PSI - Issue 13

ScienceDirect Available online at www.sciencedirect.com Available online at ww.sciencedire t.com ienceDirect Structural Integrity Procedia 00 (2016) 000 – 000 Procedia Structural Integrity 13 (2018) 1279–1284 Available online at www.sciencedirect.com ScienceDirect Structural Integrity Procedia 00 (2018) 000–000 Available online at www.sciencedirect.com ScienceDirect Structural I t 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. ECF22 - Loading and Environmental effects on Structural Integrity Multi-parameter average strain energy density factor criterion applied on the sharp material inclusion problem Ondřej Krepl a *, Jan Klusák a a CEITEC IPM, Institute of Physics of Material s AS CR, Žižkova 22, Brno 616 62, Czech Republic Abstract The tip of a sharp material inclusion (SMI) embedded in a parent material is considered as the singular stress concentrator. The SMI tip is modelled as a special case of a multi-material junction. The sin ular stress behaviour is caused by the material mismatch and geometrical discon inui y. The power of singularity is lower in comparison to th case of a crack. The stress field can be described by the asymptotic stress series, in which each term contains generalized stress intensity factor and stress terms exponent. The exponents are determined as a solution of eigenvalue problem. The factors are calculated by combination of analytical and numerical approaches. The terms can be either singular or non-singular depending on the stress term exponent. When approaching the concentrator, the singular terms become unbounded while the non-singular terms vanish. The non-singular terms increase precision of stress description on larger distances from the point of singularity. In some cases they provide the only means to describe the stress field well. Because of the singular stress behaviour near SMI tip, this location is prone to crack initiation. The crack initiation conditions are calculated by the average strain energy density factor (SEDF) criterion. Contrary to the cas of a crack, the direction of minimum of SEDF changes with dist nce from t e sing lar point. Therefore, an averaged value over specific dist nce is used. If the sp cific di tance is relatively larg , the employment of non- ingular ter s in multi-parameter criterion can significantly impro the critical pa amet rs prediction. Thanks to that .g. the particle composite des n can be optimized. © 2018 The Authors. Published by Elsevier B.V. Peer-review under responsibility of the ECF22 organizers. Keywords: Generalized fracture mechanics, Crack initiation, Sharp material inclusion, Stability criterion, Strain energy density factor; 1. Introduction – Stress distribution near sharp material inclusion A sharp material inclusion (SMI) belongs among general singular stress concentrators, and it can be modelled as the special case of multi-material junction. The stress concentrator of this kind can be found in particulate composite © 2018 The Authors. Published by Elsevier B.V. Peer-review under responsibility of the ECF22 organizers. ECF22 - Loading and Environmental effects on Structural Integrity Multi-parameter average strain energy density factor criterion applied on the sharp material inclusion problem Ondřej Krepl a *, Jan Klusák a a CEITEC IPM, Institute of Physics of Material s AS CR, Žižkova 22, Brno 616 62, Czech Republic Abstract The tip of a sharp material inclusion (SMI) embedded in a parent material is considered as the singular stress concentrator. The SMI tip is m d lled as a special case of a multi-mater al junction. he singular stress behav our is caused by the material mismatch and geometrical discontinuity. The power of singularity is lower in comparison to the case of a crack. The stress field can be described by the asymptotic stress series, in which each term contains generalized stress intensity factor and stress terms expone t. The exponents ar determined as a solution of eigenvalue problem. The factors are calculated by combination of analytical and numerical approaches. The terms can be either singular or non-singular depending on the stress term exponent. When approaching the concentrator, the singular terms become unbounded while the non-singular terms vanish. The non-singular terms increase precision of stress description o larger distances from the point of singularity. In some case they provide the o ly means to describe the stress field well. Because f the singular stress behaviour ear SMI tip, this location is prone to crack initiation. The crack initiation conditions are calculated by the avera e strain energy density f ctor (SEDF) criterion. Contrary to the case of a crack, the direction f mi imum of SEDF changes with d stance f om the singular poi t. Therefore, a averaged value ver specific dist nce is used. If the spec fic distance is relatively large, the employment of non-singular terms in multi-parameter cr terion can signific tly improve the criti al parameters pr diction. Thanks to that e.g. the particle composit design can be optimized. © 2018 The Authors. Published by Elsevier B.V. Peer-review under responsibility of the ECF22 organizers. Keywords: Generalized fracture mechanics, Crack initiation, Sharp material inclusion, Stability criterion, Strain energy density factor; 1. Introduction – Stress distribution near sharp material inclusion A sharp material inclusion (SMI) belongs among general singular stress concentrators, and it can be modelled as the special case of multi-materi l junction. The str ss concentrator of this kind can be found in particulate composite © 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.: +420532290338. E-mail address: krepl@ipm.cz * Corresponding author. Tel.: +420532290338. E-mail ad ress: krepl@ipm.cz

* 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 o ganizers.

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.2018.12.261