PSI - Issue 5

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 Struc ural Integrity 5 (2017) 1229–1236 Available online at www.sciencedirect.com ScienceDirect Structural Integrity Procedia 00 (2017) 000 – 000 Available online at www.sciencedirect.com ScienceDirect Structural Integrity Procedia 00 (2017) 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. Comparison of Equivalent Stress Methods with Critical Plane Approaches for Multiaxial High Cycle Fatigue Assessment Zafer Engin a,b , Demirkan Coker a, * a Dept. of Aerospace Engineering, Middle East Technical University, Ankara, Turkey b Helicopter Group,Turkish Aerospace Industry, Ankara, Turkey Several equivalent stress methods and more advanced critical plane criteria are compared in terms of their performance in fa igue life estim tions under uniaxial and biaxial load ng in which the effect of ph e is investigated. For this purpose a MATLAB code is written which transforms the multiaxial cyclic stress state into a uniaxial cyclic stress to use with the equivalent stress based methods. For critical plane approaches the program searches a damage parameter on all material planes. The maximum damage parameter is then compared with a material allowable obtained from uniaxial fatigue tests for life estimation. In addition, various methods for calibration of the material coefficient k and prominent stress history enclosure m thods to calculate the shear stress amplitude a e also studied for d termining their ffect on th perform nce of critical plane pproaches. © 2017 The Authors. Published by Elsevier B.V. Peer-review under responsibility of the Scientific Committee of ICSI 2017. Keywords: multiaxial fatigue; high cycle fatigue; equivalent stress; critical plane; non-proportional loading; shear stress amplitude 2nd International Conference on Structural Integrity, ICSI 2017, 4-7 September 2017, Funchal, Madeira, Portugal Comparison of Equiv lent Stress Methods with Critical Plane Approaches for Multiaxial High Cycle Fatigue Assessment Zafer Engin a,b , Demirkan Coker a, * a Dept. of Aerospace Engineering, Middl East Technical University, Ankara, Turkey b Helicopter Group,Turkish Aerospace Industry, Ankara, Turkey Abstract Several quivalent stress eth ds and more advanced critical plane crit ria are compared in terms of their performance in fatigue life estimations under uniaxial d biaxial loadings in whi h the ffect of phase is investigated. For this purpose a MATLAB code is written which transforms the multiaxial cy lic stress state into uniaxial cyclic stress to use with the quivale t stress based etho s. For critical plane approaches the program searches damag par m ter n all material planes. The maximu damage parameter is then compared with a material allowable obtained from uniaxial fatigue tests for life estimation. In addition, various methods for calibration of the material c efficient k and prominent stress hist ry e losure methods to calculate the shear stress amplitude are also studied for determi ing their effect on the perf rmance of cr t cal plane approaches. © 2017 The Authors. Publ shed by Elsevier B.V. Peer-review und r responsibility of the Scientific Committee of ICSI 2017. Keywords: multiaxial fatigue; high cycle fatigue; equivalent stress; critical plane; non-proportional loading; shear stress amplitude © 2017 The Authors. Published by Elsevier B.V. Peer-review under responsibility of the Scientific Committee of ICSI 2017 © 2016 The Authors. Published by Elsevier B.V. Peer-review under responsibility of the Scientific Committee of PCF 2016. Many critical engineering parts designed with safe life methodology such as rotor blades, pressure vessels, railroad wheels, crankshafts and bolted joints experience cyclic loading that leads to biaxial or triaxial stress states. Fatigue Many critical engineering parts designed with safe life methodology such as rotor blades, pressure vessels, railroad wheels, crankshafts and bolt d joints xperience cyclic loading that leads to biaxial or triaxial stress states. Fatigue Keywords: High Pressure Turbine Blade; Creep; Finite Element Method; 3D Model; Simulation. 2nd International Conference on Structural Integrity, ICSI 2017, 4-7 September 2017, Funchal, Madeira, Portugal Abstract 1. Introduction 1. Introduction

* Corresponding author. Tel.: +903122104253. E-mail address: coker@metu.edu.tr * Correspon ing autho . Tel.: +903122104253. E-mail address: coker@metu.edu.tr

2452-3216 © 2016 The Authors. Published by Elsevier B.V. Peer-review under responsibility of the Scientific Committee of PCF 2016. 2452-3216  2017 The Authors. Published by Elsevier B.V. Peer-review under responsibility of the Scientific Committee of ICSI 2017 10.1016/j.prostr.2017.07.049 * Corresponding author. Tel.: +351 218419991. E-mail address: amd@tecnico.ulisboa.pt 2452 3216 © 2017 Th Authors. Published by Elsevier B.V. Peer-review under responsibility of the Scientific Committee of ICSI 2017. 2452-3216 © 2017 The Authors. Published by Elsevier B.V. Peer-review under responsibility of the Scientific Committee of ICSI 2017.