PSI - Issue 2_B

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) 3177–3184 Available online at www.sciencedirect.com ScienceDirect StructuralIntegrity Procedia 00 (2016) 000 – 000 Available online at www.sciencedirect.com ScienceDirect StructuralIntegrity Procedia 00 (2016) 000 – 000

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21st European Conference on Fracture, ECF21, 20-24 June 2016, Catania, Italy 21st European Conference on Fracture, ECF21, 20-24 June 2016, Catania, Italy

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. Low Cycle Fatigue Behaviour of Ex-Service P92 Steel at Elevated Temperature N.A.Alang a,b, *,C.M.Davies a , K.M.Nikbin a a Department of Mechanical Engineering, Imperial College London, SW7 2AZ, London, United Kingdom b Faculty of Mechanical Engineering, University of Malaysia Pahang, 26600, Pahang, Malaysia The influence of strain amplitude and strain rate on low cycle fatigue (LCF) behaviour of the ex-service P92 steel at temperature of 600°C has been examined. Fully reversed strain-controlled LCF tests were conducted at the strain amplitude between ±0.4% and ±0.8% employing strain rate of 2.4x10 -3 s -1 to 2.4x10 -5 s -1 . The material has been found to exhibit continuous cyclic softening behaviour throughout the LCF tests, and there was no saturation stage observed. The number of cycles to failure decreased with lowering the strain rate and increasing strain amplitude. Mathematically, the relationship between time to failure and strain rate can be expressed by a power law relation. Elastic-plastic finite element (FE) analysis was carried out to obtain the hysteresis loop and cyclic str ss response of the material. The computation results shown to be in good agreement with the experimental ata. Fractogr phic xaminations of the fatigued specimens were perf rmed using scanning electron microscop (SEM). Under the LCF conditio at higher stra n rat s, the crack propagated int rgranularly which due to fatigue while at lower strain ra es the crack may be propagated in both inter- and transgr nular manner. © 2016 The Authors. Published by Elsevier B.V. Peer-review under responsibility of the Scientific Committee of ECF21. Keywords: Cyclic softening; low cycle fatigue; P92 steel; strain rate Low Cycle Fatigue Beh viour of Ex-Service P92 Steel at Elevated Temperature N.A.Alang a,b, *,C.M.Davies a , K.M.Nikbin a a Department Imperial C llege London, SW7 2AZ, London, United Kingdom b Faculty of Mechanical Engineering, University of Malaysia Pahang, 26600, Pahang, Malaysia Abstract The influence of strain amplitude and strain ra e o l w cycle fatigue (LCF) behaviour of the ex-service P92 steel at temperature of 60 °C has been examined. Fully reversed strain-controlled LCF tests were conducted a the strain amplitude between ±0.4% and ±0.8% employing strain ra of 2.4x10 -3 s -1 to 2.4x10 -5 s -1 . The material has been fo nd to exhibit continuo s cyclic softening behaviour throughout the LCF t st , and there was no satur ion s age observed. The num r of cycles t fail re decreased wi h lowering th train r te and increasing strain amplitude. Ma h matically, the re ationship between ime to failur and stra n rate can be expressed by a p wer law relation. Elastic-plastic finit element (FE) analys s was c rri d out to obtain th hyst resis loop and cycl c stress respons of the mater al. he computation r sul s are shown to be i go d agreement with the xperimental data. Fractographic examinations of th fatigued specimens were p formed using scanning electron microsc py (SEM). Und r LCF condition at higher strain rates, the crack propagated i tergranula ly whi h due to fa igue while at lower strain rates the cra k m y be propagated in both inter- and transgranular manner. © 2016 The Authors. Published by Elsevier B.V. Peer-review under responsibility of the Scientific Committee of ECF21. Keywords: Cyclic softening; low cycle fatigue; P92 steel; strain rate 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. Abstract

© 2016 The Authors. Published by Elsevier B.V. Peer-review under responsibility of the Scientific Committee of PCF 2016. 1. Introduction 1. Introduction

Keywords: High Pressure Turbine Blade; Creep; Finite Element Method; 3D Model; Simulation. Due to the excellent mechanical and creep resistant properties, Grade 92 steel is extensively used as super-heater tubes and steam pipes in power plant. Such components may experience rather complex loading at constant and/or Due to the excellent mechanic l and creep resista properties, Grade 92 steel is extensively used as super-heater tubes and steam pipes in power plant. Such components may experience rather complex loading at constant and/or

* N.A.Alang. Tel.: +44-740-439-7148. E-mail address: naa13@imperial.ac.uk * N.A.Al ng. Tel.: +44-740-439-7148. E-mail address: naa13@imperial.ac.uk

* 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 Elsev er B.V. Peer-review un r 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.2016.06.396