PSI - Issue 2_A

ScienceDirect Available online at www.sciencedirect.com Av ilable online at ww.sciencedire t.com ScienceDirect Structural Integrity Procedia 00 (2016) 000 – 000 Procedia Structu al Integrity 2 (2016) 793–80 Available online at www.sciencedirect.com Sci nceDirect Structural Integrity Procedia 00 (2016) 000–000 Available online at www.sciencedirect.com ScienceDirect Structural Integrity Procedia 00 (2016) 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. 21st European Conference on Fracture, ECF21, 20-24 June 2016, Catania, Italy Asymptotic Stress Field in the Vicinity of the Mixed-Mode Crack in Damaged Materials Under Creep Conditions Stepanova Larisa a *, Yakovleva Ekaterina a a Department of Mathematical Modelling in Mechanics, Samara State University,Akad. Pavlov, 1, 443011 Russia Abstract The creep crack problems in damaged materials under mixed mode loading under creep-damage coupled formulation are considered. The class of the self-similar solutions to the plane c eep crack problems in a damaged medium under mixed-mode loading is given. With the similarity variable and the self-similar representation of the solution for a power-law creeping material and the Kachanov- Rabotnov power-law damage evolution equation the near crack-tip stresses, creep strain rates and continuity distributions for plane stress conditions are obtained. The similarity solutions are based on the hypothesis of the existence of the completely damaged zone near the crack tip. It is shown that the asymptotical analysis of the near crack-tip fields gives rise to the nonlinear eigenvalue problems. The technique permitting to find all the eigenvalues numerically is proposed and numerical solutions of the nonlinear eigenvalue problems arising from the mixed-mode crack problems in a power-law medium under plane stress conditions are obtained. Using the approach developed the eigenvalues different from the eigenvalues corresponding to the Hutchinson-Rice-Rosengren (HRR) problem are found. Having obtained the eigenspectra and eigensolutions the geometry of the completely damaged zone in the vicinity of the crack tip is found for all values of the mixity parameter. © 2016 The Authors. Published by Elsevier B.V. Peer-review under responsibility of the Scientific Committee of ECF21. Keywords: Damage (integrity) parameter; similarity variable; self - similar solution; mixed-mode loading; creep-damage coupling; nonlinear eigenvalue problem; eigenvalue spectrum 21st European Conference on Fracture, ECF21, 20-24 June 2016, Catania, Italy Asymptotic Stress Field in the Vicinity of the Mixed-Mode Crack in Damaged Materials Under Creep Conditions Stepanova Larisa a *, Yakovleva Ekaterina a a Department of Mathematical Modelling in Mechanics, Samara State University,Akad. Pavlov, 1, 443011 Russia Abstract The creep crack problems in damaged materials under mixed mode loading under creep-damage coupled formulation are considered. The class of the self-similar solutions to th plane creep crack problems in a damaged medi m unde ixed-mod l ading is given. With the similarity variable and the self-similar presentation of the solution for a power-law cr eping material and the Kacha ov- Rabotnov power-l w dam ge evolution equation th near crack-tip stresses, cree strain rates and continu ty distributions for plane stress conditions are obtain d. The simil rity solutions a e based on th hypothesis of th existence of the completely damaged zon near the crack tip. It is shown that the as mpto cal nalysis of the near crack-tip fields gives ris to n nlin ar eigenvalue probl ms. The technique permitting to find all the eigenvalues numerically is proposed and numerical s lutio s of the nonlinear eigenvalu problems arising from he mixed-mode crack probl ms in a power-law me ium u der plane tress conditions are obtained. Using the approach devel ped the eigenvalues different from the eigenvalues corresponding to th Hutchinson-Rice-Rosengren (HRR) problem are found. Having obtai ed th eigenspect a and igensolutions the ge metry of completely damaged zone i the vicinity of the crack tip is found for all values of the mixity parameter. © 2016 The Authors. Published by Elsevier B.V. Peer-review under espons bility of the Scientific Committee of ECF21. Keywords: Damage (integrity) parameter; similarity variable; self - similar solution; mixed-mode loading; creep-damage coupling; nonlinear eigenvalue problem; eigenvalue spectrum Copyright © 2016 The Authors. Published by Elsevi r B.V. This i an open access ar icle under the CC BY-NC-ND license (http://cr ativecommons.org/licenses/by-nc-nd/4.0/). Peer-review under responsibility of the Scientific Comm ttee of ECF21.

© 2016 The Authors. Published by Elsevier B.V. Peer-review under responsibility of the Scientific Committee of PCF 2016. 1. Introduction

1. Introduction

Keywords: High Pressure Turbine Blade; Creep; Finite Element Method; 3D Model; Simulation. Knowledge of tress, strain nd dis lacement fields in the vicinity of the crack tip under mixed-mode loading conditions is important for the justif cation of fracture mec ani s criteria and has attracte considerable attent on Knowledge of stress, strain and displacement fields in the vicinity of the crack tip under mixed-mode loading conditions is important for the justification of fracture mechanics criteria and has attracted considerable attention

* 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 r sponsibility of the Scientific Committee of ECF21. * Stepanova Larisa. Tel.: +7 -846 -334-54-41; fax: +7-846-334-54-41. E-mail address: stepanovalv@samsu.ru * Stepanova Larisa. Tel.: +7 -846 -334-54-41; fax: +7-846-334-54-41. E-mail address: stepanovalv@samsu.ru

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.2016.06.102