PSI- Issue 9

ScienceDirect Available online at www.sciencedirect.com Available o line at ww.sciencedire t.com ScienceDirect Structural Integrity Procedia 00 (2016) 000 – 000 P o edi Structural Integr ty 9 (2018) 29–36 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. © 2018 The Authors. Published by Elsevier B.V. Peer-revi w und r responsibility of the Gruppo Italiano Frattura (IGF) ExCo. IGF Workshop “Fracture and Structural Integrity” On the fatigue strength of 3D-printed polylactide (PLA) O. H. Ezeh and L. Susmel* Department of Civil and Structural Engineering, The University of Sheffield, Mappin Street, Sheffield, S1 3JD, United Kingdom Abstract This paper aims to review quantitatively our understanding of the fatigue behavior of additively manufactured (AM) polylactide (PLA). A number of data sets were selected from the technical literature and statistically re-analyzed in terms of S-N curves to define a reference value both for the negative inverse slope and the endurance limit extrapolated at 2 · 10 6 cycles to failure. The experimental results being post-processed suggest that, as far as AM PLA is concerned, the mean stress effect in fatigue can be modelled by simply using the m ximum str ss in the cycle. Fu ther, sin e the printing irection appears to have little effect on the overall fatigue behavior of AM PLA, the stress/strength analysis can be performed effectively by treating this polymer as a homogenous, isotropic and linear-elastic material. According to the statistical re-analysis discussed in the present paper, when appropriate experimental results cannot be generated, the fatigue assessment (for a probability of survival larger than 95%) can be performed by using a reference fatigue curve with negative inverse slope equal to 5.5 and endurance limit (at 2 · 10 6 cycles to failure) equal to 10% of the material ultimate tensile strength. © 2018 The Authors. Published by Elsevier B.V. Peer-review under responsibility of the Gruppo Italiano Frattura (IGF) ExCo. Keywords: Additive manufacturing; polylactide (PLA); fatigue; design curve. 1. Introduction According to the definition given by ASTM Committee F42, Additive Manufacturing (AM) is “the process of joining materials to make objects from 3D-model data, usually layer upon layer, as opposed to subtractive manufacturing methodologies” . IGF Workshop “Fracture and Structural Integrity” On the fatigue strength of 3D-printed polylactide (PLA) O. H. Ezeh and L. Susmel* Department of Civil and Structural Engineering, The University of Sheffield, Mappin Street, Sheffield, S1 3JD, United Kingdom Abstract This paper ai s to review quantitativ y our understanding of the fatigu behavior of dditively manufac u ed (AM) polylactide (PLA). A number of data sets were sel cted from th technical literature and statistically re- nalyzed in terms of S-N c rves to define a reference value both for the negative inverse slope and the endurance limit xtrapolated at 2 · 10 6 cy les to failure. Th experimental resu ts being post-processed sugges that, as far as AM PLA is co cerned, the mean st ess effect in fatigue can b mode ed by simply using the maximum stre s in the cycle. Further, since the printing direction appears to have little effect on the overall fatigue behavior of AM PLA, the s ress/strength analysis can be performed effectively by treating this polymer as a hom genous, isotropic and linear-elas ic materi l. Accordin to th tatistical re-analysis discu sed in the present paper, when appr priate experimental r sults cannot be generated, the fatigue a sessment (f r a probability of survival larger than 95%) can be performed by using a ref rence fatigue curv with negative inverse slope equal to 5.5 and endurance limit (at 2 · 10 6 cycles to failure) equal to 10% of the material ultimate tensile strength. © 2018 The Autho s. Publ shed by Elsevier B.V. Peer-review under responsibility of the Gruppo Italiano Frattura (IGF) ExCo. Keywords: Additive manufacturing; polylactide (PLA); fatigue; design curve. 1. Introduction According to the definition given by ASTM Committee F42, Additive Ma uf cturing (AM) is “the process of joining materials t make objects from 3D-model data, usually layer upon layer, as opposed to subtractive manufacturing methodologies” . © 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.

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 Gruppo Italiano Frattura (IGF) ExCo. 10.1016/j.prostr.2018.06.007 * Corresponding author. Tel.: +351 218419991. E-mail address: amd@tecnico.ulisboa.pt 2452 3216 © 2018 Th Authors. Published by Elsevier B.V. Peer-review under responsibility of the Gruppo Italiano Frattura (IGF) ExCo. 2452-3216 © 2018 The Authors. Published by Elsevier B.V. Peer-review under responsibility of the Gruppo Italiano Frattura (IGF) ExCo. * Correspon ing 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