PSI - Issue 11

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ScienceDirect Available online at www.sciencedirect.com Av ilable o line at ww.sciencedire t.com ScienceDirect Structural Integrity Procedia 00 (2016) 000 – 000 Procedia Structu al Integrity 11 (2018) 194–2 1 Available online at www.sciencedirect.com ScienceDirect Structural Integrity Procedia 00 (2018) 000–000 Available online at www.sciencedirect.com ScienceDirect Structural Integrity 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. XIV International Conference on Building Pathology and Constructions Repair – CINPAR 2018 Monotonic and low-cycle fatigue properties of earthquake-damaged New Zealand steel reinforcing bars. The experience after the Christchurch 2010/2011 ea thq akes Giuseppe Loporcaro a , Alberto Cuevas a , Stefano Pampanin b,a , Milo V. Kral a a University of Canterbury, 20 Kirkwood avenue, Christchurch 8041, New Zealand b Sapienza University of Rome, Piazzale Aldo Moro 5, Rome 00185, Italy The 2010 and 2011 Christchurch seismic events have highlighted the limitations of the current knowledge in assessing the residual capacity of earthquake-damaged reinforced concrete (RC) buildings. An important challenge during the assessment phase was determining the residual ductility and the remaining low-cycle fatigue life of damaged rebars. Low-cycle fatigue is a possible failure mechanism of steel reinforcing bars when subjected to large-amplitude cyclic loads, such as due to earthquakes. While a single seismic event may not cause rebar failure, the low-cycle fatigue life will be reduced due to plastic strain. Also, New Zealand (NZ)-manufactured Grade 300E is prone to strain ageing. This phenomenon causes a change in mecha ical properties, such as increase in yield and ultimate t nsile strength, return of a discontinuous yield point, reduction in ductility and rise in the ductile/brittle trans tion temperature, and must be considere in damage asse sment. This paper discusse the effects of strain ageing on the monotonic and cyclic steel mechanical properties. Low-cycl fatigue tests were conducted on Grade 300E teel rebars. Reinforcing b r sampl s were subject d to constant and fully-reversed strain amplitud cycles. Strain amplitudes ranged from 0.5% to 3%. T strain-fatigue life curve for the un-aged steel was determined. The strain ageing effects on the f tigue life of Grade 300E were t en investigated. Specimens were cyclically test up to the 33% and 66% fatigue life previously determined and “artificially” aged at 100°C. Finally, they were cyclically tested until failure. The experimental data were analyzed and low-cycle fatigue models were calibrated using the Coffin-Manson empirical relationship. Fatigue lives of the un-aged and aged samples were then compared. Preliminary observations suggested that strain ageing triggers a premature crack initiation which propagates until failure. XIV International Conference on Building Pathology and Constructions Repair – CINPAR 2018 Monotonic and low-cycle fatigue properties of earthquake-damaged New Zealand steel reinforcing bars. The experience after the Christchurch 2010/2011 earthquakes Giuseppe Loporcaro a , Alberto Cuevas a , Stefano Pampanin b,a , Milo V. Kral a a University of Canterbury, 20 Kirkwood avenue, Christchurch 8041, New Zealand b Sapienza U iversit of Rome, Piazz l Aldo Moro 5, Rome 00185, Italy Abstract The 2010 and 2011 Christchurch seismic events have highlighted the limitations of the current knowledge in assessing the residual capacity of earthquake-damaged reinforc d concrete (RC) buil ings. An important chall ge during the as es ment phase w s determining the residual ductility a d th remaining low-cycle fatigue life of d maged rebars. Low-cycle fatigu is a possible failure mechanism of steel reinforci g bars when subjected to large-amplitude cyclic loads, such as due to e rthquakes. While a single seismic event may not cause rebar failure, the low-cycle f ti ue life will be reduced ue to pl tic strain. Also, N w Zealand (NZ)-manufa tur d Grade 300E is prone to strain ageing. This phenomenon causes a change in mechanical properties, such as increase in yield and ultimate tensile strength, return of a disco tin ous yi ld point, reduction in du tility and rise in the ductile/brittle tra sition temperature, and must be considered in da age assessment. This pap r discusses the ffects of str in ageing on the m notonic and cyclic ste l mechanical r perties. Low-cycle fatigue tes s were conducted on Grade 300E steel eb rs. Reinforcing bar s mples were subj ct d to onstant and fully-reversed strain ampli ude cycl s. Strain amplitudes ranged from 0.5% to 3%. The st ain-fatigue life curve for the un- ged steel was d t rmined. The strain ageing effects on the fatigue life of Grade 300E were then investigat d. Specimens were cyclically tested up o the 33% and 66% fatigue lif previously determin d and “artificially” aged at 100°C. Finally, they were cyclically tested until failure. The experim ntal data were analyzed and low-cycle fatigue mode s were calibrated using he Coffin-Manson empirical relationship. Fatigue lives of the un-aged and aged samples were then compa d. Preliminary observations suggested that st ain ageing triggers a pr mature crack i itiation which propagates until failure. © 2016 The Authors. Published by Elsevier B.V. Peer-review under responsibility of the Scientific Committee of PCF 2016. Copyright © 2018 Elsevier B.V. All rights reserved. Peer-review under responsibility of the CINPAR 2018 organizers Keywords: High Pressure Turbine Blade; Creep; Finite Element Method; 3D Model; Simulation. Copyright © 2018 Elsevier B.V. All rights reserved. Peer-review under responsibility of the CINPAR 2018 organizers Copyright © 2018 Elsevier B.V. All rights reserved. Peer-review under responsibility of the CINPAR 2018 organizers Keywords: earthquake damage; residual ductility; steel reinforcement; low-cycle fatigue, strain ageing Abstract

Keywords: earthquake damage; residual ductility; steel reinforcement; low-cycle fatigue, strain ageing

* Corresponding author. Tel.: +351 218419991. E-mail address: amd@tecnico.ulisboa.pt 2452-3216 Copyright © 2018 Elsevier B.V. All rights reserved. Peer-revi w u er responsibility of the CINPAR 2018 organizers. 2452-3216 Copyright © 2018 Elsevier B.V. All rights reserved. Peer-review under responsibility of the CINP R 2018 organizers.

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