PSI - Issue 7

ScienceDirect Available online at www.sciencedirect.com Av ilable o line at ww.sciencedirect.com ienceDirect Structural Integrity Procedia 00 (2016) 000 – 000 Procedia Structu al Integrity 7 (2017) 229–234 ScienceDirect Structural Integrity Procedia 00 (2017) 000–000 Available online at www.sciencedirect.com ScienceDirect 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 Hardness as a tool for the estimation of the microstructural threshold Mirco D. Chapetti * INTEMA, Research Institute for Materials Science and Technology CONICET – University of Mar del Plata. Colón 10850 (7600) Mar del Plata, Argentina Abstract As it was described by K. Miller, fatigue resistance can be characterized by the existence of a microstructural and a mechanical threshold. The microstructural threshold is strictly related to the intrinsic microstructural properties of the material and it can be defined as the stress level needed for a microstructurally short crack (MSC) to overcome the strongest microstructural barrier, usually found to be a characteristic microstructural dimension d (grain size, pearlite colony size, bainite lath length, etc). Previous work by Chapetti provided vidence that this intrinsic thresh ld stress level m tches the material’s plain fatigue limit at a distance d from the surface. In this work, hardness is evaluated as a parameter to be included in the estimation of the microstructural threshold associated to the plain fatigue limit of metals. The proposed expression seems to work reasonably well for low and medium strength (ferritic-pearlitic and martensitic) steels and load ratio R = -1. 3rd International Symposium on Fatigue Design and Material Defects, FDMD 2017, 19-22 September 2017, Lecco, Italy Hardness as a tool for the estimation of the microstructural threshold Mirco D. Chapetti * INTEMA, Research Institute for Materials Science and Technology CONICET – University of Mar del Plata. Colón 10850 (7600) Mar del Plata, Argentina Abstract As it was descri ed by K. Miller, fat gue resistance can be characterized by the existence of a microstructural and a mechanical threshold. The microstructural thr shold is st ctly elated to the intri sic microstructural properties of the material and it can e efined as the stress level n eded for a microstructurally short c ack (MSC) to ov come the strongest microstructural barrier, usually found to be a char cteristic microstructural dim nsion d (grain size, pearlite colony size, bainite lath length, etc). Previous work by Chapetti provided eviden e that this intrinsic threshold tress level matches the material’s plain fatigue limit at a distance d from the surface. In this work, hardness is evaluated as a parameter to be included in the estimation of the microstructural threshold associated to the plain fatigue limit of metals. The proposed expression seems to work reasonably well for low and medium strength (fer itic-pearlitic and martensitic) steels and load rati R = -1. 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 Elsevier B.V. Peer-review under responsibility of the Scientific Committee of the 3rd International Symposium on Fatigue Design and Material Defects. © 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. Keywords: Hardness; Plain Fatigue Limit; Microstructural Fatigue Threshold; Estimation © 2017 The Authors. Published by Elsevier B.V. P er-review under responsibility of he S ientific Committee of t e 3rd International Symposium on Fatigue Design and Material Defects. Keywords: Hardness; Plain Fatigue Limit; Microstructural Fatigue Threshold; Estimation

© 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. * Correspondin author. Tel.: +39-0532-974843. E-mail address: mchapetti@fi.mdp.edu.ar

* Corresponding author. Tel.: +39-0532-974843. E-mail address: mchapetti@fi.mdp.edu.ar

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.2017.11.082