PSI - Issue 13

ScienceDirect Available online at www.sciencedirect.com Available o line at ww.sciencedire t.com ScienceDirect Structural Integrity Procedia 00 (2016) 000 – 000 Procedia Structural Integrity 13 (2018) 15 2–15 7 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. © 2018 The Authors. Published by Elsevier B.V. Peer-review under responsibility of the ECF22 organizers. ECF22 - Loading and Environmental effects on Structural Integrity Application of the internal and external Williams functions for stress intensity factors assessment in plane stress problems Yarosl v Dubyk*, I or Orynyak, Elena Yakovleva G.S. Pysarenko Institute for Problem of Strength, National Academy of Sciences of Ukraine, 2 Tymiriazevska str, Kyiv, 01014, Ukraine Abstract Existing analytical methods for calculating stress intensity factors are the application of the complex variables functions or solutions based on the potential theory. Now days, computer programs, most based o the finite element method, are widely used, and allow one to obtain the stress intensity factors of any geometry with any combinations of boundary conditions with an accuracy sufficient for most engineering applications. Thus the further contribution in the analytical methods is questionable. It's preferable to use understandable and easy coding classical methods based on Williams functions, better known as Boundary Collocation Method. However, questions of the application of this method, its educational significance, determination of the real advantages and disadvantages of Williams' functions remain open. The main purpose of this paper is to investigate the possibility of applying internal and external Williams functions to find the stress intensity factors in plane problems. Also applying the global equilibrium which considerably improve accuracy and convergence of the analysis. © 2018 The Authors. Published by Elsevier B.V. Peer-review under responsibility of the ECF22 organizers. Keywords: Crack; stress intensit factor; inner and outer Williams function; convergence; Airy functions; static plane body 1. Introduction Williams and Pasadena (1957) function were first introduced to model stresses and displacements in the vicinity of crack tips in the 2D elastic formulation. Since then, these functions have been extensively used and presented in almost all handbooks on fracture mechanics (Fett, 2008). These functions essentially represent combinations of Eri function pairs given in polar coordinates in such a way that they result in zero stresses at crack edges. Williams functions have the following applications. ECF22 - Loading and Environmental effects on Structural Integrity Application of the internal and external Williams functions for stress intensity factors assessment in plane stress problems Yaroslav Dubyk*, Igor Orynyak, Elena Yakovleva G.S. Pysarenko Institute for Problem of Strength, National Academy of Sciences of Ukraine, 2 Tymiriazevska str, Kyiv, 01014, Ukraine Abstract Existing analytical methods for calculating stress intensity factors are the application of the complex variables functions or solutions based on the potential t eory. Nowad ys, computer programs, m st bas d on the fi ite el ment method, are widely used, and all w one to btain the stress intensity fa tors of any geome ry with any combinations of boundary c nditions with n accuracy sufficient for most engineering applications. Thus the further contribution in the analytical methods is questionable. It's preferable to use understandable and easy coding classical methods based on Williams functions, better known as Boundary Collocation Method. However, questions of the applic tion of this method, its educational significance, determination of the real advantages and disadvantages of Williams' functions remain open. The main purp se of this p per is to investigate the possibility of pplyi g internal and external Williams functions to find the stress inte sity factors in plane problems. Al o applying the global equilibrium which co siderably improve accuracy and convergence of the analysis. © 2018 The Aut ors. Published by Elsevier B.V. Peer-review under responsibility of the ECF22 organizers. Keywords: Crack; stre s intensity factor; inner and outer Williams function; convergenc ; Airy func ions; static plane body 1. Introduction Williams and Pasadena (1957) function were first introduced to model stresses and displacements in the vicinity of crack tips in the 2D elastic formulation. Since then, these functions have been extensively used and presented in almost all handbooks on fracture mechanics (Fett, 2008). These functions essentially represent combinations of Eri function pairs given in polar coordinates in such a way that they result in zero stresses at crack edges. Williams functions have the following applications. © 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.: +38-050-990-1227. E-mail address: dubykir@gmail.com * Corresponding author. Tel.: +38-050-990-1227. E-mail address: dubykir@gmail.com

* 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.2018.12.308