PSI - Issue 13

ScienceDirect Available online at www.sciencedirect.com Av ilable o line at ww.sciencedirect.com ienceDirect Structural Integrity Procedia 00 (2016) 000 – 000 Procedia Structural Integrity 13 (2018) 11 5–111 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 Prediction model for fatigue life and limit of steel based on small crack micromechanics Hiroaki Ito a* , Kazuki Shibanuma a ,Koya Ueda a , Masao Kinefuchi b , Katsuyuki Suzuki c , Manabu Enoki d a Department of Systems Innovation, the University of Tojyo, 7-3-1, Hongo, Bunkyo-ku, Tokyo, Japan, b KOBE STEEL, LTD, 1-5-5, Takatsukadai, Nishi-ku, Kobe, Hyogo, Japan, c Research into Artifacts, Center for Engineering, 5-1-5, Kashiwanoha, Kashiwa-shi, Chiba, Japan, d Department of Materials Engineering, the University of Tokyo, 7-3-1, Hongo, Bunkyo-ku, Tokyo, Japan Abstract It is very important to predict fatigue life and limit of steels for material design and they are affected by microstructures. Although a model for the prediction based on microstructural information was pr posed, uch model doesn’t con ider the other important factors, the stress distribution and the crack closure. This study employed the weight function in order to describe the effect of the stress distribution. For the crack closure, a crack closure equation for small fatigue cracks was employed. Also, tension/compression fatigue experiments using three different steels were carried out to validate this model. Predicted fatigue lives and limits showed good agreement with experimental results for all steels. These new extensions expanded the application of this model, e.g. bending conditions. © 2018 The Authors. Published by Elsevier B.V. Peer-revi w under responsibility of th ECF22 org niz rs. Keywords: Fatigu fracture; Prediction; Ferrite; Pearlite; Model; 1. Introduction Since fatigue fracture is one of the main causes for serious accidents of steel structures, fatigue properties of materials are very important for materials design and many researches have been done to explain it. Propagation of large cracks generally can be explained according to Paris equation. Fatigue properties of steels, such as fatigue life and fatigue limit, are said to be significantly affected by their micr structures. In other words, the size, orientation and spatial distribution of grains/phases dominate crack growth behavior. Tanaka et al. proposed a theory based on the interaction between a crack and grain boundaries to explain the microstructurally small crack behavior. (Tanaka et al., 1986) Although this is a simple one-dimensional model, complicated crack growth behaviour can be simulated with this. Shibanuma et al. developed a model predicting fatigue life and limit based on microstructural information of steels, which simplifies three dimensional fatigue fracture as a ECF22 - Loading and Environmental effects on Structural Integrity Prediction model for fatigue life and limit of steel based on small crack micromechanics Hiroaki Ito a* , Kazuki Shibanuma a ,Koya Ueda a , Masao Kinefuchi b , Katsuyuki Suzuki c , Manabu Enoki d a Department of Systems Innovation, the University of Tojyo, 7-3-1, Hongo, Bunkyo-ku, Tokyo, Japan, b KOBE STEEL, LTD, 1-5-5, Taka sukadai, Nishi-ku, Kobe, Hyogo, Japan, c Research into Artifacts, Center for Engineering, 5-1-5, Kashiwanoha, Kashiwa-shi, Chiba, Jap n, d Dep rtment of Materials En ineering th Universi y of Tokyo, 7-3-1, H ngo, Bunkyo-ku, Tokyo, Japan Abstract It is very important to predict fatigue life and limit of steels for material design and they are affected by microstructures. Although a model for the prediction based on microstructural information was proposed, such model doesn’t consider the other important factors, the stress distribution and the crack closure. This study employed the weight function in order to describe the effect of the stress distribution. For the crack closure, a crack closure equation for small fatigue cracks was employed. Also, tension/compression fatigue experiments using three different steels were carried out to validate this model. Predicted fatigue lives and limits showed good agreement with experimental results for all steels. These new extensions expanded the application of this model, e.g. bending conditions. © 2018 The Aut ors. Published by Elsevier B.V. Peer-review under responsibility of the ECF22 organizers. Keywords: Fatigue fracture; Prediction; Ferrite; Pearlite; Model; 1. Introduction Since fatigue fracture is one of the main causes for serious accidents of steel structures, fatigue properties of materials are very important for materials design and many researches have been done to explain it. Propagation f large c acks generally can be explained according to Paris equation. Fatigue properties of steels, such as f tigue life and fatigue limit, are said to be significantly affected by their micr structures. In other words, the size, orientation and spatial di tribution of grains/ph s s dominate crack growth behavior. Tanaka et al. pr posed a t eory based on the interaction between a crack and grain boundaries to explain the microstructurally small crack behavior. (Tanaka et al., 1986) Although this is a simple one-dimensional model, complicated crack growth behaviour can be simulat d with this. Shiban ma et al. developed a model predicting fatigue life and limit based on microstructural information of steels, which simplifies three dimensional fatigue fracture as a © 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 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.2018.12.232