PSI - Issue 13

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 Structural Integrity 13 8 69–73 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. ECF22 - Loading and Environmental effects on Structural Integrity Assessment of fatigue crack growth behavior of cracked specimens repaired by indentation S.M.J. Razavi a, *, M.R. Ayatollahi b , F. Berto a a Department of Mechanical and Industrial Engineering, Norwegian University of Science and Technology (NTNU), 7491 Trondheim, Norway. b School of Mechanical Engineering, Iran University of Science and Technology, Narmak, 16846, Tehran, Iran. The indentation technique has been widely studied as a technique for fatigue crack growth retardation. However, the majority of the researches are limited only to crack tip indentation technique. The aim of current research is to investigate the effect of three different methods of indentation on the fatigue crack growth life of the pre-cracked specimens. Fatigue tests were performed on a group of specimens repaired by crack tip indentation using various indentation loads and the results were compared with the samples repaired by the double indentation and triple indentation methods. The experimental results revealed that the higher indentation loads results larger domain of compressive residual stress at the vicinity of the crack tip and consequently improve the fatigue crack growth life of the pre-cracked specimen. Additionally, the locatio of the indentation plays an importa t ole the efficiency of this method. For he sp cimens repaired by double and triple indentation methods, i enti g ahead of the crack tip led to retardation in more crack growth compared t the other horizontal positions of indentation. The tripl indentation technique which was pr posed in this research provided higher f tigue crack growth retardation compar d to single and double indentation methods. © 2018 The Authors. Published by Elsevier B.V. Peer-review under responsibility of the ECF22 organizers. Keywords: crack retardation; fatigue crack growth; fatigue damage repair; residual stress 1. Introduction The fatigue lif of cracked compon nts can b extended using numero s method, which have been widely studied in the past (Domazet, 1996; Shin and Cai, 2000; Ayatollahi et al., 2014; Razavi et al., 2017). As an efficient method © 2018 The Authors. Published by Elsevier B.V. Peer-review under responsibility of the ECF22 organizers. ECF22 - Loading and Environmental effects on Structural Integrity Assessment of fatigue crack growth behavior of cracked specimens repaired by indentation S.M.J. Razavi a, *, M.R. Ayatollahi b , F. Berto a a Department of Mechanical and Industrial Engineering, Norwegian University of Science and Technology (NTNU), 7491 Trondheim, Norway. b School of Mecha ical Engineering, Iran University of Science and T chnology, Narmak, 16846, Tehran, Ira . Abstract The indentation technique has been widely studied as a technique for fatigue crack growth retardation. However, the majority of the res arches re limited only to crack tip indentation technique. The aim of c rrent research is to investigate the effect of three different methods of indentation on the f tigue crack gr wth life of the pre-cracked specim ns. Fatigue tests were per ormed on a group of sp cimens repaired by crack tip indentation using various indentation loads and the re ults wer compar d with the samples repaired by the double indentation and triple indentatio methods. Th experimental results vealed that the higher indentation loads results larger domain of compressive residual stress at the vicinity of the crack tip and consequ ntly improve the fatigu cr ck gr wth life of the p e-cracked specimen. Additionally, the location of the indentation plays an important role in the fficiency of this method. For the sp cimens repaired by double and triple indent ti met ods, i denti g ahead of the crack tip led to retardation in more crack growth compar d to the other horizontal positions of indentation. The triple indentation technique which was proposed in this researc provided higher fatigue crack growth retardation comp red to single and double indentation methods. © 2018 The Authors. Published by Elsevier B.V. Peer-review under esponsibility of the ECF22 organizers. Keywords: crack retardation; fatigue crack growth; fatigue damage repair; residual stress 1. Introduction The fatigue life of cracked components can be extended using numerous method, which have been widely studied in the past (Domazet, 1996; Shin and Cai, 2000; Ayatollahi et al., 2014; R zavi et al., 2017). As an effici nt metho © 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.: +47-735-93761. E-mail address: javad.razavi@ntnu.no * Corresponding author. Tel.: +47-735-93761. E-mail ad ress: javad razavi@ntnu.no

* 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.

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.2018.12.012