PSI - Issue 13

ScienceDirect Available online at www.sciencedirect.com Av ilable o line at www.sciencedire t.com cienceDirect Structural Integrity Procedia 00 (2016) 000 – 000 Procedia Structural Integrity 13 8 51–56 Available online at www.sciencedirect.com ScienceDirect Structural Integrity Procedia 00 (2018) 000 – 000 Available online at www.sciencedirect.com ScienceDirect Structural I tegrity 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 Fracture behavior of rock plate under static and dynamic combined loads Guiyun Gao* Institute of Crustal Dynamics, China Earthquake Administration, Beijing 100085, China It is critical to understand the dynamic fracture and crack propagation of confined rocks in geophysics and geoengineering application, such as earthquake fault rupture and in-situ stress measurement. The objective of this paper is to characterize the dynamic fracture behavior of rock plate especially under uniaxial compression using the DIC method combined with ultra-high speed photography. Using a modified hydraulic pump, the uniaxial compression was exerted at the top and bottom ends of the rock plate. Dynamic crack pr pagatio tests of plate specimen w re condu ted using split Hopkinson pressure bar (SHPB) and the fracture processes were captured by an ultra-high speed photography. The displacement and strain fields of the dynamic fracture process were calculated using DIC. By setting the virtual digital extensometer, the crack-tip position, crack propagation velocity and the dynamic fracture toughness were obtained. Results show that the fr acture toughness increases from 1.39 MPa∙m 1/2 to 2.25 MPa∙m 1/2 , and the crack propagation velocity increases from 843.6 m/s to 1148.3 m/s when the incident velocity increases from 8.95m/s to 19.3m/s. The crack propagation velocity is higher than that obtained from small specimen such as NSCB specimen (Gao et al., 2015). Crack propagation velocity in rock plate is higher than that in small specimen such as notched semi-circular bending (NSCB) specimen of rock. There is one main crack path under lower gas pressure, while crack bifurcation occurs under high loading pressure. Crack propagation velocity and crack arrest length decrease with the increase of the hydraulic compressive pressure. If the plate is free of confining stress before dynamic loading, the crack propagation velocity is about 965.0 m/s. The crack propagation velocity decreases with the increase of hydraulic confining stress, and it reduces to about 452.4 m/s at hydraulic pump pressure of 30 MPa or confining stress of 10.6 MPa. Micro cracks could be observed near the crack path and the crack tip when the rock plate subjected to hydraulic compression and dynamic loading. Therefore, DIC method combined with ultra-high speed photography could be used to study the dy amic r ck fracture u der c nfining stress, which provides a new method for high spe d fail re investigatio of nderground rock that con er ed in geophysics and geoengineering applic tion. ECF22 - Loading and Environmental effects on Structural Integrity Fracture behavior of rock plate under static and dynamic combined loads Guiyun Gao* Institute of Crustal Dynamics, China Earthquake Administration, Beijing 100085, China Abstract It is critical to understand the dynamic fracture and crack prop ga ion of confined rocks in geophysics and geoengineering application, such as earthquake fault rupture and in-situ stress measurement. The objective of this paper is to characteriz the dynamic fracture behavior of rock plate especially under uniaxial compression using the DIC method combined with ultra-high speed photography. Using a modified hydrauli pump, the uniaxial co pression was exerted at the top and bottom ends of the rock plate. Dynamic crack propagation tests of plate specimen were conducted using split Hopkinson ressure bar (SHPB) and the fracture processes were captured by an ultra-high speed photography. Th displacem nt and strai field f the dynamic fractur process were calculated using DIC. By setting the virtual digital extensometer, the rack-tip position, crack propagation velocity and the dynamic fra ture to ghness were obtained. Results show that the fr acture toughness increases from 1.39 MPa∙m 1/2 to 2.25 MPa∙m 1/2 , and the crack propagation velocity incr ases from 843.6 m/s to 1148.3 m/s whe the incident velocity increases from 8.95m/s to 19.3m/s. The crack propagation velocity is higher than that obtained from small specime such as NSCB specim n (Gao et al., 2015). Crack propagation velocity in rock plate is igher than that in small specimen such as notched semi-circular bending (NSCB) specimen of rock. There is one main crack path under lower gas pressure, while crack bifurcati n occurs under high loa i pressure. Crack propagation v locity and crack arrest length decrease with the increase of the hydraulic compressive pressure. If the late is free of confining stress before dynamic loading, the crack propagation velocity is about 965.0 m/s. The crack propagation velocity d creases with the increase of hydr uli confi ing stress, and it reduces to about 452.4 m/s at hydraulic pump pressure of 30 MPa or confining stress of 10.6 MPa. Micro cracks could b observed near the crack path and the cr ck tip when th rock plate subjected to hydraulic compression and dynamic l ading. Therefore, DIC m thod combined with ultra-high speed photography could be sed t study the dynamic rock fr c ure under confining s r ss, w ic provides a new method f r high s eed failure investigation of underground ock that concerned in geophy ics a d eoengineering application. Abstract

© 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 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 the ECF22 organizers.

Keywords: High Pressure Turbine Blade; Creep; Finite Element Method; 3D Model; Simulation. Keywords: combined load, crack propagation v locity, fracture toughness, rock plate, dig tal image correlation; Keywords: combined load, crack propagation velocity, fracture toughness, rock plate, digital image correlation;

* 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. * Corresponding author. Tel.: +86-15120055150; fax: +86-010-62846130. E-mail address: gygaopku@163.com * Corresponding author. Tel.: +86-15120055150; fax: +86-010-62846130. E-mail ad ress: gygaopku@163.com

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.2018.12.009