PSI - Issue 13

ScienceDirect Available online at www.sciencedirect.com Av ilable o line at www.sciencedire t.com ScienceDirect Structural Integrity Procedia 00 (2016) 000 – 000 Procedia Structu al Integrity 13 (2018) 566–57 Available online at www.sciencedirect.com ScienceDirect Structural Integrity Procedia 00 (2018) 000 – 000 Available online at www.sciencedirect.com ScienceDirect Structural I tegrity 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. ECF22 - Loading and Environmental effects on Structural Integrity Quantifying the Deleterious Effect of Sea Water on the Fatigue Life of Welded Steel Joints Using a Fracture-Mechanics Approach Adam Smith a, *, Mark Knop a a Defence Science and Technology, 506 Lorimer Street, Fishermans Bend, VIC 3207, Australia Numerous studies have been conducted to investigate he deleterious effect of ea wat r on the fatigue life of welded joints f r offshore structures subjected to wave loading (0.15 Hz to 0.5 Hz). In contrast, little research has been conducted to quantify this effect on the fatigue life of marine structures subjected to lower cycle frequencies. In the present study, a fracture-mechanics based approach in conjunction with the finite-element method has been used to model fatigue tests carried out on tee-butt welded joints in aqueous 3.5 wt.% NaCl (an analogue for sea water) under freely corroding conditions and various cycle frequencies (from 1 Hz to < 0.001 Hz) subjected to a constant stress range. This type of analysis can now be carried out because a more comprehensive corrosion-fatigue crack-growth-rate dataset for these low cycle frequencies has recently been published. Fatigue cracking in tee-butt welded joints was successfully odelled, and the results of this modelling, which are consistent with corrosion-fatigue crack-growth rates, indicate that the fatigue life of these tee-butt welded joints can be reduced by up to about 6.7 times in a salt-water environment for very low cycle frequencies (< 0.001 Hz) compared with th fatigue life in air. © 2018 The Authors. Published by Elsevier B.V. Peer-review und r responsibility of the ECF22 organizers. Keywords: fatigue; sea w ter; steel; t e-butt welds; fatigue-life; fracture-mechanics; 1. Introduction The environmental reduction factor (ERF) on the fatigue life of a welded joint is the number of cycles-to-failure in air, N f , divided by the number of cycles-to-failure in a deleterious environment (typically sea water or an equivalent aqueous enviro ment), N f(E) . It can b used in conjunction with stress-range – versus – cycles-to-failure (S-N) data for specimens tested in air to predict the fatigue life of welded joints in a marine environment. The UK © 2018 The Authors. Published by Elsevier B.V. Peer-review under responsibility of the ECF22 organizers. ECF22 - Loading and Environmental effects on Structural Integrity Quantifying the Deleterious Effect of Sea Water on the Fatigue Life of Welded Steel Joints Using a Fracture-Mechanics Approach Adam Smith a, *, Mark Knop a a Defence Science and Technology, 506 Lorimer Street, Fishermans Bend, VIC 3207, Australia Abstract Numerous studies have been conducted to investigate the deleterious effect of sea water on the fatigue life of welded joints for offshore structures subject d to wave loading (0.15 Hz to 0.5 Hz). In ntrast, little res arch has been conducted to quantify this effect on the fatigue lif of marine structures subjected to lower cycle frequenci s. In the present study, a fracture-mechanic based approach in conjunction with the finite-element method has been used to model fatigue tests carried out on tee-butt welded joints in aqueous 3.5 wt.% NaCl (an analogue for sea water) under freely c rroding conditions and vari s cycl frequenci s (from 1 Hz to < 0.001 Hz) subjected to constant stress range. This type of analysis can n w be carried out because a more comprehensive corrosion-fatigu crack-growth-r te dataset for these low cycle frequencies has rec ntly been pu lished. Fatigu racking in tee-butt welded joints was successfully modelled, and the results of this modelling, which are consistent with orrosion-fatigue crack-growth rates, indicat that the fatigu life of these te -butt welded j ints can be reduc d by up t about 6.7 times in a salt-w te environme t for very low cycle frequencies (< 0.001 Hz) compare with the atigue lif in air. © 2018 The Authors. Published by Elsevier B.V. Peer-review und r responsibility of the ECF22 organizers. Keywords: fatigue; sea water; steel; tee-butt elds; fatigue-life; fracture-mechanics; 1. Introduction The environmental reduction factor (ERF) on the fatigue life of a welded joint is the number of cycles-to-failure in air, N f , divi d by the number of cycles-t -failur in a deleterious environment (typically sea water or an equivalent aqueous environment), N f(E) . It can be used in conjunction with stress-range – versus – cycles-to-failure (S-N) data for specimens tested in air to predict the fatigue life of welded joints in a marine environment. The UK © 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. Abstract

* Corresponding author. Tel.: +351 218419991. E-mail address: amd@tecnico.ulisboa.pt 2452-3216 © 2018 The Authors. Published by Elsevier B.V. Peer-review under responsibility of the ECF22 organizers. 2452-3216 © 2018 The Authors. Published by Elsevier B.V. Peer review under r sponsibility of the ECF22 o ganizers. * Corresponding author. Tel.: +613 9626 8327; fax: +613 9626 8341. E-mail address: adam.smith@dst.defence.gov.au * Corresponding author. Tel.: +613 9626 8327; fax: +613 9626 8341. E-mail ad ress: adam smith@dst.defence.gov. u

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 ECF22 organizers. 10.1016/j.prostr.2018.12.093