PSI - Issue 7

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ScienceDirect Available online at www.sciencedirect.com Av ilable o line at ww.sciencedire t.com ScienceDirect Structural Integrity Procedia 00 (2016) 000 – 000 Procedia Structu al Integrity 7 (2017) 53 –535 Available online at www.sciencedirect.com ScienceDirect Structural Integrity Procedia 00 (2017) 000–000 Structural Integrity Procedia 00 (2017) 000–000

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www.elsevier.com/locate/procedia 3rd International Symposium on Fatigue Design and Material Defects, FDMD 2017, 19-22 September 2017, Lecco, Italy Competition between surface defect and grain size under fatigue loading - ARMCO iron Y. Nadot * , C. Nadot-Martin, A. Dragon and M. Vincent 3rd International Symposium on Fatigue Design and Material Defects, FDMD 2017, 19-22 September 2017, Lecco, Italy Competition betw en surface defect and grain size under fatigue loading - ARMCO iron Y. Nadot * , C. Nadot-Martin, A. Dragon and M. Vincent 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. Copyright © 2017 The Authors. Published by El evier B.V. Peer-review und r responsibility of the Scientific Committe of th 3rd International Symposium on Fatigue Design and Material Defects. Institut Pprime, ISAE-ENSMA, CNRS, Université de Poitiers, Téléport 2, 1 Avenue Clément Ader, BP40109, 86961 Futuroscope Chasseneuil Cedex, France Abstract The design of metallic cast parts requires a compromise between the f tigue resistance of the component and the allowable defect size due to the process. Treatment of defect sensitivity coupled with intrinsic length scal s of grains or other microstructure attributes is ultimately necessary to form a predictive basis for defect size effects in forming and growing small defect cracks. This work presents experimental results on high cycle fatigue behavior of specimens containing a surface hemispherical defect under uniaxial tension loading for a wide range of notch size to grain size ratios, including cases where the notch size is on the order of, or even smaller, than the grain size. The influence of grain size on the fatigue strength is clearly demonstrated and the corresponding effects are evaluated. This paper shows that for the same specimen geometry, loading conditions and defect morphology, the fatigue limit is directly dependent on the relationship between the defect size and the grain size. Dimensionless Kitagawa diagram shows that the defect size which impacts the fatigue limit is greater than 0.7 times the grain size in the Armco iron and greater than three times the grain size in other steels. © 2017 The Authors. Published by Elsevier B.V. Institut Pprime, ISAE-ENSMA, CNRS, Université de Poitiers, Téléport 2, 1 Avenue Clément Ader, BP40109, 86961 Futuroscope Chasseneuil Cedex, France Abstract The design of metallic cast parts requires a compromise between the fatigue resistance of the component and the allowable defect size due to the process. Treatment of defect sensitivity coupled with intrinsic length scales of grains or other microstructure attributes is ultimately necessary to form a predictive basis for defect size effects in forming and growing small defect cracks. This work presents experimental results on high cycle fatigue behavior of specimens containing a surface hemispherical defect under uniaxial tension loading for a wide range of notch size to grain size ratios, including cases where the notch size is on the or r of, or even smaller, than the grain size. The fluence of grain size on the fatigue strength is cl arly demonstrated and the corresponding ffects are evaluated. This paper shows that for the same specim n geomet y, loading conditions and d fect morphology, the fatigue limit is directly dependent on the rel ionship b tween the defect size and the grain size. Dimensionless Kitagawa diagram shows that the defect size which impact the fatigue limit is gr ater than 0.7 times the grain size in the Armco iron and greater th n t ree times t grain size in other steels.

© 2016 The Authors. Published by Elsevier B.V. Peer-review under responsibility of the Scientific Committee of PCF 2016. © 2017 The Authors. Published by Elsevier B.V. Keywords: High Pressure Turbine Blade; Creep; Finite Element Method; 3D Model; Simulation. * Corresponding author. Tel.: +33-54949804. E-mail address: yves.nadot@ensma.fr

* Corresponding author. Tel.: +33-54949804. E-mail address: yves.nadot@ensma.fr

2452-3216 © 2017 The Authors. Published by Elsevier B.V. Peer-review under responsibility of the Scientific Committee of the 3rd International Symposium on Fatigue Design and Material Defects. 2452-3216 © 2017 The Authors. Published by Elsevier B.V. Peer-review under responsibility of the Scientific Committee of the 3rd International Symposium on Fatigue Design and Material Defects.

* 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 Copyright  2017 The Authors. Published by Elsevier B.V. Peer-review under responsibility of the Scientific Committee of the 3rd International Symposium on Fatigue Design and Material Defects. 10.1016/j.prostr.2017.11.122