PSI - Issue 14

ScienceDirect Available online at www.sciencedirect.com Av ilable online at www.sciencedire t.com ScienceDirect Structural Integrity Procedia 00 (2016) 000 – 000 Procedia Structu al Integrity 14 (2019) 549–555 Available online at www.sciencedirect.com ScienceDirect Structural Integrity Procedia 00 (2018) 000–000 Available online at www.sciencedirect.com Sci c ir ct 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. © 2019 The Authors. Published by Elsevier B.V. This is an open access article under the CC BY-NC-ND license (https://creativecommons.org/licenses/by-nc-nd/4.0/) Selectio and peer-review under responsibility of Peer-review under responsibility of t e SICE 2018 organizers. 2nd International Conference on Structural Integrity and Exhibition 2018 Study the Effect of Anisotropy of Elastic-Plastic Properties on Residual Stress Devel pment in Autofrettage of Thick Cylinder Ritu .J. Singh*, Ramesh Kumar, J. Mishra, V. Balasubramaniyam Atomic Energy Regulatory Board, Niyamak Bhavan, Anushaktinagar, Mumbai 400094, India Abstract Thick-walled cylinders subjected to high internal pressure and/or elevated temperatures are widely used in the aircraft, defence, nuclear and chemical industries especially for military applications e.g. the gun barrel in a ballistic event. In the absence of residual stresses, cracks usually form at the bore where the hoop stress developed by the working pressure is highest. To prevent such failure and to increase the pressure-carrying capacity of the pressure vessel, autofrettage process is used. During autofrettage a plastic region within the thick wall of the pressure vessel is produced by loading the pressure vessel in the plastic domain. Upon unloading, a residual compressive hoop stress is established within the plastic zone. This residual compressive stress counters the tensile hoop stress introduced due to service loading, thereby reducing the overall tensile hoop stress at inner surface. Therefore, autofrettage is used to introduce advantageous favourable compressive residual hoop stress inside wall of a cylinder and result in an increase in the fatigue lifetime of the component. Several researchers have studied the autofrettaged cylinders, both analytically and FE simulation. In this paper, effect of orthotropic anisotropy in the material properties will be studied on the stress field generated in the autofrettaged cylinder. Anisotropy in the material properties may result due to manufacturing processes like extrusion or pilgering. Plastic deformation leads to the development of preferred orientation of grains in the components due to slip occurring only in preferred slip planes in a crystal especially in a HCP material like Zr 2.5%Nb. In this paper, a thick cylinder made from Zr 2.5% Nb is loaded till elasto plastic interface is achieved and then unloaded to study effect of anisotropy on the development of residual stresses. Two material models are considered in the analysis i.e. isotropic and anisotropic pl stic behaviour. The effect of anisotropy on the residual stress is investigated. © 8 e Aut ors. ublished by Elsevier . . This is a open access article under the CC BY- -N license (https://creativecom ons.org/licenses/by-nc-nd/4.0/) Selectio and peer-revie under responsibility of eer-revie under responsibility of t e ICE 2018 organizers. Keywords: anisotropy;residual stress;autofrettage;thick cylinder 1. Introduction Thick-walled cylinders subjected to high internal pressure and/or elevated temperatures are widely used in the aircraft, defense, nuclear and chemical industries especially for military applications e.g. the gun barrel in a ballistic event. In the absence of residual stresses, cracks usually form at the bore where the hoop stress developed by the working pressure is highest. To prevent such failure and to increase the pressure-carrying capacity of the pressure vessel, autofrettage process is used. Autofrettage is a process to obtain favorable initial stress pattern in the cylinder. A sufficiently high internal pressure is applied in the cylinder so as to produce plastic 2nd International onference on Structural Integrity and Exhibition 2018 t t e ffect f is tr f lastic- lastic r erties esi al tress e elo e t i t fretta e f ic li er itu .J. Singh*, a esh u ar, J. ishra, . alasubra aniya Atomic Energy Regulatory