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 Structural Integrity 13 (2018) 156 –1565 Available online at www.sciencedirect.com ScienceDirect Structural Integrity Procedia 00 (2018) 000 – 000 Available online at www.sciencedirect.com ScienceDirect 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 effects on Structural Integrity The Peak Stress Method Applied to Bi-Material Corners Mauro Ricotta a *, Michele Zappalorto b , Mattia Marchiori a , Alberto Campagnolo a , Giovanni Meneghetti a a Department of Industrial Engineering, University of Padova, via Venezia, 1, 35131 Padova, Italy b Department of Management and Engineering, University of Padova, Stradella San Nicola, 3, 36100 Vicenza, Italy Abstract Bi-material interfaces are unavoidably present in many engineering applications, such as microelectronics, adhesive joints, fiber reinforced composites and thermal barrier coatings. Under the hypothesis of linear elastic material behaviour, the local stress field at the point located at th free-edge of the bi-material interface has a singular behaviour, of which the intensity can be quantified by a generalized stress intensity factor, H. However, the numerical evaluation of H usually requires very accurate meshes and large computational efforts, hampering the use of H-based criteria in the engineering practice. The main aim of the present work is to overcome this limitation by extending to isotropic bi-material corners the Peak Stress Method (PSM), first proposed by Meneghetti and co-workers to estimate the stress intensity factor at the tip of a geometrical singular point with relatively coarse mesh patterns. © 2018 The Authors. Published by Elsevier B.V. Peer-review under responsibility of the ECF22 organizers. Keywords: bi-material corners, generalised stress intensity factor, Peak Stress Method 1. Introduction For several decades, scientists have put effort into the problem of finding stress distributions near points of singularity, basically with the aim to develop engineering strength criteria implicitly, or explicitly, based on local stress fields. In partic lar, the analysis of bi-material corners is a basic issue for the strength assessments of many engineering components, such as adhesive j ints, fib r-reinf rced composites and thermal barrier coatings. Within this context, worth of mention is the paper by Williams (1959), where the eigen-function expansion method was used to obtain an analytical solution for the stress fields in the neighborhood of a crack between dissimilar materials, and it was ECF22 - Loading and Environmental effects on Structural Integrity The Peak Stress Method Applied to Bi-Material Corners Mauro Ricotta a *, Michele Zappalorto b , Mattia Marchiori a , Alberto Campagnolo a , Giovanni Meneghetti a a Department of Industrial Engineering, University of Padova, via Venezia, 1, 35131 Padova, Italy b Department of Ma agement and Engine ring, University of Padova, Str della S n Nicola, 3, 36100 Vicenza, Italy Abstract Bi-material interfaces are unavoidably present in many engineering applications, such as microelectronics, adhesive joints, fiber reinforced composit nd thermal barrier coatings. Under the hypothesis of linear elastic material behaviour, the local stress field at the p int located at the free-edge of the bi-m terial interface has a singular behaviour, of which the intensity can be quantified by a generalized stress int sity fa tor, H. How ver, the numerical evaluation of H usually requires very accurate meshes and large computational fforts, hampering the use of H-bas d crit ria in the engi eering practice. The main aim of the present work is to overcome this limitation by xtending to isotropic bi-material corners the P ak Stress M thod (PSM), first proposed by Meneghetti and -workers to estimate the stress intensity factor at the tip of a g ometrical singular point with relatively coarse mesh patterns. © 2018 The Authors. Published by Elsevier B.V. Peer-review under responsibility of the ECF22 organizers. Keywords: bi-material corners, generalised stress intensity factor, Peak Stress Method 1. Introduction For several decades, scientists have put effort into the problem of finding stress distributions near points of singularity, basically with the aim to develop engineering strength criteria implicitly, or explicitly, based on local stress fields. In particular, the analysis of bi-material corners is a basic issue for the strength assessments of many engineering components, suc as adhesive joints, fiber-reinforced composites and thermal barrier coatings. Within this context, worth of mention is the paper by Williams (1959), where the eigen-function expansion method was used to obtain an analytical solution for the stress fields in the neighborhood of a crack between dissimilar materials, and it was © 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 o ganizers. * Corresponding author. Tel.: +39 049 827 6762; fax: +39 049 827 6785. E-mail address: mauro.ricotta@unipd.it * Corresponding author. Tel.: +39 049 827 6762; fax: +39 049 827 6785. E-mail ad ress: mau o.ricotta@unipd.it

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.2018.12.318