PSI - Issue 12

ScienceDirect Available online at www.sciencedirect.com Av ilable o line at www.sciencedire t.com ienceDirect Structural Integrity Procedia 00 (2016) 000 – 000 Procedia Structu al Integrity 12 (2018) 499–5 6 Available online at www.sciencedirect.com ScienceDirect Structural Integrity Procedia 00 (2018) 000 – 000 Available online at www.sciencedirect.com ScienceDirect Structural Int grity 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. AIAS 2018 International Conference on Stress Analysis Multi-axial fatigue numerical crack propagation in cruciform specimens Venanzio Giannella*, Renato Esposito a Dept. of Industrial Engineering, University of Salerno, via Giovanni Paolo II, Fisciano (SA), Italy Two cracks, initiated from the opposite tips of a 45° inclined central notch, were considered in cruciform specimens made of Ti6246. A static load was applied along an arm of the cruciform specimen together with an alternating load (R=-1) applied long the ot er arm. Experimen al results were available from literature all wing a validation of the numerical procedure adopted to calculate the crack propagation paths and crack growth rates monitored during such tests. In particular, numerical evaluations by means of the Dual Boundary Element Method (DBEM) were performed, using the Minimum Strain Energy Density (MSED) criterion for the crack path assessment and J-integral approach for SIFs evaluations. Allowance for non-linear contact with friction was provided for those load cases in which contact between the crack faces occurred. Crack growth rates were predicted by using the Walker law, previously calibrated using the set of data coming from the first tested specimen. A good agreement between experimental and numerical crack paths was obtained. It was found that the cracks propagate without appreciable kinking, on the initial notch plane, for static loads lower than 10-15% of ynamic load amplitude, whereas the cracks develop perpendicul r to the static load direction when the latt r exceeds 25% of the dynamic loa amplitude. Both propagation paths and crack growth rates were provide as a function of the static t dy amic lo d ratio. © 2018 The Authors. Published by Elsevier B.V. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/3.0/) Peer-review under responsibility of the Scientific Committee of AIAS 2018 International Conference on Stress Analysis. © 2018 The Authors. Published by Elsevier B.V. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/3.0/) Peer-review under responsibility of the Scientific Committee of AIAS 2018 International Conference on Stress Analysis. AIAS 2018 International Conference on Stress Analysis Multi-axial fatigue numerical crack propagation in cruciform specimens Venanzio Giannella*, Renato Esposito a Dept. of Industrial Engineering, University of Salerno, via Giovanni Paolo II, Fisciano (SA), Italy Abstract Two cracks, initiated from the opposite tips of a 45° inclined central notch, were considered in cruciform specimens made of Ti6246. A static load was applied along an arm of the cruciform specimen together with an alternating load (R=-1) applied along the other arm. Experimental results were available from literature allo ing a validation of the numerical procedure adopted to calculate the crack propagation paths and crack growth rates monitored during such tests. In particular, numerical evaluations by means of the Dual Boundary Element Method (DBEM) were performed, using the Minimum Strain Energy Density (MSED) criterion for the crack path assessment and J-integral approach for SIFs evaluations. Allowance for non-linear contact with friction was provided for those load cases in which contact between the crack faces occurred. Crack growth rates ere predicted by using the Walker law, previously calibrated using the set of data coming from the first tested specimen. A good agreeme t between experimental and numerical crack p ths was obtained. It was found th t the cracks propag te without appreciable kinking, on the initial notch plane, for static loads lower than 10-15% of dynamic load a pli ude, whereas the cracks d velop pe pendicu ar to the static load direction when the latter exceeds 25% of the dynamic lo d amplitude. Both propagation paths and crack growth rates were provided as a function of the static to dynamic load ratio. © 2018 The Authors. Published by Elsevier B.V. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/3.0/) Peer-review under responsibility of the Scientific Committee of AIAS 2018 International Conference on Stress Analysis. Abstract

© 2016 The Authors. Published by Elsevier B.V. Peer-review under responsibility of the Scientific Committee of PCF 2016. Keywords: Cruciform specimen, HCF, Multiple cracks, DBEM, crack path. Keywords: Cruciform specimen, HCF, Multiple cracks, DBEM, crack path.

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

* Corresponding author. Tel.: +39-089-96-4111; fax: +39-089-96-4111. E-mail address: vgiannella@unisa.it * Corresponding author. Tel.: +39-089-96-4111; fax: +39-089-96-4111. E-mail address: vgiannella@unisa.it

2452-3216 © 2018 The Authors. Published by Elsevier B.V. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/3.0/) Peer-revi w u er responsibility of the Scientific Committee of AIAS 2018 International Conference on Stress Analysis. 2452-3216 © 2018 The Authors. Published by Elsevier B.V. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/3.0/) Peer-review u der responsibility of t Scientific ommitt e of AIAS 2018 Internati al Conference on Stress Analysis.

* 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  2018 The Authors. Published by Elsevier B.V. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/3.0/) Peer-review under responsibility of the Scientific Committee of AIAS 2018 International Conference on Stress Analysis. 10.1016/j.prostr.2018.11.068