PSI - Issue 13

ScienceDirect Available online at www.sciencedirect.com Available online at ww.sciencedire t.com ienceDirect Structural Integrity Procedia 00 (2016) 000 – 000 Procedia Structu al Integrity 13 (2018) 571–577 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. © 2018 The Authors. Published by Elsevier B.V. Peer-review under responsibility of the ECF22 organizers. ECF22 - Loading and Environmental effects on Structural Integrity A local limit load model for J prediction via the reference stress method Yuebao Lei a * a EDF Energy Nuclear Generation Ltd., Barnett Way, Barnwood, Gloucester, GL4 3RS, UK Abstract A local limit load model is developed for shell/plate type components with surface cracks for determining the local limit load or local reference stress used in J prediction via the reference stress J scheme for defective components. The model is a plate which contains a rectangular surface crack circumscribing the real surface defect and has the same thickness as the component at the crack location. The model is remotely loaded by the primary stresses of the component at the crack location obtained from elastic uncracked-body stress analysis. The global limit load of this model is used as the local limit load of the defective component. The model is validated using 273 cases of 3-D finite element (FE) J results for semi-elliptical surface cracks in plates, cylinders and elbows. The results show that when this local limit load is used in the reference stress J prediction scheme, the predicted J values are reasonably accurate but conservative, compared with the FE J values. © 2018 The Authors. Published by Elsevier B.V. Peer-review under responsibility of the ECF22 organizers. Keywords: Structural integrity assessment, Reference stress J scheme, J-integral, Limit load, Local limit load 1. Introduction In the R6 procedure [R6 (2015)], the J-integral based failure assessment diagram (FAD) method is adopted for structural integrity assessment of defective components. For fracture assessment, this method is underpinned by the reference stress J estimation scheme [Ainsworth (1984)] which requires inputs of the limit load of the defective component and the stress intensity factor (SIF). It is found [e.g. Lei (2007)] that for simple geometries using the global limit load can lead to more accurate J predictions. However, for complex structures the global limit load may be, ECF22 - Loading and Environmental effects on Structural Integrity A local limit load model for J prediction via the reference stress method Yuebao Lei a * a EDF Energy Nuclear Generation Ltd., Barnett Way, Barnwood, Gloucester, GL4 3RS, UK Abstract A local limit load model is developed for shell/plate type components with surface cracks for determining the local limit load or local reference stress used in J prediction via the reference stress J scheme for defective components. The model is a plate which contains a re tangular surface crack circumscribing the real surface defect and has the same thick ss as t component at the crack l cation. The model is remotely loaded by the primary stresses of the component at the cr ck locat on btained from ela tic uncracked-body str ss analysis. The global limit load of this model is used as the local limit lo d of the defective comp nent. The model is validated using 273 cases of 3-D finite element (FE) J results for emi-elliptical surface cracks in plates, cyli ders and elbows. The results show that when this local limit load is used in the reference stress J prediction scheme, the predicted J values are reasonably accurate but conservative, compared with the FE J values. © 2018 The Authors. Published by Elsevier B.V. Peer-review under responsibility of the ECF22 organizers. Keywords: Structural integrity assessment, Reference stress J scheme, J-integral, Limit load, Local limit load 1. Introduction In the R6 procedure [R6 (2015)], the J-integra based failure assessment diagram (FAD) method is adopted for structural integrity assessment of defective components. For fracture assessment, this method is underpinned by the reference stress J estimation scheme [Ainsworth (1984)] which requires inputs of the limit load of the defective component and the stress intensity factor (SIF). It is found [e.g. Lei (2007)] that for simple geometries using the global limit load can lead to more accurate J predictions. However, for complex structures the global limit load may be, © 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.: +44-1452652285 E-mail address: yuebao.lei@edf-energy.com * Corresponding author. Tel.: +44-1452652285 E-mail ad ress: yuebao.lei@edf energy.com

* 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.2018.12.094