PSI - Issue 2_B

ScienceDirect Available online at www.sciencedirect.com Av ilable o line at ww.sciencedire t.com cienceDirect Structural Integrity Procedia 00 (2016) 000 – 000 Procedia Structu al Integrity 2 (2016) 777–784 Available online at www.sciencedirect.com ScienceDirect Structural Integrity Procedia 00 (2016) 000 – 000 Available online at www.sciencedirect.com ScienceDirect Structural Integrity Procedia 00 (2016) 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. 21st European Conference on Fracture, ECF21, 20-24 June 2016, Catania, Italy Tw -paramete fracture characterization of a welded pipe in the presence of residual stresses S. Abolfazl Zahedi*, Andrey Jivkov School of Mechanical, Aerospace and Civil Engineering, The University of Manchester, Manchester, M13 9PL, UK In this paper two-parameter fracture characterization of elastic and elastic-plastic stress/strain field around a crack front is presented for a welded pipe component containing a circumferential through-thickness crack. A macro function programmed in PYTHON is used to compute the constraint parameters (T-stress, T z and Q factors) of the specimen in the open source finite element package Code_Aster. Data obtained from literature was employed to support three-dimensional finite element models developed in this research to study the impact of high magnitude repair-weld residual stresses. Complete distributions of the T stress, T z and Q-factors were obtained along a 3D crack front in the presence of residual stresses. The effects of stresses (residual and operational) on the constraint parameters are studied. It is shown that a two-parameter methodolo y provides effective characterization of three dimensional elastic – plastic crack tips constraint. © 2016 The Authors. Published by Elsevier B.V. Peer-review under responsibility of the Scientific Committee of ECF21. Keywords: constraint parameters; T-stress; T z -factor; Q-factor; residual stress 1. Introduction Residual stresses are present in most mechanical or thermal components due to the fabrication methodology, such as welding. They attract considerable attention in ngineering applications, because of their impact on part distortion, service performance and the costs associated with failures (Gannon et al., 2010). Therefore, it is necessary to understand the combined effect of mechanical loading and residual stresses on the fracture of structures in order to provide a more accurate structural integrity assessment. The prediction of crack initiation and propagation requires 21st European Conference on Fracture, ECF21, 20-24 June 2016, Catania, Italy Two-parameter fracture characterization of a welded pipe in the presence of residual stresses S. Abolfazl Zahedi*, Andrey Jivkov School of Mechanical, Aerospace and Civil Engineering, The University of Manchester, Manchester, M13 9PL, UK Abstract In this paper two-parameter fracture characterization of elastic and elastic-plastic stress/strain field around a crack front is presented fo a welded pip compon nt containing a circumferenti l through thickness crack. A macro function programmed n PYTHON is used to com ute the co strai paramete s (T-st ss, T z and Q factors) of the specimen in the pen source finite element packag C de_Aster. Data btained from li ature wa employed to support thr e-dimensional finite lement models d veloped in this research o study the impact f high magnitude repair-weld residual s resses. Complete d stributions of the T stress, T z and Q-factors were obtained along a 3D crack fro t in the resence of residual stre ses. The eff cts of stresse (residual and oper tional) on the constraint parameters are studied. It is shown that a two-parameter methodology provid effective charact ization of thre dimensional el stic – plastic crack tips constraint. © 2016 The Authors. Published by Elsevier B.V. Peer-review under espons bility of the Scientific Committee of ECF21. Keywords: constraint parameters; T-stress; T z -factor; Q-factor; residual stress 1. Introduction Residual stresses are present in most mechanical or thermal components due to the fabrication methodology, such as wel ing. They attract cons derable attention in engineering applications, because of their impact on part distortion, servic performance and the cos s ass ciated with failures (Gannon et al., 2010). Ther fore, it is necessary to understand the combined effect of mechanical lo ding and residual stresses on the fracture of structures i order to provi a more a curate structural integrity assessme t. The pre iction of crack initiation and propagatio requi es 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. © 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 © 2016 The Authors. Published by Elsevier B.V. Peer-review under responsibility of the Scientific Committee of ECF21. * Corresponding author. Tel.: +44-0161-306-2737; fax: +44-0161-306-2737. E-mail address: Abolfazl.Zahedi@manchester.ac.uk 2452-3216 © 2016 The Authors. Published by Elsevier B.V. Peer review under r sponsibility of the Scientific Committee of ECF21. * Corresponding author. Tel.: +44-0161-306-2737; fax: +44-0161-306-2737. E-mail ad ress: Ab lfazl.Zahedi@manchester.ac.uk

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.2016.06.100