogen charged metals. The nonlocal crystal plasticity model accounts for the statistically stored dislocations (SSDs) and geometrically necessary dislocations (GNDs) in polycrytalline metal. Hydrogen transport model, on the other hand, accounts for diffusion and trapping behavior of hydrogen due to concentration gradient, pressure gradient, plastic strain-rate with dislocations as the only trapping sites along the slip systems. A polycrystalline representative volume element (RVE) with periodic boundary conditions is used in this study. Fatigue crack initiation criterion is proposed for the simulated RVE with controlled micr structure by considering a cr ti al value of the fatigue indicator parameter (FIP). FIP is formulated bas d on th experimental observations f several crack ini ia ion sites along the grain boundaries, their normal irection with respect to loading direction and the accumulated plastic strain in nickel po ycrystalline sampl s. D velop d simulation framew rk correctly accounts cyclic stress-strain behavior and multiple fatigue crack initi tion sit s observed experime tally in the presence of hyd ogen. © 2018 The Authors. Published by Elsevier B.V. This is an open a cess article und r the CC BY-NC-ND licens (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 Modelling of Fatigue Crack Initiation in Hydrogen Charged Polycrystalline Nickel Rakesh Kumar a , Deepesh Meena a , Dhiraj K. Mahajan a * a Ropar Mechanics of Material Laboratory, Department of Mechanical Engineering, Indian Institute of Technology Ropar, Rupnagar, 140001, India Abstract Hydrogen Embrittlement (HE) leads to deterioratio of the fracto-mechan al p op r ies of me ls. In spite of vast literatur , it is still not cle rly understood and demands significa t r s arch on this topic. For better understand ng of the hydroge effect o fatigue behaviour of m tals, present work focus s on develo ing a mputation l framework for fatigue crack initiation stu ies in metals i he resence of hydrogen. The dev loped framework consists of a nonlocal crystal plasticity mode coupled with hydrogen t ansport mode to stu y the fatigue behaviour of hydrogen charged meta s. The nonlocal crysta plastic ty odel accounts fo the statistical y stored dislocations (SSDs) and geometrically necessary dislocations (GNDs) i polycrytalline metal. Hy rogen transport model, on he other hand, accounts f r diffusion and tra ping beh vior of hydrogen due to con en rat on gradient, pressure gradient, plastic strain-rate with disl cations as the ly trapping sites along the slip systems. A p ly rystalline representa ive v lu e el ment (RVE) with periodic b undary conditions is used in this study. Fatigue crack initiatio criterion is proposed for the simulated RVE with cont olled microst uc ure by considering a cr cal valu of the fatigue dica or paramete (FIP). FIP s f rmulated based on the expe imental obs rvations of several crack itiation sites along the grain boundaries, th ir norm l direction w th espect to lo ding dire tion nd the accumulated plastic strain n nickel polycrystalline samples. Develop simulatio fram work correctly accounts cyclic stress-str in behavior and multiple fatigue crack initiation sites observe exp rimentally in the presence of hydrogen. © 2018 The Author . Published by Elsevi r B.V. This is an open access rticle und r 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.

© 2016 The Authors. Published by Elsevier B.V. Peer-review under responsibility of the Scientific Committee of PCF 2016. Keywords: Nonlocal cry tal plasticity; h drog n transport model; fatigue crack initiation; fatigue indicator parameter. Keywords: Nonlocal crystal plasticity; hydrogen transport model; fatigue crack initiation; fatigue indicator parameter.

Keywords: High Pressure Turbine Blade; Creep; Finite Element Method; 3D Model; Simulation.

* Corresponding author. Tel.: +91-1881-242244; E-mail address: dhiraj.mahajan@iitrpr.ac.in * Correspon ing author. Tel.: +91-1881-242244; E-mail address: dhiraj.mahajan@iitrpr.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.2019.05.083