PSI - Issue 13

ScienceDirect Available online at www.sciencedirect.com Av ilable o line at ww.sciencedire t.com ienceDirect Structural Integrity Procedia 00 (2016) 000 – 000 Procedia Structu al Integrity 13 (2018) 535–541 Available online at www.sciencedirect.com ScienceDirect Structural Integrity Procedia 00 (2018) 000 – 000 Available online at www.sciencedirect.com ScienceDirect Structural Int 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 Experimental and numerical investigation of stress concentration and strength prediction of carbon/epoxy composites Emre Özaslan a,b , Bülent Ac r b , Mehmet A. Güler a, *, a TOBB Economy and Technology University, Söğütözü, Ankara 06560, Turkey b Roketsan Inc. Elmadağ, Ankara 06780, Turkey Abstract Unidirectional composites are very popular structural materials used in aerospace, marine, energy and automotive industries, thanks to their superior m terial properties. However, the mechanical behavior of compo ite mater als is more complicated than isotropic materials because of their anisotropic nature. Also, stress concentration presence on the structure, like a hole, makes the problem further complicated. Therefore, enormous numbers of tests are required in understanding the mechanical behavior and strength of composites which contain stress concentration. Accurate finite element analysis and analytical models enable us to understand mechanical behavior and predict the strength of composites without enormous number of tests which cost serious time and money. In this study, unidirectional Carbon/Epoxy composite specimens with central circular holes were investigated in terms of stress concentration factor and strength prediction. The composite specimens which had different specimen width (W) to hole diameter (D) ratio were tested to investigate the effect of hole size on the stress concentration and strength. Also, specimens which had same specimen width to hole diameter ratio, but different sizes were tested to investigate the size effect. Finite element analysis were performed to determine th stress concentration factor for all s ecimen configurations. Also, Point stress criteria (PSC) was used to pr dict strength of the specimens. For quasi-isotropic laminat , it was found that the tress concentration factor at the hole tip increases approximately %15 as W/D ratio dec ased fr m 6 o 3. Also, it is observed that as W/D ratio quadrupled with constant pecimen width the failure strength incr ases by %62.4. For the specimens which had s me width to hole diameter ratio but different (sc led) dimensions, the stress concentration factor t t e hole tip was seen to b identical as expecte . For these sp cimens, s W/D ratio doubled the specimen fa lure strength reduces by %13.2 because of the size ffect. For all type of specime s, the PSC method could predict the strength of specimens with maximum %8 error. ECF22 - Loading and Environmental effects on Structural Integrity Experimental and numerical investigation of stress concentration and strength prediction of carbon/epoxy composites Emre Özaslan a,b , Bülent Acar b , Mehmet A. Güler a, *, a TOBB Economy and Technology University, Söğütözü, Ankara 06560, Turkey b Roketsan I c. Elmadağ, Ankara 06780 Turkey Abstract Unidirectional composites are very popular structural materials used in aerospace, marine, energy and automotive industries, thanks to their superior material prop rti s. However, the mech nic l behavior of composite materials is more complicated than isotropic materials because of their anisotropic nature. Also, stress c ncentration presence on th structure, like a hole, makes th problem further complicated. Th refore, enormous numbers of test are requir d in understa ding the mechanical b havior and strength f co posit s which contain stress concentration. Accurate finite element analysis and analytical models enable us to understand mechanical behavior and predict the strength of composites without normous number of tests which cost serio time and money. In this study, u idirectional Carbo /Epoxy site specimens with central circular holes were investigated in ter s of stress concentration factor a d strength prediction. The co posite speci e s hich had different specimen width (W) to hole diameter (D) ratio were tested to i ve tigate the ffect of hole size on the stress concentration and strength. Also, specimens which had same specimen idth to hole diameter ratio, but different sizes were tested to i v stigate th size effect. Finite element analysis were performed to determine th str s concentration factor for all sp cimen c nfigurations. Al o, Point tress crit ria (PSC) was us d to predict str ngth of t pecimens. Fo quasi-isotropic l minate, it was found that the str ss co cent ation factor at the hole tip increases approximately %15 as W/D atio d cre sed fr m 6 to 3. Also, it is observed that as W/D ratio quadru l d with constant specimen width the failure streng h increases by %62.4. For the specimens which had same wi th to hole di met r ratio but different (scaled) imensions, the stress co c ntration factor at the ole tip was seen to be identical as expected. For these specimens, as W/D ratio doubled the pecim n failure strength reduces by %13.2 because of th size effect. For all type of specimens, the PSC method could predict th strength of specimens with maximum %8 error.

© 2016 The Authors. Published by Elsevier B.V. Peer-review under responsibility of the Scientific Committee of PCF 2016. © 2018 The Authors. Published by Elsevier B.V. Peer-review under responsibility of the ECF22 organizers. © 2018 The Authors. Published by Elsevier B.V. Peer-review under responsibility of the ECF22 organizers. © 2018 The Authors. Published by Elsevier B.V. Peer-review under responsibility of the ECF22 organizers. Keywords: Stress concentraiton; Composite materials; PSC

Keywords: Stress concentraiton; Composite materials; PSC

Keywords: High Pressure Turbine Blade; Creep; Finite Element Method; 3D Model; Simulation.

* Corresponding author. Tel.: +90-312-292-4088 ; fax: +90-312-292-4091 . E-mail address: mguler@etu.edu.tr * Corresponding author. Tel.: +90-312-292-4088 ; fax: +90-312-292-4091 . E-mail ad ress: mguler@etu.edu.tr

* 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.2018.12.088