PSI - Issue 13

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 13 (2018) 285–291 Available online at www.sciencedirect.com ScienceDirect Structural Integrity Procedia 00 (2018) 000–000 Available online at www.sciencedirect.com ScienceDirect Structural Int grity 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. © 2018 The Authors. Published by Elsevier B.V. Peer-review under responsibility of the ECF22 organizers. ECF22 - Loading and Environmental effects on Structural Integrity Are the mechanical field parameters sufficient to predict uniquely the failure due to the ductile or cleavage mechanisms? Andrzej Neimitz a , Jaroslaw Galkiewicz a * Kielce University of Technology, Aleja Tysiaclecia Panstwa Polskiego 7, 25-314 Kielce, Poland Abstract The most often observed failure mechanisms in metallic alloys are divided in two groups: brittle and ductile. Brittle failure mechanism may proceed along grain boundaries (failure due to the creep process or aggressive environment) or along the cleavage planes within the grain. Ductile fracture mechanism is most often the result of voids nucleation–growth–coalescence process or by dislocation slip along slip planes. Tests were performed at three different temperatures: +20  C, –20  C, –50  C, on five different specimen geometries, designed to provide different stress triaxialities, Lode factors as well as critical strains and stresses at the moment of final failure. Numerical analyses were performed after careful calibration of the real stress – logarithmic strains uniaxial curve . Calibration followed modified Bai–Wierzbicki procedure. © 2018 The Authors. Published by Elsevier B.V. Peer-review under responsibility of the ECF22 organizers. Keywords: triaxiality; Lode angle; fracture mechanisms; stress-strain curve 1. Introduction In this paper the failur analysis of ferri ic steel, heat treated to r ceive three different microstructures is presented. The experiments were performed at three different temperatures of +20  C, –20  C and –50  C on five different specimens geometries. Both ductile and brittle failure mechanisms were observed, preceded by extensive plastic deformation. The analysis of these mechanisms was carried on within the scope of the isotropic continuum mechanics of solids. It is believed that the normal (to fracture surface) stress tensor component is responsible for brittle (cleavage) micro, meso, macro – crack extension [1–3] when it is greater than the critical value over the distance (area) also greater than the ECF22 - Loading and Environmental effects on Structural Integrity Are the mechanical field parameters sufficient to predict uniquely the failure due to the ductile or cleavage mechanisms? Andrzej Neimitz a , Jaroslaw Galkiewicz a * Kielce University of Technology, Aleja Tysiaclecia Panstwa Polskiego 7, 25-314 Kielce, Poland Abstract The most often observed failure mechanisms in metallic alloys are divided in two groups: brittle and ductile. Brittle failure mechanism may proceed along grain bou daries (failure due to the cr ep process or aggressive environment) or along the cle vage planes within the grain. Ductile fracture mechanism is most often the result of voids nucleation–growth–coalescence process or by dislocation slip along slip planes. Tests were performed at th ee different temperatures: +20  C, –20  C, –50  C on five different specimen geometries, designed to provide different stress triaxialities, Lod factors as well as critical strains and stresses at the moment of final failure. Num rical analys s were performed after careful calibr ti n of the real stress – logarithmic strains uniaxial curves. Calibr tion followed modified Bai–Wierzbicki procedure. © 2018 The Authors. Published by Elsevier B.V. Peer-review under responsibility of the ECF22 organizers. Keywords: triaxiality; Lode angle; fracture mechanisms; stress-strain curve 1. Introduction In this paper th f ilure a alysis of ferritic steel, heat treated to receive three different microstructur s is pres nted. The experiments were performed at three different temperatures of +20  C, –20  C and –50  C on five different specimens geometries. Both ductile and brittle failure mechanis s were observed, preceded by extensive plastic deformation. The analysis of these mechanisms was carried on within the scope of the isotropic continuum mechanics of solids. It is believed that the normal (to fracture surface) stress tensor component is responsible for brittle (cleavage) micro, meso, macro – crack extension [1–3] when it is greater than the critical value over the distance (area) also greater than the © 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.: +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.: +48-41-342-4711; fax: +48-41-342-4295. E-mail address: jgalka@tu.kielce.pl * Corresponding author. Tel.: +48-41-342-4711; fax: +48-41-342-4295. E-mail ad ress: jgalka@tu.kielce.pl

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.2018.12.048