PSI - Issue 6

ScienceDirect Available online at www.sciencedirect.com Av ilable o line at www.sciencedire t.com cienceDirect Structural Integrity Procedia 00 (2016) 000 – 000 Procedia Structu al Integrity 6 (2017) 269–275 Available online at www.sciencedirect.com ScienceDirect Structural Integrity Procedia 00 (2017) 000 – 000 Available online at www.sciencedirect.com ScienceDirect Structural Integrity Procedia 00 (2017) 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. Copyright © 2017 The Authors. Published by Elsevier B.V. Peer-review u der responsibility of the MCM 2017 orga izers. XXVII International Conference “Mathematical and Computer Simulations in Mechanics of Solids and Structures”. Fundamentals of Static and Dynamic Fracture (MCM 2017) Study on Crack Branching Condition for Brittle Crack Propagation in Steels Tonsho Fumiaki a , Kawabata Tomoya a , Aihara Shuji a a The University of Tokyo,7-3-1,Hongo, Bunkyo-ku, Tokyo, 113-8654, Japan Abstract In brittle material like glass, it is observed that crack branches when the crack speed gets more than the material critical velocity. When the crack branches, the driving force at running crack tip gets lower, so it is possible to prevent the structure from serious failur . In this paper, using the devised und r-matched welded joint to mplement the higher cr ck vel city, the mechanism of crack branching and surface roughening is investigated by experiments and the dynamic Finite Element Method (FEM) analysis.In the result, crack surface roughening happens when the crack velocity is around 800m/s, contrary to the findings of the elastic dynamic fracture mechanics. FEM analysis was conducted to explain the phenomenon and it is possible that the high stress triaxiality can be the critical condition for crack branching. © 2017 The Authors. Published by Elsevier B.V. Peer-review under responsibility of the MCM 2017 organizers. Keywords: Brittle crack propagation; Steel; Dynamic fracture; Finite Element Method analysis 1. Introduction Large struct re ca collapse by brittle fractur , so technology is required for rresting brittle crack propagation[1]. In brittle material like glass or PMMA, it is observed that crack branching occurs when the crack speed gets more than the material critical velocity[2]. However, the amount of study is small which focuses on the crack branching behavior in steels. When the crack branches, the driving force near the crack tip gets lower, so the material gets less likely to collapse. In this study, for investigating the possibility of utilizing the crack branching for arresting the crack propagation, critical condition for crack branching is examined with the brittle crack propagation test and FEM analysis. XXVII International Conference “Mathematical and Computer Simulations in echanics of Solids and Structures”. Fundamentals of Static and Dynamic Fracture (MCM 2017) Study on Crack Branching Condition for Brittle Crack Propagati n in Steels Tonsho Fu iaki a , Kawabata Tomoya a , Aihara Shuji a a The University of Tokyo,7-3-1,Hongo, Bunkyo-ku, Tokyo, 113-8654, Japan Abstract In brittle material like glass, it is observed that crack bran hes when the crack speed gets more than the material critical velocity. When the crack branches, the driving force at running crack tip gets l wer, so it is possible to prevent the structure from serious failure. In this paper, using the devised under-matched welded join to implement the higher crack velocity, the mechanism of crack bra ching and surface roughenin is investigat d by experiments and the dyn mic Finite Eleme t Method (FEM) analysis.I the result, crack surface roughening happens when the crack velocity is ar und 800m/s, contrary to the findings of the elastic dynamic fracture mechanics. FEM a alysis was co ducted to explain the phenomenon and it is possible that the high stress triaxiality can be the critical condition for crack branching. © 2017 The Authors. Published by Elsevier B.V. Peer-review under responsibility of the MCM 2017 organizers. Keywords: Brittle crack propagation; Steel; Dynamic fracture; Finite Element Method analysis 1. Introduction Large structure can collapse by brittle fracture, so technology is required for arresti g brittle crack propagation[1]. In brittle material like glas r PMMA, it is observed that crack branching occurs when the crack speed gets more than the material critical velocity[2]. However, the amount of study is small which focus s on t e crack branching behavior in steels. When the crack branches, the driving force near the crack tip gets lower, so the material gets less likely to collapse. In this study, f r investigating the possibility of utilizing the crack branching for arresting the crack propagation, critical condition for crack branching is examined with the brittle crack propagation test and FEM analysis. © 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 © 2017 The Authors. Published by Elsevier B.V. Peer-review under responsibility of the MCM 2017 organizers. 2452-3216 © 2017 The Authors. Published by Elsevier B.V. Peer-review under responsibility of the MCM 2017 organizers.

2452-3216 © 2016 The Authors. Published by Elsevier B.V. Peer-review under responsibility of the Scientific Committee of PCF 2016.

2452-3216 Copyright  2017 The Authors. Published by Elsevier B.V. Peer-review under responsibility of the MCM 2017 organizers. 10.1016/j.prostr.2017.11.041

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