PSI - Issue 14

ScienceDirect Available online at www.sciencedirect.com Av ilable o line at ww.sciencedire t.com S ienceDirect Structural Integrity Procedia 00 (2016) 000 – 000 Procedia Structu al Integrity 14 (2019) 521–528 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. 2nd International Conference on Structural Integrity and Exhibition 2018 Determination and verification of triaxiality dependent cohesive zone parameters of SA333 Grade 6 steel Viswa Teja Vanapalli a,b* , J. Chattopadhyay a,b , Nevil Martin Jose b , B. K. Dutta a a Homi Bhabha National Institute, Anushaktinagar, Mumbai 400094, India b Re ctor Safety Division, Bhabha Atomic Research Centre, Trombay, Mumbai 40085, Indi Cohesive zone models are employed to simulate crack propagation in fracture process zone. It has been demonstrated in the presen study that the cohesive zone parameters depend not only on the material, but also on stress triaxiality. To determine cohesive zone parameters, experimental results of 14 three-point bend specimens (TPBB) made of SA333 Grade 6 steel were analyzed using 3D finite element model usi WARP3D. Cohesive param ters were determined by carrying out parame ric studies of thes specim n by varyi g peak stress ‘T’ to match experimental load -displacem nt data with the computed data. An exponential traction separation law was us d for this purpos . In addition, elastic-pl stic finite element analyses (FEA) are conducted to determine the multi- axiality quotient ‘q’ at the crack tip for TPBB specimens and pipe components. This helped to get a relation between peak stress ‘T’ and ‘q’. To extend the range of validity of parameter ‘T’ as a function of ‘q’, experi mental results of six piping components with through-wall circumferential crack made of SA333 Grade 6 steel tested earlier were also used similarly. A confidence interval band between q and T is then plotted to study the transferability of cohesive parameters. The variation in ‘T’ for the same value of ‘q’ is at tributed to the microstructural changes in the material near crack tip. To test the accuracy of the cohesive parameters determined above, experimental results of six piping components were again used. Using the ‘q’ parameters determined from elastic -plastic FEA on pipes, the upper and lower limits of peak stress ‘T’ from the confidence band determined above were found out. This range of ‘T’ was then used to carry out cohesive zone analyses (CZA) of these piping components to determine load-displacement curves. For each piping component, a set of load displacement curves were determined by assuming a normal variation of parameter ‘T’ over the maximum and minimum limits. The simulation results were compared with the experimental results and it has been observed that experimental results lie reasonably well within the computed results. 2nd International Conference on Structural Integrity and Exhibition 2018 Determinatio and verification of triaxialit dependent cohesive zone parameters of SA333 Grade 6 steel Viswa Teja Vanapalli a,b* , J. Chattopadhyay a,b , Nevil Martin Jose b , B. K. Dutta a a Homi Bhabha National Institute, Anushaktinagar, Mumbai 400094, India b Reactor Safety Division, Bhabha Atomic Research Centre, Trombay, Mumbai 40085, India Abstract Cohesive zone models are employed to simulate crack propagation in fracture process zone. It has been demonstrated in the pre ent study that the cohesive zone parameters depend not only on the material, but also on stress triaxiality. To determine cohesive zone parameters, experimental results of 14 three-point bend specimens (TPBB) made of SA333 Grade 6 steel were analyzed usi g 3D finite el ent model using WARP3D. Cohesive pa met rs were determined by carrying ou parame ric studies of hese specimens by varyi g e k str s ‘T’ to match experimental load -displacement da a with the compute data. An exponential traction separation law w s u ed f r this purpose. In a dition, ela tic-plastic finite element analyses (FEA) a conducted to determine the multi- axiality quotient ‘q’ at the crack tip for TPBB pecim n and pipe compone ts. This helped to get a rel tion between peak stress ‘T’ and ‘q’. To extend the range of validi y f ameter ‘T’ as a unction of ‘q’, exp ri me tal results of six pip ng compone ts with through-wall c rcumferential crack ma of SA333 Grade 6 st el tested earlier were also use similarly. A c nfidence in erval band between q and T is then pl tted to study the tra sferability of cohe ive param ters. The vari i n in ‘T’ for the same value of ‘q’ is at tributed to the microstructural ch nges in the material near crack tip. To te t the accuracy f the cohesive pa ameters dete mined above, experimental results of six piping components wer again . Us ng the ‘q’ paramet rs d termined from lastic -plastic FEA on pipes, the upper and lower l mits of peak stress ‘T’ from the confidence band de ermined above were found out. This range of ‘T’ was then used to carry out cohesive zone analyses (CZA) of these piping components to determin load-displacem nt curves. For each piping comp nent, a set of load displacement curves were d termined by assu ing a normal variation of arameter ‘T’ over the maximum and minimum limits. The simulation results were compared with the experimental results and it has been observed that exp rim ntal results lie reasonably w ll withi the comput d results. Keywords: Cohesive zone model; Multi- xiality quotient; Transferability of cohesive parameters. © 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. © 2019 The Authors. Published by Elsevier B.V. This is an open access article nder 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. Abstract

Keywords: Cohesive zone model; Multi-axiality quotient; Transferability of cohesive parameters.

* Corresponding author. Tel.: +91 22 2559 7548. E-mail address: viswateckie@gmail.com

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.2019.05.062 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 responsi ility 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 22 2559 7548. E-mail address: viswateckie@gmail.com