PSI - Issue 2_A

ScienceDirect Available online at www.sciencedirect.com Av ilable o line at ww.sciencedire t.com ienceDirect Structural Integrity Procedia 00 (2016) 000 – 000 Procedia Struc ural Integrity 2 (2016) 1619–1626 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 Cohesive model application to micro-crack nucleation and growth Jaroslaw Galkiewcz a, * a Kielce University of Technology, al. 1000-lecia PP 7, 25-314 Kielce, Poland Abstract The process of micro-crack nucleation and the first stages of micro-meso-crack propagation are analyzed with the help of a cohesive, finite element model. The loaded material cell containing an inclusion is presented. The model is based on experimental observations. The inclusion–matrix interface and planes of potential crack propagation in the inclusion and matrix are modeled with the cohesive elements implemented in ABAQUS. Both element-based and surface-based approaches are used. The material constants used in the calculations are hypothetical, but based on data relevant to the real materials and reported in the literature. The influence of the cohesive element parameters (that is, peak stress and fracture energy) as well as the influence of constr int on the sequence of events during loading of the material cell are analyzed. Relations between selected parameters of the model leading to inclusion fracture or the debonding process of an inclusion are established. © 2016 The Authors. Published by Elsevier B.V. Peer-review under responsibility of the Scientific Committee of ECF21. Keywords: finite element method; cohesive model; inclusion; debonding 1. Introduction Fractographic observations reveal modes of void nucleation. Homogeneous, strong inclusions debond from a matrix (Fig. 1a,b). In this case, debonding starts from the opposite points lying along a loading line. The load increase leads to the total debonding of an inclusion from a matrix and to the growth of a void (Fig. 1f). The void resembles a sphere irrespective of the initial shape of the inclusion. Weaker inclusions, especially those which are a conglomerate of several smaller inclusions, are prone to break (Fig. 1c,d). In this case, fractographic images reveal that the fracture of the inclusion had been the first stage of damage to a cell and then the debonding of the inclusion from the matrix took place while a new void was growing. g Copyright © 2016 The Authors. Published by Elsevier B.V. This is a open ac ess article under the CC BY-NC-ND license (http://creativec mmons.org/licens s/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.

* Corresponding author. Tel.: +48-41-34-24-711; fax: +48-41-34-24-295. E-mail address: jgalka@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 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.2016.06.205