PSI - Issue 2_B

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) 1553–156 Available online at www.sciencedirect.com Sci nceDirect 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. 21st European Conference on Fracture, ECF21, 20-24 June 2016, Catania, Italy Master curv in upper gion of ductile brittle transition: a modification based on local damage approach Abhishek Tiwari a,b* , R. N. Singh a,b , Per Ståhle c , J. K. Chakravartty a a Mechanical Metallurgy Division, Bhabha Atomic Research Centre, Trombay, Mumbai, India 400085 b Homi Bhabha National Institute, Anushaktinagar, Mumbai, India 400094 c Division of Solid Mechanics, Lund University, SE 221 00 Lund, Sweden Abstract The fracture behaviour of ferritic/ferritic martensitic steels in Ductile to Brittle Transition (DBT) region is well captured by Master Curve approach, except in the upper region of transition due to ductile tearing prior to cleavage. The fracture toughness behavior in the upper region of DBT is generally censored by Master Curve. In this work the Master Curve approach is modified to extend its applicability to the upper region of transition. The ductile tearing in the upper region of transition, increased sampled volume and constraint increment are addressed in this work using constraint parameter T stress and numerical analyses using GTN damage. © 2016 The Authors. Published by Elsevier B.V. Peer-review under responsibility of the Scientific Committee of ECF21. Keywords: Master Curve; Local damage; ductile brittle transition; VUMAT; ABAQUS 1. Introduction The Master Curve (MC) approach models cleavage and assumes self-similarity of stress field at the crack front. This single fracture paramet r, KJC, based approach restricts its applicability to lower region of transition where insignificant amount of ductile tearing pr cedes cleavag . In upper region of transition, the increasing active volume comprises a part of volume ahead of crack tip, changing to plastic wake after ductile tearing and other which contributes to cleavage. The increment in constraint wit associated change in ligament length with Ductile Crack Growth (DCG) increases the number of potentially critical carbides for cleavage succeeding eventually in cleavage fracture. 21st European Conference on Fracture, ECF21, 20-24 June 2016, Catania, Italy Master curve in upper region of ductile brittle transition: a modification based on local damage approach Abhishek Tiwari a,b* , R. N. Singh a,b , Per Ståhle c , J. K. Chakravartty a a Mechanical Metallurgy Division, Bhabha Atomic Research Centre, Trombay, Mumbai, India 400085 b Homi Bhabha National Institute, Anushaktinagar, Mumbai, India 400094 c Division of Solid Mechanics, Lund University, SE 221 00 Lund, Sweden Abstract The fracture behaviour of ferritic/ferritic martensitic steels in Ductile to Brittle Transition (DBT) region is well captured by Master C ve approach, exc pt in the upper region of transition due to ductile t aring pri r to cleavage. The fracture to ghness behavior in the u per region of DBT is generally censored by Master Curve. In this work the Master Curve app oach is modified to extend its applicability to the upper region of transition. The ductile tearing in the upper region of transition, increased sampl volume nd constr int increment ar addressed in this work using constrai t parameter T stress and numerical analyses using GTN damag . © 2016 The Authors. Publishe by Elsevier B.V. Pe r-r view under es onsibili y of the Scientific Committee of ECF21. Keywords: Mast r Curve; L cal damage; uctile brittle transition; VUMAT; ABAQUS 1. Introduction The Master Curve (MC) approach models cleavage and assumes self-similarity of stress field at the crack front. This single fracture parameter, KJC, based approach restrict its applicability to l wer region of transition where ins gn ficant amount of ductile tearing precedes cleavag . In upper region of transiti n, the increasing active volum comp is s a part of v l me ah d of crack tip, ch nging to plastic wake after ductil tea ing and oth r which ntributes to cleavage. Th increment in onstraint with ass ciated hang in ligament length with Ductile Cra k Growth (DCG) increases t number of pote tially critical carb des for cleavage succ eding eventually in cleav ge fracture. 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. © 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 ECF21. 2452-3216 © 2016 The Authors. Published by Elsevier B.V. Peer-review under responsibility of the Scientific Committee of ECF21. * Corresponding author. Tel.: +91-2559-5304; fax: +91-22-25505151. E-mail address: abhishektiwari@daad-alumni.de * Corresponding author. Tel.: +91-2559-5304; fax: +91-22-25505151. E-mail address: abhishektiwari@da d-alumni.de

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.2016.06.197