PSI - Issue 2_A

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 Struc ural Integrity 2 (2016) 1164–1172 Available online at www.sciencedirect.com ScienceDire t Structural Integrity Procedia 00 (2016) 000–000 Available online at www.sciencedirect.com ScienceDirect Structural Integrity Procedia 00 (2016) 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. 21st European Conference on Fracture, ECF21, 20-24 June 2016, Catania, Italy Comp tation of a d testing crack growth at 20 kHz lo d frequency Mohamed Sadek a, *, Jens Bergström a , Nils Hallbäck a , Christer Burman a a ) Karlstad University, Department of Engineering and Physics, SE-658 88 Karlstad Abstract Fatigue properties are evaluated in a large span of fatigue lives ranging from a few load cycles to more than 10 13 load cycles. If the interest is focused on fatigue lives above 10 7 load cycles, we speak of the very high cycle fatigue (VHCF) range. For evaluation of properties in the VHCF range one often needs to use higher load frequencies to be able to perform testing within a reasonable time. Therefore, the influence of load frequency on fatigue strength and fatigue crack growth is an important issue, both from testing and design perspectives. Within an EU-RFCS research project on the frequency influence on high strength steel fatigue properties the present study has been conducted on fatigue crack growth testing to determine threshold values and crack growth material parameters. The testing was analyzed by FE-computation to determine geometry factors for ΔK-determination. The testing was performed in a 20 kHz ultrasound resonance instrument. In such a system the whole load train needs to be designed to run at a resonance frequency of 20 kHz, and it implies that the specimen needs to be designed and computations performed by dynamic computational methods. As the crack grows the dynamic response of the specimen will change, and hence calculation to obtain the geometry factor is made with a progressing crack length. A uniaxial tensile load at 20 kHz frequency is applied to a single edged notched side-grooved flat specimen. The specimen dimensions are calculated in order to have a resonance frequency of 20 kHz, which is the frequency used for the experiments. Dynamic FEM computation, with a 3D-model and a quarter symmetry was used with one of the symmetry planes parallel to and in the crack growth line. To avoid crack surface interpenetration during the simulations a rigid thin sheet was introduced and used as a counter-face to the crack surface. The solution obtained was then combined with the breathing crack model proposed by Chati et. al. (1997) in order to solve for the irregularities observed when crack surface interpenetration occurs. Finally, the whole load train was considered. Thus, also the computed frequencies were very close to frequencies observed in experiments. The computation of stress intensities was made for varying crack lengths in a series of simulations. The geometry factor relation was determined and used in 20 kHz crack growth testing to control the actual stress intensity at the advancing crack tip. Comparison of computations and experimental results were made. © 2016 The Authors. Published by Elsevier B.V. Peer-review under responsibility of the Scientific Committee of ECF21. 21st European Conference on Fracture, ECF21, 20-24 June 2016, Catania, Italy Computation of and testing crack growth at 20 kHz load frequency Mohamed Sadek a, *, Jens Bergström a , Nils Hallbäck a , Christer Burman a a ) Karlstad University, Department of Engineering and Physics, SE-658 88 Karlstad Abstract Fatigue properties are evaluated in a large span of fatigue lives ranging from a few load cycles to more than 10 13 load cycles. If the int rest is focus d on f tigue lives above 10 7 load cycles, we speak of the very high cycle fatigue (VHCF) range. For evaluation of pr perties i the VHCF range one often needs to use high r load fr qu ncies to be able to perform testing within a re sonable time. Therefore, the influence of load frequ ncy n fatigue strength and fat gue crack growth is an important issue, both from testing and design p rspectives. Within an EU-RFCS research p oject on the frequency influence on high streng h te l fatigue properties the prese t study has been co ducted on fatigue crack grow h testing to d termine threshold values and crack growth material paramet rs. The testing was analyzed by FE-computation to de ermine e m ry factors for ΔK-determination. The esting w s performed in a 20 kHz ultrasound resonan e instrument. In such a system the whole load train needs to be designed to run at a resonance frequency of 20 kHz, and it implies that he spe imen ne ds o be designe and computations p rformed by dynamic c mputational meth ds. As the crack grows the dynamic r sponse of the specimen will change, and hence calculation to obtain the geome ry f ctor is made with a progressing crack length. A uniaxial t nsile load at 20 kHz frequency is applied to a single edged notched side-grooved flat specim n. The specimen dime sions are calculated in order to have a resonance frequency of 20 kHz, which is the frequency us d for the experiments. Dynamic FEM computation, with a 3D-model and a quarter symmetry was used with one of the symmetry planes parallel to and in the crack growth line. To avoid crack surface interpene ration during the simulations a rigid thin sheet was introduced and use as a counter-face to the crack surface. The solution obtained was then combined with the breathing crack model proposed by Ch ti et. al. (1997) in order to solve for the irregularities observed w rack surface interpenetrat on occurs. Finally, the whole load train was considere . Thu , also the computed frequencies were very close to frequencies observed in experiments. The comput tion of st ss intensities was made for varying crack l ngths in a series of simulations. The geometry factor relation was determined and used in 20 kHz crack growth testing to co trol the actual stress intensity at th advancing crack tip. Comparison of computations and experimental esults were made. © 2016 The Authors. Published by Elsevi r B.V. Peer-review under espons bility of the Scientific Committee of ECF21. Copyright © 2016 The Authors. Published by Elsevier B.V. This is an open access article under the CC BY-NC-ND license (http://cr ativecommon .org/licenses/by-nc-nd/4.0/). Peer-review under responsibility of the Scientific Committee of ECF21. © 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. Keywords: Crack growth; High frequency; Dynamic analysis; steel; threshold testing. Keywords: Crack growth; High frequency; Dynamic analysis; steel; threshold testing.

* Mohamed Sadek. Tel.: +4654-700-1944; fax: +46-54-700-1829. E-mail address: mohamed.sadek@kau.se * Mohamed Sadek. Tel.: +4654-700-1944; fax: +46-54-700-1829. E-mail a dress: mohamed.sadek@kau.se

* Corresponding author. Tel.: +351 218419991. E-mail address: amd@tecnico.ulisboa.pt 2452-3216 © 2016 The Authors. Published by Elsevier B.V. Peer-review und r responsibil ty of the Scientific Committee of ECF21. 2452-3216 © 2016 The Authors. Published by Elsevier B.V. Peer review under r sponsibility of the Scientific Committee of ECF21.

2452-3216 © 2016 The Authors. Published by Elsevier B.V. Peer-review under responsibility of the Scientific Committee of PCF 2016. Copyright © 2016 The Authors. Published by Elsevier B.V. This is an open access article under the CC BY-NC-ND license ( http://creativecommons.org/licenses/by-nc-nd/4.0/ ). Peer review under responsibility of the Scientific Committee of ECF21. 10.1016/j.prostr.2016.06.149