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) 442–448 Available online at www.sciencedirect.com ScienceDirect Structur lIntegrity Procedi 00 (2018) 000 – 000 Available online at www.sciencedirect.com Scie ceDirect StructuralIntegrity 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 Structural Integrity Assessment of a Propellant tank in Presence of Welding Residual Stresses V. Viswanath a *, A.K. Asraff b , Jayesh.P c , Suresh Mathew Thomas d , Krishnakumar R e , Muthukumar. R f a Deputy Head, Fatigue & Fracture Studies Division, SMAG/ SDAG, MDA/ LPSC, ISRO, Valiamala, Thiruvananthapuram, 695547, India b Group Director, Structural Dynamics & Analysis Group, MDA/ LPSC, ISRO, Valiamala, Thiruvananthapuram, 695547, India c Scientist/ Engineer, Earth Storable Tankages Design Division, ESTDG/ MDA/ LPSC, ISRO,Valiamala, Thiruvananthapuram, 695547, India d Group Head,Structural Mechanics & Analysis Group, MDA/ LPSC/ ISRO, Valiamala, Thiruvananthapuram, 695547, India e Group Director, Earth storable Structures & T nkages Design Group, MDA/ LPSC/ ISRO, Valiamala, Thiruvananthapuram, 695547, India f Deputy Director, Mechanical Design & Analysis Entity, LPSC/ ISRO, Valiamala, Thiruvananthapuram, 695547, India Abstract Upper stage of India’s new generation launch vehicle makes use of cryogenic propellants with liquid hydrogen (LH2) and liquid oxygen (LOX) as fuel and oxidizer respectively. The propellants are stored in tanks fabricated of Aluminum alloy and contain various openings. As carrying out proof test at operating environment is not feasible, the tanks are subjected to proof pressure test at room temperature (RT). During the RT proof pressure test of LOX tank, high strains, greater than 8000  , were recorded by gauges at three locations where weld rework had been undertaken. From structural analysis, the maximum welding residual stress at these locations is evaluated to be 95N/mm 2 . From stress analysis point of view, positiv margins wer observed with resp ct t failure of the tank ev n in presence of these residual stresses. However, since the tank is operating at cryogenic temperature, though there is an increase in the yield and ultimate strengths of the tank material, there is a reduction in ductility (lower percentage elongation). Therefore, evaluation of structural integrity of the hardware from fracture point of view is of paramount importance. A study was undertaken to investigate the influence of residual stresses on integrity of the tank in presence of minimum detectable crack sizes using conventional NDE techniques. The location where maximum strains were observed, post proof test, is considered for fracture evaluation. Directional stresses at location of interest are predicted through detailed finite element analysis. Subsequently, generalized Failure Assessment Diagram was drawn based on Elasto-Plastic fracture mechanics principles and margin against ultimate load ensured. The tank was used in a launch vehicle which was successfully flown in June 2017. © 2018 he Authors. Published by lsevier . . This is an open access article under the - - license (https://creativecom ons.org/licenses/by-nc-nd/4.0/) Selection and peer-revie under responsibility of Peer-revie under responsibility of the SI 2018 organizers. 2nd International Conference on Structural Integrity and Exhibition 2018 Structural Integrity Assessment of a Propellant tank in Presence of Welding Residual Stresses V. Viswanath a *, A.K. Asraff b , Jayesh.P c , S resh Mathew Thomas d , Krishnakumar R e , Muthukumar. R f a Deputy Head, Fatigue & Fracture Studies Division, SMAG/ SDAG, MDA/ LPSC, ISRO, Valiamala, Thiruvananthapuram, 695547, India b Group Director, Structural Dynamics & Analysis Group, MDA/ LPSC, ISRO, Valiamala, Thiruvananthapuram, 695547, India c Scientist/ Engineer, Earth Storable Tankages Design Division, ESTDG/ MDA/ LPSC, ISRO,Valiamala, Thiruvananthapuram, 695547, India d Group Head,Structural Mechanics & Analysis Group, MDA/ LPSC/ ISRO, Valiamala, Thiruvananthapuram, 695547, India e Group Director, Eart storable Structures & Tankages Design Group, MDA/ LPSC/ ISRO, Valiamala, Thiruvananthapuram, 695547, India f Deputy Director, Mechanical Design & Analysis Entity, LPSC/ ISRO, Valiamala, Thiruvananthapuram, 695547, India Abstract Upper stage of India’s new generation launch vehicle makes use of cryogenic propellants with liquid hydrogen (LH2) and liquid oxygen (LOX) as fuel and oxidizer respectively. The propellants are stored in tanks fabricated of Aluminum alloy and contain various openings. As carrying out proof test at operating environment is not feasible, the tanks are subjected to proof pressure test at room temperature (RT). During the RT proof pressure test of LOX tank, high strains, greater than 8000  , were recorded by gauges at three locations where weld rework had been undertaken. From structural analysis, the maximum welding residual stress at these locations is evaluated to be 95N/mm 2 . From stress analysis point of view, positive margins were observed with respect to failure of the tank even in presence of these residual stresses. However, since the tank is operating at cryogenic temperature, though there is an increase in the yield and ultimate strengths of the tank material, there is a reduction in ducti ity (lower percen ge el ngation). Therefore, valuation of s ructural integrity of the ha dware from fracture point of view is of paramount importance. A study was undertaken to investigate the influence of residual stresses on in egrity of the tank in presence of minimum detectable crack sizes using conventional NDE techniques. The location where maximu strains were obs rved, post proof test, is considered for fracture evaluation. Directional stresses at location of interest are predicted through detailed finite element analysis. Subsequently, generalized Failure Assessment Diagram was drawn based on Elasto-Plastic fracture mechanics principles and margin against ultimate load ensured. The tank was used in a launch vehicle which was successfully flown in June 2017. © 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. © 2016 The Authors. Published by Elsevier B.V. Peer-review under responsibility of the Scientific Committee of PCF 2016. Keywords: Residual stress; Failure Asessment Diagram; Elasto-Plastic Fracture Mechanics; Proof test Keywords: Residual stress; Failure Asessment Diag am; Elasto-Plastic Fracture Mechanics; Proof test Keywords: High Pressure Turbine Blade; Creep; Finite Element Method; 3D Model; Simulation.

* Corresponding author. Tel.: +91-471-256-7826; fax: +91-471-256-7791. E-mail address: v_viswanath@lpsc.gov.in

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.2019.05.054 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 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. * Corresponding author. Tel.: +351 218419991. E-mail address: amd@tecnico.ulisboa.pt * Corresponding author. Tel.: +91-471-256-7826; fax: +91-471-256-7791. E-mail address: v_viswanath@lpsc.gov.in