PSI - Issue 2_A

ScienceDirect Available online at www.sciencedirect.com Av ilable o line at ww.sciencedire t.com ienceDirect Structural Integrity Procedia 00 (2016) 000 – 000 Procedia Struc ural Integrity 2 (2016) 2631–2642 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. 21st European Conference on Fracture, ECF21, 20-24 June 2016, Catania, Italy C upl d FEM-DBEM Simulation of 3D Crack Growth under Fatigue Load Spectrum R. Citarella a , M. Lepore a , M. Perrella a , R.Sepe b *, G. Cricrì a a Dept. of Industrial Engineering, University of Salerno, via G. Paolo II, 132 - 84084 Fisciano, Italy. b Dept. of Industrial and Information Engineering, Second University of Naples, Via Roma, 29 - 81031 Aversa, Italy. Abstract Numerical predictions of fatigue crack growth under load spectrum are obtained by coupled FEM-DBEM approach. An initial part-through corner crack, in a pre-notched specimen undergoing a traction fatigue load, propagates becoming through the thickness. A two parameter crack growth law (“Unified Approach”) is calibrated by in house made constant amplitude experimen al tests and the crack growth retardation after an overload application is reproduced. The residual stresses responsible for such retardation are calculated by a sequence of elastic-plastic static FEM analysis; such stresses are then applied to the crack faces for the pro ag ti simulation in DBEM environm t. A satisfactory agreem nt between numerical and experimental crack growth rates are displayed, for both part-through crack and through the thickness crack. This approach provide general modeling capabilities, with allowance for general crack front shape and fully automatic propagation. © 2016 The Authors. Published by Elsevier B.V. Peer-review under responsibility of the Scientific Committee of ECF21. Keywords: Coupled FEM-DBEM, Load spectrum, Crack growth retardation, Residual stresses. 1. Introduction Damag Tolerance is used in the design of many ypes of structures, such as bridges, military ships, commercial aircraft, space vehicle and merchant ships. Damage tolerant design requires accurate prediction of fatigue crack growth under service conditions and typically this is accomplished with the aid of a numerical code. Many aspects of fracture mechanics are more complicated in practice than in two-dimensional laboratory tests, textbook examples, 21st European Conference on Fracture, ECF21, 20-24 June 2016, Catania, Italy Coupled FEM-DBEM Simulation of 3D Crack Growth under Fatigue Load Spectrum R. Citarella a , M. Lepore a , M. Perrella a , R.Sepe b *, G. Cricrì a a Dept. of Industrial Engineering, University of Salerno, via G. Paolo II, 132 - 84084 Fisciano, Italy. b Dept. of Industrial and Information Engineering, Second University of Naples, Via Roma, 29 - 81031 Aversa, Italy. Abstract Numerical predictions of fatigue crack growth under load spectrum are obtained by coupled FEM-DBEM approach. An initial part-through corner crack, in a pre-notched specimen undergoing tractio fatigue load, propagates becoming through the thickness. A two par meter crack growth law (“U ifie Approach”) is calibrated by in h use mad constan amplitud experimental tests and the crack growth re ard tion after an overload application is r produced. The residual stre ses responsibl for such re ardation are cal ulated by a sequence f elastic-plastic static FEM a alysis; such stresses are then applied to the crack aces for the propagation simulation in a DBEM environment. A satisfactory greement between numerical and experimental crack growth ates are displayed, for both part-through crack and through the hickness crack. This appro ch provid gener modeling capabilities, with allowanc for gene al c ack front sh pe and f lly automa ic propagation. © 2016 The Authors. Published by Elsevier B.V. Peer-review under responsibility of the Scientific Committee of ECF21. Keywords: Coupled FE -DBEM, Load spectrum, Crack growth retardation, Residual stresses. 1. Introduction Damage Tolerance is u ed in the design of many types of structures, such as bridges, military ships, commercial aircr ft, space v hi le and merchant ships. Damage tolerant design req ires accurate prediction of fatigue c ack growth under service co itions and typ cally this is accomplish d with the aid of a numerical c de. Many aspe ts of fracture mechani s are more complicated in practice than in two-dimensional laboratory tests, textbook ex m les, Copyright © 2016 The Authors. ublished by Elsevier B.V. This is an open access rticl 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.: +39-081-501-03-18. E-mail address: raffsepe@unina.it. * Corresponding author. Tel.: +39-081-501-03-18. E-mail address: raffsepe@unina.it.

* 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.

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.2016.06.329