PSI - Issue 2_A

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 Struc ural Integrity 2 (2016) 1676–1683 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 Experimental determination of critical void volume fraction f F for the Gurson Tvergaard Needleman (GTN) model Wiktor Wcislik Kielce University of Technology, Al. 1000-lecia PP. 7, 25-314, Kielce, Poland Abstract The goal of the present study is the experimental determination of critical void volume fraction at the moment of failure ( f F ) in the GTN model. The experiment involved static tensile tests of notched specimens. The notch geometry allowed to obtain low stress state triaxiality ratio in the notch center, equal to 0.516. Fracture surfaces of the specimens used in tensile tests were then observed with the use of scanning electron microscope (SEM). Photographs obtained by SEM were subjected to image analysis procedure in order to extract areas representing voids in the picture and calculate their surface fraction as the fragment of the whole picture. Therefore, the void surface fraction in the picture was identified with the f F parameter. The procedure described above allowed to obtain f F = 0.598. The GTN model and the obtained f F parameter were used for the numerical simulation of static tensile test, providing good convergence with the experimental data. © 2016 The Authors. Published by Elsevier B.V. Peer-review under responsibility of the Scientific Committee of ECF21. Keywords: porous metal plasticity; voids; GTN model; numerical simulation 1. Introduction Metals used in civil engineering often crack due to initiation, growth and coalescence of voids. Most often voids are initiated around inclusions and precipitates by particle cracking or decohesion of the interface between the particle and adjacent matrix. As the plastic strain increases, initiated voids grow and coalesce, finally leading to macroscopic defect and failure of the structural element (Fig. 1). Thermal effects accompanying the process of plastic straining and ductile fracture can be monitored with the use of thermovision camera, Wcislik (2014 a). 21st European Conference on Fracture, ECF21, 20-24 June 2016, Catania, Italy Experimental determination of critical void volume fraction f F for the Gurson Tvergaard Needleman (GTN) model Wiktor Wcislik Kielce University of Technology, Al. 1000-lecia PP. 7, 25-314, Kielce, Poland Abstract The goal of the present study is the experimental determination of critical void volume fraction at the moment of failure ( f F ) in the GTN mod l. Th experiment involv d static tensile tests of not hed spec mens. The no ch geom try allowed to obtain low stress state triaxiality ratio in the notch center, equal to 0.516. Frac ur surfa es of the specimens used in tensil tests were then observed with the use of scanning electro microscope (SEM). Photographs obtained by SEM were subjected to image analysis procedure in ord r to extract areas r presenting voids in the picture and calcul te their surface f action as the fragm nt of the whole picture. Therefore, the void urfac fraction in the picture was identified wi h t f F par m ter. T e procedure described abo e allowed to obtai f F = 0.598. The GTN model and the obtained f F parameter were used for the nume cal simulation of static t nsile t st, pr vid g good co verg nce with th experimental data. © 2016 The A thors. Published by Elsevier B.V. Peer-review under espons bility of the Scientific Committee of ECF21. Keywords: porous metal plasticity; voids; GTN model; numerical simulation 1. Introduction Metals used in civil engineering often crack due to initiation, growth and coalescence of voids. Most often voids are initiated around nclu ons and pr cipitates by particle cracking or de hesion of the interface between the part cle n djacent matrix. As th plastic strain incr ases, initiated voi s grow and coalesce, inally leadi g to macroscopic efect and failure of the stru tu l elem nt (Fig. 1). Thermal effects ac mpanying the process of pl stic stra ning and ductile fracture can be monitored with the use of t er ovision camera, Wcisl k (2014 a). Copyright © 2016 The Aut ors. 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. © 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.

Tel.: +48 41 3424 436. E-mail address: wwcislik@tu.kielce.pl Tel.: +48 41 3424 436. E-mail address: wwcislik@tu.kielce.pl

* 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 responsibility of the Scientific Committee of ECF21.

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.2016.06.212