PSI - Issue 13

ScienceDirect Available online at www.sciencedirect.com Av ilable o line at www.sciencedire t.com cienceDirect Structural Integrity Procedia 00 (2016) 000 – 000 Procedia Structural Integrity 13 (2018) 1961–1966 Available online at www.sciencedirect.com ScienceDirect Structural Integrity Procedia 00 (2018) 000 – 000 Available online at www.sciencedirect.com ScienceDirect Structural Integrity 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. ECF22 - Loading and Environmental effects on Structural Integrity Correlation among Energy Based Fatigue Curves and Fatigue Design Approaches Bruno Atzori*, Mauro Ricotta, Giovanni Meneghetti a Department of Industrial Engineering, University of Padova, via Venezia, 1, 35131 Padova, Italy In this paper, with reference to the strain controlled fatigue characterization of AISI 304L stainless steel, the correlations between plain material fatigue curves based on different definitions of the strain energy densities, namely the elastic, plastic and elastoplastic strain energy densities evaluated under the cyclic stress-strain curve and the plastic strain hysteresis energy density (per cycle and total at fracture) are investigated. On this basis, a diagram showing the link among the different energy-based fatigue curves is proposed and is applied to find the correlation between plain material strain energy density fatigue curves and some fatigue strength assessment methods for notched structural components, namely the one based on the experimental evaluation of the heat energy dissipated by the material per cycle and the one based on the evaluation of the linear elastic strain energy density, averaged in a properly defined structural v lume. © 2018 The Authors. Published by Elsevier B.V. Peer-review under responsibility of the ECF22 organizers. Keywords: low-cycle fatigue, strain energy density, compatibility equations, Manson-Coffin curves, AISI 304L, fatigue design 1. Introduction Fatigue characterisation of metallic materials is usually expressed via equations that relate a damage variable with th number of cycles to failure. I classical approaches, fatigue life is given as a function of the stress amplitude or strain amplitude. According to a different approach, the strain energy density is adopted. Energy-based anal ses of fatigue damage wer first introduced appr ximately one century ago by Bairstow and have been subsequently formalised in different fashions by several authors. (see Klesnil and Lukas (1992), Ellyin (1997)). © 2018 The Authors. Published by Elsevier B.V. Peer-review under responsibility of the ECF22 organizers. ECF22 - Loading and Environmental effects on Structural Integrity Correlation among Energy Based Fatigue Curves and Fatigue Design Approaches Bruno Atzori*, Mauro Ricotta, Giovanni Meneghetti a Department of Industrial Engineering, University of Padova, via Venezia, 1, 35131 Padova, Italy Abstract In this paper, with reference to the strain controlled fatigue characterization of AISI 304L stainless steel, the correlations between plain material fatigue curves based o different definitions of the strain energy den ities, namely the elastic, plastic and el stoplastic strain en rgy d nsities evaluated under the cyclic stress-strain curv and the plastic strain hysteresis energy density (per cycle and total at fracture) are investigated. On this basis, a diagram showing the link among the diff rent energy-based fatigue curves is proposed and is applied to fin the correlation between plain material strain energy density fatigue curves an some fatigu strength assessment methods for not hed structural com onents, namely the one based on the xperimental evaluation of the heat energy dissipated by the material per cy le nd the one based on the evaluation of the linear elastic strain nergy density, aver g d in a properly efined structur l volume. © 2018 The Authors. Published by Elsevier B.V. Peer-review under responsibility of the ECF22 organizers. Keywords: low-cycle fatigue, strain energy density, compatibility equations, Manson-Coffin curves, AISI 304L, fatigue design 1. Introduction Fatigue characterisation of metallic materials is usually expressed via equations that relate a damage variable with the number of cyc es to failure. In classical approaches, fatigue life is given s a function of the stress amplitude or strain amplitude. According to a different approach, the strain energy de sity is adopted. Energy-based nalyses of fatigue damage were first intro uced approximately one century ago by Bairstow and have be n subsequently formalised in different fashions by several authors. (see Klesnil and Lukas (1992), Ellyin (1997)). © 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. Abstract

* Corresponding author. Tel.: +351 218419991. E-mail address: amd@tecnico.ulisboa.pt 2452-3216 © 2018 The Authors. Published by Elsevier B.V. Peer-review under responsibility of the ECF22 organizers. 2452-3216 © 2018 The Authors. Published by Elsevier B.V. Peer review under r sponsibility of the ECF22 organizers. * Corresponding author. Tel.: +39-049-827-6758; fax: +39-049-827-6785. E-mail address: bruno.atzori@unipd.it * Corresponding author. Tel.: +39-049-827-6758; fax: +39-049-827-6785. E-mail ad ress: bruno.atzori@unipd.it

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. Peer-review under responsibility of the ECF22 organizers. 10.1016/j.prostr.2018.12.264