PSI - Issue 13

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 Structu al Integrity 13 (2018) 155–16 Available online at www.sciencedirect.com Structural Integrity Procedia 0 (2018) 0– 0 Available online at www.sciencedirect.com 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. © 2018 The Authors. Published by Elsevier B.V. Peer-review under responsibility of the ECF22 organizers. ECF22 - Loading and Environmental e ff ects on Structural Integrity Application of material forces and path independent integrals to the prediction of crack initiation and crack paths Paul Judt a , Andreas Ricoeur a a Institute of Mechanics, University of Kassel, Mo¨nchebergstraße 7, 34125 Kassel, Germany Abstract Next to the shape of a growing crack, it is of importance to predict the initiation of new cracks, especially in structures with stress concentrations due to e.g. holes or notches. In the past, di ff erent criteria for crack initiation have been discussed. Furthermore, cracks growing in the vicinity of such stress concentrations in general are deflected and therefore complex crack paths arise. The prediction of crack initiation and the shape of crack paths becomes even more complicated if a material exhibits anisotropic constitutive properties or fracture toughnesses. In this paper, a unified approach of material forces for the prediction of the initiation and growth of a crack is presented. The material or configurational forces as crack driving quantity are strongly related to path-independent integrals, e.g. the J k -integral. A novel methodology is presented for accurately calculating material forces at cracks employing local numerical data. Material tractions at a round U-notch are investigated and related to crack initiation. c 2018 The Authors. Published by Elsevier B.V. Peer-review under responsibility of the ECF22 organizers. Keywords: mat ial forces, accur cy, crack initiation, crack paths, fracture toughness anisotropy 1. Introduction In many engineering applications, the safety-critical function of structures must be verified. One important exami nation in such structures is the assessment of initiation and growth of cracks. In general, cracks emanate at regions of stress concentrations such as holes, notches or inclusions. Whitney and Nuismer [21] presented an approach based on the maximum principle stresses to predict the initiation of cracks. The finite fracture mechanics approach (FFM) [11] combines a stress and energy based prediction of crack initiation and was recently applied to several boundary value problems [17, 20, 19]. To meet the stress and energy criteria in FFM, an analytical solution of the problem must be known in advance or a vast numerical e ff ort is necessary to obtain the crack initiation position, angle and length. To predict the loading situation at cracks, loading quantities such as stress intensity factors (SIF), energy release rate (ERR) G or J -integral are typically employed in linear elastic fracture mechanics (LEFM). Di ff erent methods ECF22 - Loading and Environmental e ff ects on Structural Integrity Application of aterial forces and path independent integrals to the prediction of crack initiation and crack paths Paul Judt a , Andreas Ricoeur a a Institute of Mechanics, University of Kassel, Mo¨nc ebergstraße 7, 34125 Kassel, Germany Abstract Next to the shape of a growing crack, it is of importance to predict the initiation of new cracks, especially in structures with stress concentrations due to e.g. holes or notches. In the past, di ff erent criteria for crack initiation have been discussed. Furthermore, cracks growing in the vicinity of such stress concentrations in general are deflected and therefore complex crack paths arise. The prediction of crack initiation and the shape of crack paths becomes even more complicated if a material exhibits anisotropic constitutive properties or fracture tough esses. In this paper, a unified approach of material forces for the prediction of the initiation and growth of a crack is presented. The material or configurational forces as crack driving quantity are strongly related to path-independent integrals, e.g. the J k -integral. A novel methodology is presented for accurately calculating material forces at cracks employing local numerical data. Material tractions at a round U-notch are investigated and related to crack initiation. c 018 The Authors. Published by Elsevier B.V. r ie unde responsibility of the ECF22 organizers. Keywords: material forces, accuracy, crack initiation, crack paths, fracture toughness anisotropy 1. Introduction In many engineering applications, the safety-critical function of structures must be verified. One important exami nation in such structures is the assessment of initiation and growth of cracks. In general, cracks emanate at regions of stress concentrations such as holes, notches or inclusions. Whitney and Nuismer [21] presented an approach based on the maximum principle stresses to predict the initiation of cracks. The finite fracture mechanics approach (FFM) [11] combines a stress and energy bas d pr diction of crack initiation and was rece tly applied to several boundary value problems [17, 20, 19]. To meet the stress and energy criteria in FFM, an analytical solution of the problem must be known in advance or a vast numerical e ff ort is necessary to obtain the crack initiation position, angle and length. To predict the loading situation at cracks, loading quantities such as stress intensity factors (SIF), energy release rate (ERR) G or J -integral are typically employed in linear elastic fracture mechanics (LEFM). Di ff erent methods © 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.

2452-3216 © 2016 The Authors. Published by Elsevier B.V. Peer-review under responsibility of the Scientific Committee of PCF 2016. 2210-7843 c 2018 The Authors. Published by Elsevier B.V. Peer-review under responsibility of the ECF22 organizers. 2210-7843 c 2018 The Authors. Published by Elsevier B.V. Peer-review under responsibility of the ECF22 organizers. * Corresponding author. Tel.: +351 218419991. E-mail address: amd@tecnico.ulisboa.pt ∗ Corresponding author. Tel.: + 49-561-804-2852; fax: + 49-451-804-2720. E-mail address: j dt@uni-kassel.de ∗ Corresponding author. Tel.: + 49-561-804-2852; fax: + 49-451-804-2720. E-mail address: judt@uni-kassel.de 2452-3216  2018 The Authors. Published by Elsevier B.V. Peer-review under responsibility of the ECF22 organizers. 10.1016/j.prostr.2018.12.026