PSI - Issue 1

ScienceDirect Procedia Structural Integrity 1 (2016) 002–009 Available online at www.sciencedirect.com Av ilable o line at ww.sciencedire t.com Sci ceDirect Structural Integ ity Procedia 00 (2016) 00 – 000 Available online at www.sciencedirect.com ScienceDirect Structural Integrity Procedia 00 (2016) 000–000 Available online at www.sciencedirect.com ScienceDirect Structural Integrity Procedia 00 (2016) 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. XV Portuguese Conference on Fracture, PCF 2016, 10-12 February 2016, Paço de Arcos, Portugal High-cycle fatigue of notched plain concrete Luca Susmel a * a Department of Civil and Structural Engineering, The University of Sheffield, Mappin Street, Sheffield S1 3JD, United Kingdom Abstract This paper investigates the accuracy of the so-called Theory of Critical Distances (TCD) in modelling, in the high-cycle fatigue regime, the behaviour of notched plain concrete. The TCD postulates that the fatigue damage extent has to be estimated by directly post-processing the entire linear-elastic stress field damaging the material in the vicinity of the crack initiation locations. According to the TCD’s modus operandi, the high-cycle fatigue assessment is performed by using a scale length parameter which is treated as a material property. The accuracy of this method was checked against a number of experimental results generated by testing, under four-point bending, notched specimens of plain concrete. This validation exercise allowed us to prove that the TCD is successful in estimating the high-cycle fatigue strength of notched concrete beams, resulting in predictions falling within an error interval of about ±15%. © 2016 The Authors. Published by Elsevier B.V. Peer-review under responsibility of the Scientific Committee of PCF 2016. Keywords: plain concrete, fatigue, notch, Theory of Critical Distances 1. Introduction In situations of practical interest concr te s ructures can undergo in-service tim -variabl loading. This is a co mon situation, for instance, in runways subjected to rep ated loads due to passing aircrafts, asphalt concretes subjected to cyclic local pressures resulting from the action of tyres, and the concrete structural parts of bridges cyclically loaded by traveling motor vehicles. Even though, since the beginning of the last century (Von Ornum, 1903; Von Ornum, 1907) a tremendous effort has been made by the international scientific community, examination of the state of the art shows that a universally accepted strategy suitable for efficiently perform the fatigue assessment of concrete has not been agreed yet. Further, other than a few isolated investigations (Ohlsson et al., XV Portuguese Conference on Fracture, PCF 2016, 10-12 February 2016, Paço de Arcos, Portugal High-cycle fatigue of notched plain concrete Luca Susmel a * a Department of Civil and Structural Engineering, The University of Sheffield, Mappin Street, Sheffield S1 3JD, United Kingdom Abstract This paper investigates the ac uracy of the so-called Theory of Critical Distances (TCD) in modelling, in the high-cycle fatigue regime, the behaviour of notched plain concrete. The TCD postulates that the fatigue damage ext nt has to be estimated by directly post-processing the entire linear-elastic stre s field dam ging the material in the vicinity of the crack initi tion locations. According to the TCD’s modus operandi, the high-cycle fatigue assessment is performed by using a scale length parameter which is treated as a material property. The accuracy of thi method was checked ag inst a number of experimental results generated by testing, under four-point bending, notched specimens of plain c n r te. This validation exercise allowed us t prove that the TCD is successful in estimating the high-cycle fatigue strength of notched concrete beams, resulting in predictions falling within an error interval of about ±15%. © 2016 The Autho s. Published by Elsevier B.V. Peer-review under responsibility of the Scientific Committee of PCF 2016. Keywords: plain concrete, fatigue, notch, Theory of Critical Distances 1. Introduction In situations of practic l interest concrete structures can und rgo in-s rvice time-v iable lo ding. This is a common situation, f r instance, in unways subjec ed to repeated loads ue to passing ai crafts, asphalt concret subje ted t cyclic local pressures esult ng from the action of tyres, and the concret structural parts of b idges cyclically loaded by traveling otor vehicles. Even though, since the begin ing of the last century (Von Ornum, 1903; Von Ornum, 1907) a tremendous effort h s been made by the international sci ntif c community, examination of the sta e of the art shows that a universally acc pted st a egy suitable for effici ntly perform the fa igue assessment of concrete has not been agreed yet. Further, other than a few isolated investigations (Ohlsson et al., Copyright © 2015 The Authors. Published by Elsevier B.V. This is an open access article un er the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/). Peer-review under responsibility of the Scientific Committee of PCF 2016. © 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 © 2016 The Authors. Published by Elsevier B.V. Peer-review under responsibility of the Scientific Committee of PCF 2016. 2452-3216 © 2016 The Authors. Published by Elsevier B.V. Peer-review under responsibility of the Scientific Committee of PCF 2016. * Corresponding author. Tel.: +44 (0) 114 222 5073; fax: +44 (0) 114 222 5700. E-mail address: l.susmel@sheffield.ac.uk * Corresponding author. Tel.: +44 (0) 114 222 5073; fax: +44 (0) 114 222 5700. E-mail address: l.susmel@sheffield.ac.uk

2452-3216 © 2016 The Authors. Published by Elsevier B.V. Peer-review under responsibility of the Scientific Committee of PCF 2016. Copyright © 2015 The Authors. Published by Elsevier B.V. This is an open access article under the CC BY-NC-ND license ( http://creativecommons.org/licenses/by-nc-nd/4.0/ ). Peer review under responsibility of the Scientific Committee of PCF 2016. 10.1016/j.prostr.2016.02.002