PSI - Issue 13

ScienceDirect Available online at www.sciencedirect.com Av ilable o line at www.sciencedire t.com ScienceDirect Structural Integrity Procedia 00 (2016) 000 – 000 Procedia Structural Integrity 13 (2018) 1514–152 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 Hydrogen Enhanced Fatigue Crack Growth Rates in a Ferritic Fe 3wt%Si Alloy Antonio Alvaro a , Di Wan b , Vigdis Olden a , Afrooz Barnoush b a SINTEF Industry, Dept. of Materials Integrity and Welding, 7456 Trondheim, Norway b Department of Mechanical and Industrial Engineering, Norwegian University of Science and Te hnology, 7491 Trondheim, Norway Abstract It is well known that the presence of hydrogen in ferrous materials promotes both static fracture and affect the material fatigue crack growth rates. The latter is often referred to as Hydrogen Enhanced Fatigue Crack Growth Rate (HE-FCGR) which defines the reduction of crack growth resistance of the material under cyclic stresses when hydrogen is present. When it comes to the determination of the life of components exposed to hydrogen it is therefore of paramount importance to establish such hydrogen induced variation in crack speed in the material in order to avoid unexpected catastrophic failures. In this study the fatigue crack growth rate was determined for a Fe-3wt%Si alloy. Compact tension specimens were used to determine the Paris regime of the fatigue crack growth rate curve of the material. Two environmental conditions were investigated: laboratory air and in-situ electrochemically charged hydrogen. Different mechanical conditions, in terms of load ratio (R=0.1 and R=0.5) and test frequency (f=0.1 Hz, 1 Hz and 10 Hz), were used under electrochemically charged hydrogen conditions. The results show that compared to the specimens tested in air, there is a clear detrimental effect of H for the specimens tested in hydrogen, in terms of accelerated crack growth. The strength of the impact of hydrogen in enhancing the fatigue crack growth rates of the Fe-3wt%Si alloy clearly depends on the test conditions. Fractographic investigations were also used to unveil the mechanisms involved in the process leading to accelerate crack growth in presence of hydrogen. © 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 he ECF22 organizers. ECF22 - Loading and Environmental effects on Structural Integrity Hydrogen Enhanced Fatigue Crack Growth Rates in a Ferritic Fe 3wt%Si Alloy Antonio Alvaro a , Di Wan b , Vigdis Olden a , Afrooz Barnoush b a SINTEF Industry, Dept. of Mat rials Integrity and Welding, 7456 Trondheim, Norway b Department of Mechanical and t ial Engineering, Norwegian University of Science and Technology, 7491 Trondheim, Norway Abstract It is well known that the presence of hydrogen in ferrous materials promotes both static fracture and affect the material fatigue crack growth rates. The latter is often referred to as Hydrogen Enh nced Fatigue Crack Growth R te (HE-FCGR) which defines the reduction of crack growth resistance of the material u der cyclic stresses when hydrogen is present. When it comes to t d termination of the life of compo ents exposed to hydrog n it is therefor of paramount importance to establish such hydrogen induced variati n in crack speed in the material in order to avoid un xpect d cat strophic failures. In this tudy the fatigue crack growth rate was determined for a Fe-3wt%Si alloy. Compact tension specimens were used to determine the Paris regime of the fatigue crack growth rate curve of the material. Tw environmental conditions w re investigated: laboratory air and in-situ electrochemically charged hydrogen. Different mechanical conditions, in terms of load ratio (R=0.1 and R=0.5) and test frequency (f=0.1 Hz, 1 Hz and 10 Hz), were used under electrochemically charged hydrogen c n itions. The results show th t compar d to the specimens tested in air, there is a cl ar detrimental eff ct of H for th specimens tested in hydrogen, in terms of a celerat crack growth. The trength of t impact of hydrogen in enhancing the fatigue crack growth rates of the Fe-3wt%Si alloy clearly depends on the test conditions. Fractographic investigations were also used to unveil the mechanisms involved in the process leading to accel rate crack gr wth in presence of hydrogen. © 2018 The Authors. Published by Elsevier B.V. Peer-review under responsibility of the ECF22 organizers. 1 Introduction It is well established that the presence of atomic H in ferrous materials under cyclic stresses affects the fatigue behavior of metallic materials and steels in particular. This is an important issue both for the new and long-standing applications in energy fields which operate in aggressive working environments, to avoid catastrophic consequences for environment, industrial economy and personnel health. Therefore the development of the knowledge of the © 2016 The Authors. Published by Elsevier B.V. Peer-review under responsibility of the Scientific Committee of PCF 2016. Keywords: Fatigue Crack Growth, Hydrgen Embrittlement, Steel Keywords: Fatigue Crack Growth, Hydrgen Embrittlement, Steel Keywords: High Pressure Turbine Blade; Creep; Finite Element Method; 3D Model; Simulation. 1 Introduction It is well established that the presence of atomic H in ferrous materials under cyclic stresses affects the fatigue behavior of metallic materials and steels in particular. This is an important issue both for the new and long-standing applications in energy fields which operate in aggressive working environments, to avoid catastrophic consequences for environment, industrial economy and personnel health. Therefore the development of the knowledge of the

* 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 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.2018.12.310