PSI - Issue 2_B

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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 Variation of transitional functions in multiscale fatigue crack growth of superalloys K. K. Tang a, * , F. Berto b,c , H. Wu a a School of Aerospace Engineering and Applied Mechanics, Tongji University, Shanghai 200092, China b Department of Management and Engineering, University of Padua, Stradella San Nicola, 36100 Vicenza, Italy c Department of Engineering Design and Materials, Richard Birkelands vei 2b, 7491 Trondheim, Norway Abstract Multiscale fatigue crack growth model (MFCGM) can provide better explanation for the multiscale effects on the process of superalloy fatigue. Transitional functions that account for material, loading and geometry effects are incorporated in the MFCGM and play vi al role in the proposed model. They are the reflection of the combined microscopic and macroscopic effects. Though validity of transitional functions has been proved in former research, there are still a few critical issues to be clarified. The biggest concern is the assumption of in easing or decreasing trend of transitional curves. It is un ni ble that the ge eral trends of these curves agree with the physical phenomena of material degrada ion, loading restriction and size ffec s. However, coefficients i transitional functions remain to be specified. Und r current circumstance, it is almost impossible to identify these scale parameters. Nevertheless, it is still feasible to mploy appropriate coefficients and vary each of the three transitional functions. Variation of transitional functions correspondingly leads to the change of fatigue life of superalloys. Experimental fatigue data of 2024-T3 Al sheets is adopted to modify transitional functions related to material, loading and geometry. Thus the most reasonable and appropriate set of transitional functions are determined. It is found that transitional coefficients ζ η and λ play different role in fatigue crack growth behaviors. Particularly emphasized is the geometric coefficient λ . A set of transitional coefficients are determined such that fatigue crack growth of 2024-T3 Al sheets can be best described and explained. The proposed approach potentially offers the possible reference for engineering safety designs. © 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 Variation of transitional functions in multiscale fatigue crack growth of superalloys K. K. Tang a, * , F. Berto b,c , H. Wu a a School of Aerospace Engineering and Applied Mechanics, Tongji University, Shanghai 200092, China b Department of Management and Engineering, University of Padua, Stradella San Nicola, 36100 Vicenza, Italy c Department of En ineering Desi n and Materials, Richard Birkelands vei 2b, 7491 Trondheim, Norway Abstract Multiscale fatigue crack growth model (MFCGM) can provide better explanation for the multiscale effects on the process of superalloy f ti . T nsitional functions that account for material, loading and geomet y effects are incorporated in the MFCGM and play vit l rol in the pr posed m del. They are the reflection of the combined ic oscopic and macroscopic effects. Though validity of transitio al functi ns has b en proved in form r researc , there ar still a few ritical issues to b clarified. The biggest c ncer s the assumption of increasing or decreasing tr nd of transitional curves. It is undeniable that th general trends of these curves agree with the physical ph nom na of material degr dation, ading restriction and size effects. However, co ffici nts in transitional functions remain to be specified. Under current c rcumst nce, it is almost impossibl t identify these scal p r meters. Neverthele s, it is still feasible to employ approp iate coefficie ts and vary each of th hre transitional functions. Variation of transitional functions correspondingl leads to the change of f tigue life of super lloys. Experiment atigue data of 2024-T3 Al sheets is adopted to odify tr nsition l functions r lat d to material, loading and geom try. Thus the most reasonable and appropriat et of transitional functions are determined. It is found that t ansitional coeffici nts ζ η and λ play different role in fatigue crack growth behaviors. Particularly mphasized is the geome ric coefficient λ . A se of transitional coefficients are determ ned such that fatigue crack growth of 2024-T3 Al he ts can be best described and explained. The proposed approach potentially offers the possible reference for engineering safety designs. © 2016 The Authors. Published by Els vier B.V. Peer-review under espons bility of the Scientific Committee of ECF21. Keywords: MFCGM; transitional functions; variation; fatigue; transitional coefficient; 2024-T3 Al sheets Copyright © 2016 The Authors. Published by Elsevier B.V. This is an open access article under the CC BY-NC-ND license (http://creativ commons.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: MFCGM; transitional functions; variation; fatigue; transitional coefficient; 2024-T3 Al sheets

* Corresponding author. Tel.: +351 218419991. E-mail address: amd@tecnico.ulisboa.pt 2452-3216 © 2016 The Authors. Published by Elsevier B.V. Peer-review under responsibility 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. * Corresponding author. Tel.: +86-21-65982267; fax: +86-21-65982267. E-mail address: kktang@tongji.edu.cn * Corresponding author. Tel.: +86-21-65982267; fax: +86-21-65982267. E-mail address: kktang@tongji.edu.cn

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.2016.06.236