PSI - Issue 13

ScienceDirect Available online at www.sciencedirect.com Av ilable o line at www.sciencedire t.com cienceDirect Structural Integrity Procedia 00 (2016) 000 – 000 Procedia Structu al Integrity 13 (2018) 469–474 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 Stress intensity factor for multiple cracks on curved panels Gordana Kastratović a *, Mustafa Aldarwish b , Aleksandar Grbović b , Nenad Vidanović a Khalid Eldwaib b a Faculty of Transport and Traffic Engineering, University of Belgrade, Vojvode Stepe 305 11000 Belgrade, Serbia b Faculty of Mechanical Engineering, University of Belgrade, Kraljice Marije 16, 11120 Belgrade 35, Serbia The aim of this aper is to explore nd to demonstrate the capacity, perf rmances and ifficulties of stress intensity factors (SIFs) calculations in a case of multiple cracks on curved panels analyzed by means of different computational methods. So-called bulging effect, which is occurring in cracked curved panels, increases the effective stress-intensity factor, making the SIFs assessment in case of multiple cracks more challenging. Here, the stress intensity factors are considered by using two different computational methods: extended finite element method (XFEM) and the approximate method based on superposition, which has been adjusted for curved panel application. The SIFs determination was carried out for aircraft fuselage model: unstiffened panel with three cracked fastener holes, for four different curvature diameters, subjected to uniform internal pressurization. The comparison of the results showed that conducted analyses delivered the data which can be useful in evaluation of crack-growth rate, residual strength and fatigue life of curved aircraft structures with multi-site damage. © 2018 The Authors. Published by Elsevier B.V. Peer-review und r responsibility of the ECF22 organizers. Keywords: Multi-site dam ge; Stress intensity f ctor; Extended inite Elem nt Method; curved panels; 1. Introduction Over the recent years, problem of extended exploitation of aging aircraft structures is becoming more pressing, because of their diminishing structural integrity. This diminishing is largely caused by multiple site damage (MSD), which often occurs in longitudinal and circumferential riveted lap joints, starting when the fuselage pressure cycling fatigue loads lead to crack initiation and propagation at multiple rivet locations. Those multiple cracks may interact © 2018 The Authors. Published by Elsevier B.V. Peer-review under responsibility of the ECF22 organizers. ECF22 - Loading and Environmental effects on Structural Integrity Stress intensity factor for multiple cracks on curved panels Gordana Kastratović a *, Mustafa Aldarwish b , Aleksandar Grbović b , Nenad Vidanović a Khalid Eldwaib b a Faculty of Transport and Traffic Engineering, University of Belgrade, Vojvode Stepe 305 11000 Belgrade, Serbia b Faculty of Mechanical Engineering, University of Belgrad , Kr ljice Marij 16, 11120 Belgrad 35, Serbia Abstract The aim of this paper is to explore and to demonstrate the capacity, performances and difficulties of stress intensity factors (SIFs) calculati ns in a cas of multiple cracks on curved panels analyzed by mean of dif erent computational methods. So-called bulging effect, which is occurring in cracked curved panels, increases the effective str ss-intensity factor, making the SIFs assessment in case of multiple cracks more challenging. H re, the stres int nsity factors are considered by using two different computational meth ds: extended finite element method (XFEM) and the approximate method based on superposition, which has been adjusted for curved panel application. The SIFs determination was c rried out for aircraft fu lage model: unstiffened panel with three cracked fastener holes, for four different curvature diameters, subjected to uniform internal pressurization. The comparison of th results showed that conducted analyses deliv red th data which can be useful in evaluation of crack-growth rate, residual strength and fatigue life of curved aircr ft tructures with multi-site damage. © 2018 The Authors. Published by Elsevier B.V. Peer-review under responsibility of th ECF22 organiz rs. Keywords: Multi-site damage; Stres intensity factor; Extended Finite Element Method; urved panels; 1. Introduction Over the recent years, problem of extended exploitation of aging aircraft structures is becoming more pressing, because of th ir diminishing structural integrity. This diminishing is largely caused by multiple site damage (MSD), which often occurs in longitudinal and circumferential riveted lap joints, starting when the fuselage pressur cycling fatigue loads lead to crack initiation and propagation at multiple rivet locations. Those multiple cracks may interact © 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. E-mail address: g.kastratovic@sf.bg.ac.rs * Corresponding author. E-mail ad ress: g.kastratovic@sf.bg.ac.rs

* 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.2018.12.078