PSI - Issue 13

ScienceDirect Available online at www.sciencedirect.com Av ilable o line at ww.sciencedire t.com cienceDirect Structural Integrity Procedia 00 (2016) 000 – 000 Procedia Structu al Integrity 13 (2018) 793–798 Available online at www.sciencedirect.com Structural Integrity Procedia 00 (2018) 000–000 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 Structures with bridged cracks and weak interfaces Mikhail Perelmuter ∗ Ishlinsky Institute for Problems in Mechanics RAS, Vernadsky avenue, 101-1, Moscow, 119526, Russia Abstract Structures with interfacial bridged cracks and weak interfaces are analyzed. In the frames of this approach is assumed that: a) the crack surfaces interact in some zones behind the crack tips (bridged zones); b) size of these zones can be comparable to the whole crack length; and c) the interface between di ff erent materials can be connected by mechanical ligaments and a relative displacement of initially adja ent materials may occur (non-ideal or weak i terface). S veral new pr blems for interface bridged cracks and interaction of bridged cracks with material interface were solved and analyzed by the direct boundary integral equations method. c ⃝ 2018 The Authors. Published by Elsevier B.V. Peer-review under responsibility of the ECF22 organizers. Keywords: interfacial cracks; crack bridged zone; weak interface; boundary elements 1. Introduction Analysis of cracks growth in composite materials and in adhesive joints using models of a crack process zone (cohesive or bridged) includes the problem of displacements and stresses computation in crack process zones and in vicinity of the crack tips. In this paper the bridged crack approach will be considered as a crack process zone model. In this approach it is assumed that the stress intensity factors do not vanish at the cr ck tip. The problems of displacements and stresses analysis for bridged cracks have mainly considered for straight cracks in infinite homogeneous media. For bridged interfacial cracks between two semi-infinite homogeneous plates the problems were considered and solved firstly in (Goldstein and Perelmuter, 1999) by the singular integral-di ff erential equations method (planar problem). Similar problem (but without analysis of stresses at the bridged zone) was considered for anisotropic materials in (Ni and Nemat-Nasser, 2000). In the last two decades a number of papers were devoted to the application of the boundary integral equation (BIE) method to computation of the stress intensity factors for cracks on bi-material interfaces in finite size structures. In these papers interaction between crack surfaces was neither assumed nor considered, see review in (Hadjesfandiari and Dargush, 2011). Only few papers have been directed to analysis of straight bridged cracks in finite size structures. The extension of BIE approach for solving elasticity problems for curvilinear interfacial crack has been proposed and numerically implemented in (Perelmuter, 2013). ECF22 - Loading and Environmental e ff ects on Structural Integrity Structures with bridged cracks and weak interfaces Mikhail Perelmuter ∗ Ishlinsky Institute for Problems in Mechanics RAS, Vernadsky avenue, 101-1, Moscow, 119526, Russia Abstract Structures with interfacial bridged cracks and weak interfaces are analyzed. In the frames of this approach is assumed that: a) the crack surfaces interact in some zones behind the crack tips (bridged zones); b) size of these zones can be comparable to the whole crack length; and c) the interfac between di ff er nt mater als can be conn cted by mechanical l gaments and a rel tive displacement of initially adjacent materials may occur (non-ideal or weak interface). Several new problems for interface bridged cracks and interaction of bridged cracks with material interface were solved and analyzed by the direct boundary integral equations method. c ⃝ 2018 The Authors. Published by Elsevier B.V. r iew unde responsibility of the ECF22 organizers. Keywords: interfacial cracks; crack bridged zone; weak interface; boundary elements 1. Introduction Analysis of cracks growth in composite materials and in adhesive joints using models of a crack process zone (cohesive or bridged) includes the problem of displacements and stresses computation in crack process zones and in vicinity of the crack ti s. In this pap r th bridged crack approac will be considered a a cr ck process zone model. In this approach it is assumed that the stres intensity factors do not vanish at the crack tip. The problems of displacements and stresses analysis for bridged cracks have mainly considered for straight cracks in infinite homogeneous media. For bridged interfacial cracks between two semi-infinite homogeneous plates the problems were considered and solved firstly in (Goldstein and Perelmuter, 1999) by the singular integral-di ff erential equations method (planar problem). Similar problem (but without analysis of stresses at the bridged zone) was considered for anisotropic materials in (Ni and Nemat-Nasser, 2000). In the last two decades a number of papers were devoted to the application of the boundary integral equation (BIE) method to computation of the stress intensity factors for cracks on bi-material interfaces in finite size structures. In these papers interaction between crack surfaces was neither assumed nor considered, see review in (Hadjesfandiari and Dargush, 2011). Only few papers have been directed to analysis of straight bridged cracks in finite size structures. The extension of BIE approach for solving elasticity problems for curvilinear interfacial crack has been proposed and numerically implemented in (Perelmuter, 2013). © 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. ∗ Corresponding author. Tel.: + 7-495-433-6257; fax: + 7-499-739-9531. E-mail address: perelm@ipmnet.ru 2210-7843 c ⃝ 2018 The Authors. Published by Elsevier B.V. Peer-review under responsibility of the ECF22 organizers. ∗ Corresponding author. Tel.: + 7-495-433-6257; fax: + 7-499-739-9531. E-mail address: perelm ipmnet.ru 2210-7843 c ⃝ 2018 The Authors. Published by Elsevi r B.V. Peer-revi w under responsibility of the ECF22 orga izers. * 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. 10.1016/j.prostr.2018.12.153