Board, Niyamak Bhavan, Anushaktinagar, Mumbai 400094, India Abstract Thick-walled cylinders subjected to high internal pressure and/or elevated temperatures are widely used in the aircraft, defence, nuclear and chemical industries especially for military applications e.g. the gun barrel in a ballistic event. In the absence of residual stresses, cracks usually form at the bore where the hoop stress developed by the working pressure is highest. To prevent such failure and to increase the pressure-carrying capacity of the pressure vessel, autofrettage proc ss is used. During autofrettage a plastic region within the thick wall of the pressure vessel is produced by loading the pressure vessel in the plastic domain. Upon unloadin , a residual compressive hoop stress is established within the plastic zone. This residual compressive stress counters the tensile hoop stress introduced due to service loading, thereby reducing the overall tensile hoop stress at inner surface. Therefore, autofrettage is used to introduce advantageous favourable compressive residual hoop stress inside wall of a cylinder and result in an increase in the fatigue lifetime of the component. Several researchers have studied the autofrettaged cylinders, both analytically and FE simulation. In this paper, effect of orthotropic anisotropy in the material properties will be studied on the stress field generated in the autofrettaged cylinder. Anisotropy in the material properties may result due to manufacturing processes like extrusion or pilgering. Plastic deformation leads to the development of preferred orientation of grains in the components due to slip occurring only in preferred slip planes in a crystal especially in a HCP material like Zr 2.5%Nb. In this paper, a thick cylinder made from Zr 2.5% Nb is loaded till elasto plastic interface is achieved and then unloaded to study effect of anisotropy on the development of residual stresses. Two material models are considered in the analysis i.e. isotropic and anisotropic plastic behaviour. The effect of anisotropy on the residual stress is investigated. 8 A t rs. lished by Elsevier . . is is rti l r t - -N license (htt ://creativecom ons.org/licenses/by-nc-nd/4.0/) election and peer-revie under responsibility of eer-revie under responsibility of the ICE 2018 organizers. Keywords: anisotropy;residual stress;autofrettag ;thick cylinder 1. Int oduction Thick-walled cylinders subjected to high internal pressure and/or elevated temperatures are widely used in the aircraft, defense, nuclear and chemical industries especially for military applications e.g. the gun barrel in a ballistic event. In the absence of residual stresses, cracks usually form at the bore where the hoop stress developed by the working pressure is highest. To prevent such failure and to increase the pressure-carrying capacity of the pressure vessel, autofrettage process is used. Autofrettage is a process to obtain favorable initial stress pattern in the cylinder. A sufficiently high internal pressure is applied in the cylinder so as to produce plastic © 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 * Corresponding author. Tel.: +91-22-25990468; fax: +91-22-25990499. E-mail address: ritusingh@a rb.gov.in * Corresponding author. Tel.: +91-22-25990468; fax: +91-22-25990499. E-mail address: ritusingh@aerb.gov.in

2452-3216 © 2016 The Authors. Published by Elsevier B.V. Peer-review under responsibility of the Scientific Committee of PCF 2016. 2452-3216  2019 The Authors. Published by Elsevier B.V. This is an open access article under the CC BY-NC-ND license (https://creativecommons.org/licenses/by-nc-nd/4.0/) Selection and peer-review under responsibility of Peer-review under responsibility of the SICE 2018 organizers. 10.1016/j.prostr.2019.05.067 2452-3216 © 2018 The Authors. Published by Elsevier B.V. This is an open access article under the CC BY-NC-ND license (https://creativecommons.org/licenses/by-nc-nd/4.0/) Selection and peer-review under responsibility of Peer-review under responsibility of the SICE 2018 organizers. 2452-3216 © 2018 The Authors. Published by Elsevier B.V. This is an open access article under the CC BY-NC-ND license (https://creativecommons.org/licenses/by-nc-nd/4.0/) Selection and peer-review under responsibility of Peer-review under responsibility of the SICE 2018 organizers.