PSI - Issue 13

ScienceDirect Available online at www.sciencedirect.com Available online at ww.sciencedire t.com cienceDirect Structural Integrity Procedia 00 (2016) 000 – 000 Procedia Structural Integrity 13 (2018) 1657–1662 Available online at www.sciencedirect.com ScienceDirect Structural Integrity Procedia 00 (2018) 000–000 Available online at www.sciencedirect.com ScienceDirect Structural I t grity 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 Peculiarities of bond strength degradation in reinforced concrete induced by accelerated electrochemical methods Myroslava Hredil* Karpenko Physico-Mechanical Institute of the National Academy of Sciences of Ukraine. 5 Naukova str., Lviv 79020, Ukraine Abstract Reinforced concrete (RC) structures are long-term operated objects with service life of 50–100 years. During their operation they subject to continuous ambient effects (cyclic temperature changes, acid rains, de-icing salts) and service loads (e.g. traffic) which effect on structural integrity of the composite and lead to worsening of structures serviceability. One of the reasons for strength loss of RC members is bond degradation between rebar nd concrete. It could be caused by two different factors: overprotection of RC and reinforcement corrosion. These effects were simulated in the laboratory conditions by the electrochemical methods, applying of impressed cathodic current and accelerated corrosion tests respectively. It was shown that applied node polarization causes not only concrete cracking due to internal pressure of corrosion products at the interface, but also due to their expansion far from rebar, for a distance comparative with a specimen thickness, evidently into preliminary formed cracks. Since intensive corrosion of steel reinforcement decreases its iameter and corrosion products can migrate from the rebar surface into a depth of concrete these factors could weaken bond in RC installations up to a total loss of cohesion between rebar and concrete. The influence of cathodic polarization of steel embedded in concrete is commonly seemed to consist in its possible hydrogen embrittlement and ions redistribution in concrete matrix. In this paper the effect of hydrogen recombined at the rebar–concrete interface on bond weakening and concrete cracking is considered. © 2018 The Authors. Published by Elsevier B.V. Peer-review under responsibility of the ECF22 organizers. Keywords: reinforced concrete, accelerated corrosion, impressed current, hydrogen charging, bond strength. © 2018 The Authors. Published by Elsevier B.V. Peer-review under responsibility f the ECF22 organizers. ECF22 - Loading and Environmental effects on Structural Integrity Peculiarities of bond strength degradation in reinforced concrete induced by accelerated electrochemical methods Myroslava Hredil* Karpenko Physico-Mechanical Institute of the National Academy of Sciences of Ukraine. 5 Naukova str., Lviv 79020, Ukraine Abstract Reinforced concrete (RC) structures are long-term operated objects with service life of 50–100 years. During their operation th y subj ct t continuous ambient effects (cyclic temperature changes, acid rains, de-icing salts) and service loads (e.g. traffic) which effect on structural integrity of the composite and lead to worsening of structures serviceability. On of the reasons for strength loss of RC members is bond d gradatio be ween rebar and co crete. It could be caused by two different factors: ov rprotection of RC and reinforcement corr sion. These effects were simulated in the laboratory conditio s by the electrochemical methods, applying of i pressed cathodic current and acc lerated corrosio tests respectively. It was shown that applied anode polarization causes n t only concrete cracking due to internal pressure f corrosion products at the interface, but lso due to their expansion far from rebar, for a distance comparative with a specimen thickness, evidently into preliminary formed cracks. Since i tensive corrosion of steel reinfor ment decreases its diameter a d corrosion products can migrate from the r bar surface into a depth of c ncrete these factors could w ak n bond in RC installations up to a total loss of cohesion betw en rebar and concr te. The influ nce of cathodic polarization of steel embedded in concrete is comm nly seem d to consist in its possible hydrogen mbrittlement and ions redistribution in concrete matrix. In this paper the effect of hydrogen recombi ed at the rebar–concrete interface o bond weak ning and concrete cracking is considered. © 2018 The Authors. Published by Elsevier B.V. Peer-review under responsibility of the ECF22 organizers. Keywords: reinforced concrete, accelerated corrosion, impressed current, hydrogen charging, bond strength.

© 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 © 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.: +380991939062; fax: +380322649427. E-mail address: mysya@ipm.lviv.ua * Corresponding author. Tel.: +380991939062; fax: +380322649427. E-mail ad ress: mysya@ipm.lviv.ua

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.2018.12.347