PSI - Issue 2_B

ScienceDirect Available online at www.sciencedirect.com Av ilable o line at ww.sciencedire t.com cienceDirect Structural Integrity Procedia 00 (2016) 000 – 000 Procedia Structu al Integrity 2 (2016) 919–926 Available online at www.sciencedirect.com ScienceDirect Structural Integrity Procedia 00 (2016) 000–000

www.elsevier.com/locate/procedia

www.elsevier.com/locate/procedia

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. 21st European Conference on Fracture, ECF21, 20-24 June 2016, Catania, Italy Type IV creep cracking of welded joints: numerical study of the grain size effect in HAZ L. Esposito a * a DII, University of Naples “Federico II”, p.le V. Tecchio 80, 80125 Napoli, Italy Abstract A reliable creep design for very long lives, capable to account for both diffusion and dislocation mechanisms, was used to explain the onset of type IV fracture in weldments. An unexpected decreased creep rupture strength at low stress is the typical consequence of this failure. The fine-g ained heat affected zone (FGHAZ) is the most sensitive region to the type IV failure. In this paper the effect of the grain size distribution was numerically investigated. The creep rupture occurs at the FGHAZ as a result of localized creep strain accumulation supported by high stress triaxiality which is known to promote nucleation and growth of cavities and reduce the material ductility. The stress triaxiality is mostly related to the grain size gradient in HAZ, thus an optimized grain size distribution could result in a longer creep life of the joints. © 2016 The Authors. Published by Elsevier B.V. Peer-review under responsibility of the Scientific Committee of ECF21. Keywords: Type IV fracture; creep of welded joints. 1. Background Type IV fracture is the typical failure mechanism of welded joints which operate under creep conditions. It occurs preferentially in the over-tempered, intercritical or refined region of the heat affected zone (HAZ). This mechanism is the main cause of lacking performance of 9 and 12 wt-% chromium steels for high temperature applications, Francis et al. (2006). The fine-grained heat affected zone (FGHAZ) is the region most sensitive to the Copyright © 2016 The Aut ors. Published by Elsevier B.V. This is an op n access article under the CC BY-NC-ND licens (http:// ativecommons. rg/licenses/by-nc-nd/4.0/). Peer-review und responsibility of the Scientific Co mittee of ECF21. © 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.: +39 081 7682463. E-mail address: luca.esposito2@unina.it

* 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 ECF21.

2452-3216 © 2016 The Authors. Published by Elsevier B.V. Peer-review under responsibility of the Scientific Committee of PCF 2016. Copyright © 2016 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/4.0/ ). Peer review under responsibility of the Scientific Committee of ECF21. 10.1016/j.prostr.2016.06.118