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 Structu al Integrity 13 (2018) 361–366 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. © 2018 The Authors. Published by Elsevier B.V. Peer-review under responsibility of the ECF22 organizers. ECF22 - Loading and Environmental effects on Structural Integrity Flaw interaction under bending, residual stress and thermal shock loading H. E. Coules* University of Bristol, Bristol, BS9 1TR, United Kingdom Abstract Crack-like surface flaws in pipes, pressure vessels and other structural components sometimes occur near to one another. When this happens, it is often necessary to take the mutual interaction of the flaws into account when performing fracture-mechanics-based fitness-for-service assessment. Integrity assessment procedures including ASME BPVC Section XI, BS 7910 and R6 include interaction criteria which are used during flaw characterisation to ensure that interaction is accounted for conservatively. This paper considers the interaction which occurs when flaws are loaded by a non-uniform through-wall distribution of stress, as may arise due to bending, thermal shock or welding/cladding residual stresses. Using parametric finite element analysis of a large number of crack pairs subjected to different distributions of stress, it is shown that the degree of flaw interaction can be enhanced under non-uniform loading. Therefore, care should be taken when performing integrity assessment using interaction criteria based on uniform tension loading only. © 2018 The Authors. Published by Elsevier B.V. Peer-review under responsibility of the ECF22 organizers. Keywords: fracture; flaw interaction; structural integrity assessment; weight function; finite element analysis. 1. Introduction 1.1. Flaw interaction When multiple crack-like flaws occur close to each other in a structure, the stress fields around them can interact. This interaction modifies the stress concentration which occurs at the tip of each crack, changing the strain energy release rate. If the i nteraction is significant then it can affect each crack’s proximity to fracture initiation. Therefore, the interaction between two cracks may cause the flawed component to fail under less severe loads than if they did ECF22 - Loading and Environmental effects on Structural Integrity Flaw interaction under bending, residual stress and thermal shock loading H. E. Coules* University of Bristol, Bristol, BS9 1TR, United Kingdom Abstract Crack-like surface flaws in pipes, pressure vessels and other structural components sometimes occur near to one another. When this happens, it is oft n necessary to take the mutual interaction of the flaws into account when performing fracture-mechanics-based fitness-for-service assessment. Integrity assessment procedures including ASME BPVC Section XI, BS 7910 and R6 include interacti n criteria which are used du ing flaw characte isation to ens re that int action is accounted for conservatively. This paper considers the interaction which occurs when flaws are loaded by a non-uniform through-wall distribution of stress, s ma arise due to be ding, thermal shock or welding/cladding residu l stress s. Using paramet ic finite element analysis f a larg number of crack pairs subjected to different dist ibutio s of stress, it i shown that the degree of flaw interaction ca be enhanced under on-uniform loading. Therefore, care shoul be taken when perform ng integrity ass ssment using interaction criteria based on uniform te sio l ading only © 2018 The Authors. Published by Elsevier B.V. Peer-review under respons bility of the ECF22 organizers. Keywords: fracture; flaw interaction; structural integrity assessment; weight function; finite element analysis. 1. Introduction 1.1. Flaw interaction When multiple crack-like flaws occur close to each other in a structure, the stress fields around them can interact. This interaction modifies the stress oncentration which occurs at the tip of each crack, changing the strain energy release rate. If the i nteraction is significant then it can affe t each crack’s proximity to fracture i itiation. Therefore, the interaction between tw cracks may cause the flawed component to fail under less severe loads than if they did © 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.: +44 (0)117 3315946. E-mail address: harry.coules@bristol.ac.uk * Corresponding author. Tel.: +44 (0)117 3315946. E-mail ad ress: harry coules@bristol.ac.uk

* 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.2018.12.060