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 Structu al Integrity 13 (2018) 694–699 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. microstructurally fatigue small crack in a laminated Ti – 6Al – 4V alloy Akira Maenosono a *, Motomichi Koyama a , Yoshihisa Tanaka b , Shien Ri c , Qinghu Wang c , and Hiroshi Noguchi a a Graduate School of Engineering, Kyushu University, 744 Motooka Nishi-ku Fukuoka 819-0395, Japan b National Institute for Materials Science, 1-2-1 Sengen, Tsukuba, Ibaraki 305-0047, Japan c National Institute of Advanced Industrial Science and Technology, 1-1-1 Umezono, Tsukuba, Ibaraki 305-8560, Japan Abstract The fatigue life of Ti – 6Al – 4V alloy exhibits significant scatter, which is derived from the statistical scatter of uncontrollable material factors. In particular, crack propagation behaviors in microstructurally small cracks strongly depend on material factors. It is necessary to understand the mechanisms underlying the scatter of fatigue properties. In this study, the dominant material/mechanical factors of microstructurally small fatigue crack growth behaviors are extracted, and the mechanisms of fatigue crack propagation life scatter derived from them are clarified. A Ti – 6Al – 4V billet was studied in which the microstructure wa s fully laminated with α and β phases. The major constituent phase was α. Microstructurally small artificial defects were introduced at a center of prior β grains by a focused ion beam (FIB). A fatigue test was carried out at a stress ratio R = 0, stress amplitude σ a = 400 MPa, and frequency 1.3 × 10 -2 Hz in a vacuum using scanning electron microscopy (SEM). In situ SEM observation was carried out around each FIB notch. After the fatigue test, the dependence of the crack growth path on crystallographic orientation was investigated by using electron backscattered diffraction. It was found that microstructurally small crack growth behaviors depended on crystallographic orientation. The dominant crack growth mechanism was the mode II crack growth mechanism by shear stress along the basal plane as a driving force. The dominant factor that causes large scatter of fatigue lif in a α - Ti – 6Al – 4V alloy is the differ nc in re olved shear stress along the basal plane. Specifically, the difference in the angle betw en the basal plane and loading direction, the low reproducibility of the mode II crack growth mechanism, and the random position of pre-existing damage cause the scatter of fatigue crack growth rate. ECF22 - Loading and Environmental effects on Structural Integrity Crystallographic orientation-dependent growth mode of microstructurally fatigue small crack in a laminated Ti – 6Al – 4V alloy Akira Maenosono a *, Motomichi Koyama a , Yoshihisa Tanaka b , Shien Ri c , Qinghu Wang c , and Hiro hi Noguchi a a Graduate School of Engineering, Kyushu University, 744 Motooka Nishi-ku Fukuoka 819-0395, Japan b Nati nal Institute for Materials Science, 1-2-1 Sengen, Tsukuba, Ibaraki 305-0047, Japan c National Institute of Advanced Industrial Science and Technology, 1-1-1 Umezono, Tsukuba, Ibaraki 305-8560, Japan Abstract Th fatigue life of Ti – 6Al – 4V alloy exhibits significant scatter, which is derived from the statistical scatter of uncontrollable material factors. In particular, crack propagation behaviors in microstructurally small cracks strongly depend on material factors. It is necessary to understand the mechanisms underlyin the scatter of fatigue prop rties. In this study, the do inant material/mechanical f ct rs of mi rostructurally small fatigue cra k growth behaviors are extracted, and th mechanisms of fatigue crack propagation life scatter derived from them are clarified. A Ti – 6Al – 4V billet was st died in which the micro tructure wa s fully laminat d with α and β phases. The major constituent phase was α. Microstructurally small artificial defects were introduced at a center of prior β grains by a focused ion beam (FIB). A fatigue test was carried out at a stress ratio R = 0, stress amplitude σ a = 400 MPa, and frequency 1.3 × 10 -2 Hz in a vacuum using scanning ele tron microscopy (SEM). In situ SEM observation was carried out around ach FIB otch. After the fatigue test, the dependence of the cr ck growth path on crystallographic orientation was i vestigated by using elect on backscatt red diffraction. It was found that microstructurally small crack growt behaviors d pend d on crystallogr phic orientation. The dominant crack growth mechanism was the mode II crack growth mechanism by shear stress along the basal plane as a driving force. The dominant factor that causes large scatter of fatigue life in a α - Ti – 6Al – 4V alloy is the differen e i resolved shear stress along t basal plane. Specifically, t e differe ce in the angle between the basal plane and loading direction, the low r producibility of the mode II crack growth mechanism, and the random position of pre-existing damage cause the scatter of fatigue crack growth rate. ECF22 - Loading and Environmental effects on Structural Integrity Crystallographic orientation-dependent growth mode of © 2016 The Authors. Published by Elsevier B.V. Peer-review under responsibility of the Scientific Committee of PCF 2016. © 2018 The Authors. Published by Elsevier B.V. Peer-review under responsibility of the ECF22 organizers. © 2018 Th A thors. Published b Elsevier B.V. Peer-review under responsibility of the ECF22 organizers. © 2018 The Autho s. Published by Elsevier B.V. Peer-review under responsibil ty of the ECF22 organizers. Keywords: High Pressure Turbine Blade; Creep; Finite Element Method; 3D Model; Simulation. Keywords: fatigue crack growth, microstructurally-small crack, in situ microscopic observation, Ti – 6Al – 4V alloy, fully laminated microstructure Keywords: fatigue crack growth, microstructurally-small crack, in situ microscopic observation, Ti – 6Al – 4V alloy, fully laminated microstructure

* 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. * Correspon ing au hor. Tel.: +81-92-802-7677; fax: +81-92-802-0001. E-mail address: 2te17692t@s.kuyshu-u.ac.jp * Corresponding author. Tel.: +81-92-802-7677; fax: +81-92-802-0001. E-mail address: 2te17692t@s.kuyshu-u.ac.jp

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.2018.12.115