PSI - Issue 13

ScienceDirect Available online at www.sciencedirect.com Av ilable o line at ww.sciencedire t.com ienceDirect Structural Integrity Procedia 00 (2016) 000 – 000 Procedia Structural Integrity 13 (2018) 1221–1225 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 The influence of grain size on cleavage crack propagation resistance in ferritic steels Yuta Suzuki a* , Takuhiro Hemmi a , Fuminori Yanagimoto a , Kazuki Shibanuma a a Department of Systems Innovation, the University of Tojyo, 7-3-1, Hongo, Bunkyo-ku, Tokyo, Japan Abstract Cleavage crack propagation in steels occurs suddenly and at high speed, and h s a risk of giving structures crucial damage. Thus, it is a phenomenon to be prevented absolutely. It is well known that microstructures, for example grain size or orientation, make a substantial contribution to material resistance to cleavage fracture, but the effect of microstructures on mechanism of fracture is practically hardly elucidated at the present moment. This study firstly carried out arrest tests to evaluate the relation between cleavage crack propagation and grain size that was the most basic characteristic of microstructures, and experimented to describe the elementary process on the microscopic mechanism. The numerical analysis model was developed to express the results of these experiments, and showed that the larger grain size was, the larger cleavage crack propagation resistance was. © 2018 The Authors. Published by Elsevier B.V. Peer-review under responsibility of the ECF22 organizers. Keywords: Cleavage; Crack propagation; Arrest toughness; Microstructure; XFEM; 1. Introduction It can be easily inferred that microstructures, like grain size, grain orientation, have a strong effect on cleavage fracture. Grain size is the most basic characteristic to describe microstructures, and it is empirically known that the smaller it is, the more easily crack arrests. However, no attempt has been made to elucidate the relation between grain size and arrest toughness directly by measuring each arrest toughness for steels which have the same chemical composition and the diff rent grain size because producing such steels requir s advanced technology. Therefore, there is no firm evidence that empirical knowledge is correct, and it is necessary to perform cleavage crack arrest toughness tests to ascertain it. The absorbed energy in cleav ge crack propagatio is composed of the energy of forming cleavage plane at the (100) plane in grains and tear-ridge by breaking unbroken portion of the grain boundary. The former energy is negligibly small compared to the latter energy, so it can be calculated by considering the formation energy of tear-ridge between grains as the energy absorption amount. However, this derivation is a formula estimated by observing a part of fracture surface and contains many uncertain terms. In other words, it cannot be said that there is an experimental fact to prove it. ECF22 - Loading and Environmental effects on Structural Integrity The influence of grain size on cleavage crack propagation resistance in ferritic steels Yuta Suzuki a* , Takuhiro Hemmi a , Fuminori Yanagimoto a , Kazuki Shibanuma a a Department of Systems Innovation, the University of Tojyo, 7-3-1, Hongo, Bunkyo-ku, Tokyo, Japan Abstract Cleavage crack propagation in steels occurs suddenly and at high speed, and has a risk of giving structures crucial damage. Thus, it is a ph nomenon to be prevented absol tely. It is well known t at microstructures, for example g ain size o orient tion, make a substantial contribu ion to material re istance to cleavage fracture, but the effect of microstructures on m chanism of fracture is prac ically hardly elucidated at the pre e t moment. This study firstly carried out arrest tests to evaluate the relation between cleavage crack propagation and grain siz that was the most basic characte istic f mic o truc ures, and experimented to d scribe the elementary process on the mic oscopic mechanism. The numerical analysis model was developed to expr ss the r sults of thes exp ri ts, and showed t at the larger grain size was, t larger cleavage crack propagation resistance was. © 2018 The Authors. Published by Elsevier B.V. Peer-review under responsibility of the ECF22 organizers. Keywords: Cleavage; Crack propagation; Arrest toughness; Microstructure; XFEM; 1. Introduction It can be easily inferred that microstructures, like grain size, grain orientation, have a strong effect on cleavage fracture. Grain size is the most basic characteristic to describe microstructures, and it is empirically known that the smaller it is, the more easily crack arrests. However, no attempt has been made to elucidate the relation between grain size and arrest toughness directly by measuring each arrest toughness for steels which have the same chemical composition and the different grain size because producing such steels requires advanced technology. Therefore, there is no firm evidence that mpirical knowl dge is correct, and it is necessary to perform cleavage crack arrest toughness tests to ascertain it. The absorbed energy in cleavage crack propagation is composed of the energy of forming cleavage plane at the (100) plane in grains and tear-ridge by breaking unbroken portion of the grain boundary. The former energy is negligibly small compared to the latter energy, so it can be calculated by considering the formation energy of tear-ridge between grains as the energy absorption amount. However, this derivation is a formula estimated by observing a part of fracture surface and contains many uncertain terms. In other words, it cannot be said that there is an experimental fact to prove it. © 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.: +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.2018.12.251