PSI - Issue 2_A

ScienceDirect Available online at www.sciencedirect.com Av ilable o line at ww.sciencedire t.com cienceDirect Structural Integrity Procedia 00 (2016) 000 – 000 Procedia Struc ural Integrity 2 (2016) 1797–18 4 Available online at www.sciencedirect.com Structural Integrity Procedia 00 (2016) 000–000 Available online at www.sciencedirect.com 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. 21st European Conference on Fracture, ECF21, 20-24 June 2016, Catania, Italy A Photo lastic Study for Multiparametric Analysis of th Near Crack Tip Stress Field Under Mixed Mode Loading Stepanova Larisa a , Roslyakov Pavel b , Lomakov Pavel c a Samara State University, Akad. Pavlov 1, Samara 443011, Russia b Samara State University, Akad. Pavlov 1, Samara 443011, Russia, JSC ”SRC Progress”, Zemetsa str. 18, Samara 443009 c Samara State University, Akad. Pavlov 1, Samara 443011, R sia Abstract The study is aimed at theoretical, experimental and computational determination of the coe ffi cients in crack tip asymptotic expan sions for a wide class of specimens under mixed mode loading c onditions. Multiparametric presentation of the stress file d near the crack tips for a wide class of specimens is given. Theoretical, experimental and computational results obtained in this research show that the isochromatic fringes in the vicinity of the crack tip require to keep the higher order stress terms in the asymptotic expansion of the stress field around the crack tip since the co ntribution of the higher order stress terms (besides the stress intensity factors and the T-stress) is not negligible in the crack tip s tress field. One can see that the higher order terms of the asym ptotic expansion are important when the stress distribution has to be known also farther from the crack tip and it is necessary to extend the domain of validity of the Williams solution. It is shown that at large distances from the crack tips the e ff ect of the higher order terms of the Williams series expansion becomes more considerable. The knowledge of more terms of the stress asymptotic expansions will allow us to approximate the stress field near the crack ti ps with high accuracy. c � 2016 The Authors. Published by Elsevier B.V. Peer-revi w under responsibility of th Scientific Committ ee of ECF21. Keywords: Photoelasticity, Mixed Mode Loading; Higher order terms; Asymptotic analysis; Multiparametric presentation of the s tress field near the crack tip, Williams series expansion 21st European Conference on Fracture, ECF21, 20-24 June 2016, Catania, Italy A Photoelastic Study for Multiparametric Analysis of the Near Crack Tip Stress Field Under Mixed Mode Loading Stepanova Larisa a , Roslyakov Pavel b , Lomakov Pavel c a Samara State University, Akad. Pa lov 1, Samara 443011, Russia b Samara State University, Akad. Pavlov 1, Samara 443011, Russia, JSC ”SRC Progress”, Zemetsa str. 18, Samara 443009 c Samara State University, Akad. Pavlov 1, Samara 443011, Russia Abstract The study is aimed at theoretical, experimental and computational determination of the coe ffi cients in crack tip asymptotic expan sions for a wide class of specimens under mixed mode loading c onditions. Multiparametric presentation f the stress file d near the crack tips for a wide class of specimens is given. Theoretical, experimental and computational results obtained in this research show that the isochromatic fringes in the vicinity of the crack tip require to keep the higher order stress terms in the asymptotic expansion of the stress field around the crack tip since the co ntribution of the higher order stress terms (besides the stress intensity factor and the T-stress) is not negligible in the crack tip s tress field. One can see that the higher order terms of the asym ptotic expansion are important when the stress distribution has to be known also farther from the crack tip and it is necessary to extend the domain of validity of the Williams solution. It is shown that at large distances from he crack t ps the e ff ect of the higher order terms of the Williams series expansion ecomes more considerable. The knowledge of more terms of the str ss asymptotic expansions will allow us to approximate the stress field near the crack ti ps with high accuracy. c � 2016 The Authors. Published by Elsevier B.V. Peer-review under responsibility of the Scientific Committ ee of ECF21. Keywords: Photoel sticity, Mixed Mode Loading; Higher ord r terms; Asymptotic analysis; Multip rametric p sentation of the s tre s fie d n ar the crack tip, Williams eries expansion Copyright © 2016 The Authors. Published by Elsevier B.V. This is an open access article u der the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/). P review under esponsibility of the Scient fic Committee of ECF21. Keywords: High Pressure Turbine Blade; Creep; Finite Element Method; 3D Model; Simulation. 1. Introduction. Review of advances in photoelasticity in fracture mechanics analysis Photoelasticity is a nondestructive, whole-field, graphic stress-analysis technique based on an optomechanical property called birefringence, possessed by many transparent polymers. Combined with other optical elements and illuminated with an ordinary light source, a loaded photoelastic specimen (or photoelastic coating applied to an or dinary specimen) exhibits fringe patterns that are related to the di ff erence between the principal stresses in a plane normal to the light propagation direction (Ayatollahi et al. (2011), Surendra and Simpa (2013)). Photoelasticity is a nondestructive, whole-field, graphic stress-analysis technique based on an optomechanical property called birefringence, possessed by many transparent polymers. Combined with other optical elements and illuminated with an ordinary light source, a loaded photoelastic specimen (or photoelastic coating applied to an or dinary specimen) exhibits fringe patterns that are related to the di ff erence between the principal stresses in a plane normal to the light propagation direction (Ayatollahi et al. (2011), Surendra and Simpa (2013)). © 2016 The Authors. Published by Elsevier B.V. Peer-review under responsibility of the Scientific Committee of PCF 2016. 1. Introduction. Review of advances in photoelasticity in fracture mechanics analysis

* Corresponding author. Tel.: +351 218419991. E-mail address: amd@tecnico.ulisboa.pt ∗ Stepanova L.V.. Tel.: + 7-842-334-5441 ; fax: + 7-846-334-5417. E-mail address: stepanovalv@samsu.ru ∗ Stepanova L.V.. Tel.: + 7-842-334-5441 ; fax: + 7-846-334-5417. E-mail address: stepanovalv@samsu.ru

2452-3216 © 2016 The Authors. Published by Elsevier B.V. Peer-review under responsibility of the Scientific Committee of PCF 2016. Copyright © 2016 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 ECF21. 10.1016/j.prostr.2016.06.226 2452-3216 c � 2016 The Authors. Published by Elsevier B.V. Peer-review under responsibility of the Scientific Committ ee of ECF21. 2452-3216 c � 2016 The Authors. Published by Elsevier B.V. Peer-review under responsibility of the Scientific Committ ee of ECF21.