PSI - Issue 13

ScienceDirect Available online at www.sciencedirect.com Av ilable o line at ww.sciencedire t.com Sci ceDirect Structural Integrity Procedia 00 (2016) 000 – 000 Procedia Structural Integrity 13 (2018) 162 –1625 Available online at www.sciencedirect.com ScienceDirect Structural Integrity Procedia 00 (2018) 000–000 Available online at www.sciencedirect.com ScienceDirect Structural Integrity 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 Structural-time nature of the dynamic instability of the fracture process Yuri Petrov a,b,c , Nikita Kazarinov a,b * a Saint Petersburg State University, Saint Petersburg 199034, Russia b Institute of problems of mechanical engineering, Saint Petersburg 199178, Russia c Research Institute for Mechanics, National Research Lobachevsky State University of Nizhni Novgorod, 603600, Nijnii Novgorod, Russia Abstract Principal effects of dynamic instability of the fracture process are investigated. Particularly an issue of a dependence of stress intensity factor ( ) on crack velocity ( ) is discussed. Uniqueness, related to the given material, and even existence of this dependence has been a matter of discussion among researchers, since contradicting experimental results have been reported in the literature over last decades. In this paper results of numerical simulations of the crack propagation process are presented. A numerical scheme based on finite element method and incubation time fracture criterion was developed. Scattering of the values during the propagation process is considered to be a feature principally related to a spatial-temporal nature of the fracture process. It is found that quasistatic loading is characterized by a small scatter of the values and fitting of the data can be performed in order to obtain s me well-kn wn − curve. I the case of a pulse loading the scatter i much higher and it can be concluded that a wide range of val es correspond to a particular crack velocity and no unique continuous − curve can be associated with the process. These results are supported by well-known experimental observations. Thus, it is proved that the incubation time fracture criterion makes it possible to investigate dynamic crack propagation for a wide variety of loading conditions (quasistatic, high rate and short pulse loading) and only one extra material parameter – the incubation time is needed to predict a big variety of effects of the dynamic instability of the fracture process. This is a huge advantage comparing to a widespread approach, which involves complicated experimental determination of material strain rate dependencies and an a priori given − relationship. © 2018 The Authors. Published by Elsevier B.V. Peer-review under responsibility of the ECF22 organizers. ECF22 - Loading and Environmental effects on Structural Integrity Structural-time nature of the dynamic instability of the fracture process Yuri Petrov a,b,c , Nikita Kazarinov a,b * a Saint Pet rsburg State University, Sa t Petersburg 199034, Russia b I stitute of problems of mech nical engineering, Sain Petersburg 199178, Russia c Research Institute for Mechanics, National Research Lobachevsky State University of Nizhni Novgorod, 603600, Nijnii Novgorod, Russia Abstract Principal effects of dynami instability of the fractur process ar inv stigated. Particularly an issue of a d pendence of stres intensity factor ( ) on crack velocity ( ) is discuss d. Uniqueness, related o th given m te ial, and even existenc of this dependence has been a matter of d cussion among researchers, since contradicting experimental results have been re ort d in the literature over last decades. In this paper r sults of numerical s ulations of the crack propagation proc ss are pr sented. A n meric l scheme based on finite element me hod nd incubation time f acture criterion was developed. Scattering of he values during the propagation process s conside ed to b a feature prin ipally related to a spatial-temporal nature of the fractu e process. It is found that quasis atic loadi g is charact rized by a mall scatt r of the values and f tting of t ta can be p rf rme i order to obtai some w ll-known − curve. In the case f a pulse lo ding the scatter is m ch h gher and it b conclud that a wide range of val es corr spond to a particular crack v locity nd no unique continuous − curve can be ssociat with th process. Thes result are supported by well-known experiment l bserv tions. Thus, it is proved that the i cubation time fracture criterion makes it possible to investigat dynamic crack propagation for a wide variety of loading con tions (qu sistatic, high rate and short pulse load ng) and only one xt a material parameter – the i cubati n ti e is needed to r dict a big variety of effects of the dynamic instability of the fracture process. This is a huge advantage comparing to a widespread approach, which involves complicated experimental determination of material strain rate dependencies and an a priori given − relationship. © 2018 The Authors. Publ shed by Elsevier B.V. Peer-review under responsibility of the ECF22 organizers. © 2018 The Author . Published by Elsevier B.V. Peer-review under responsibility of the ECF22 organizers.

© 2016 The Authors. Published by Elsevier B.V. Peer-review under responsibility of the Scientific Committee of PCF 2016. Keywords: Dynamic fracture, crack propagation, K-v dependence, incubation time, FEM Keywords: Dynamic fracture, crack propagation, K-v dependence, incubation time, FEM Keywords: High Pressure Turbine Blade; Creep; Finite Element Method; 3D Model; Simulation.

* Corresponding author. Tel.: +7-964-366-64-64. E-mail address: n.kazarinov@spbu.ru * Correspon ing author. Tel.: +7-964-366-64-64. E-mail address: n.kazarinov@spbu.ru

* Corresponding author. Tel.: +351 218419991. E-mail address: amd@tecnico.ulisboa.pt 2452 3216 © 2018 Th Authors. Published by Elsevie B.V. Peer-review under responsibility of the ECF22 organizers. 2452-3216 © 2018 The Authors. Published by Elsevier B.V. Peer-review under responsibility of the ECF22 organizers.

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.2018.12.341