PSI - Issue 8

ScienceDirect Available online at www.sciencedirect.com Av ilable o line at ww.sciencedire t.com Sci ceDirect Structural Integrity Procedia 00 (2016) 000 – 000 Procedia Structu al Integrity 8 (2018) 39 –398 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. Copyright © 2018 The Authors. Published by Elsevier B.V. Peer-review under responsibility of the Scientific Committee of AIAS 2017 International Conference on Stress Analysis AIAS 2017 International Conference on Stress Analysis, AIAS 2017, 6-9 September 2017, Pisa, Italy Correction formula approach to evaluate fatigue damage induced by non-Gaussian stress state F. Cianetti a, *, M. Palmieri a , C. Braccesi a ,G. Morettini a a University of Perugia, Department of Engineering, via G. Duranti 93, 06125 Perugia, Italy Abstract In the present paper the authors define an original analytical expression of a corrective coefficient to evaluate fatigue damage induced by a non-Gaussian stress state affected by high Kurtosis (values higher than 5) and by zero Skewness. This approach starts from a previous activity in which the authors solve an analogous problem but for light non Gaussian stress states (Kurtosis value less than 5). The proposed procedure assumes to know the fatigue damage induced by Gaussian equivalent stress state time domain process. This characteristic allows the proposed procedure to be easily adopted inside the so-called Frequency Domain Fatigue Methods but in parallel with the statistical analysis of the system time domain response (Kurtosis and Skewness evaluation). Interesting considerations about its applicability will be proposed as concerns the non-Gaussianity an non Stationarity of the inputs when the system is a flexible component excited in its frequency range. © 2017 The Author . Published by Elsevier B.V. Peer-review und r responsibility of the Scientific Committee of AIAS 2017 Internat onal Conference o Stress Analysis. Keywords: R ndom Fatigue, Kurt sis, non-Gaussianity, Spectral ethods AIAS 2017 International Conference on Stress Analysis, AIAS 2017, 6-9 September 2017, Pisa, Italy Correction formula approach to evaluate fatigue damage indu ed by non-Gaussian stress state F. Cianetti a, *, M. Palmieri a , C. Braccesi a ,G. Morettini a a University of Perugia, Department of Engineering, via G. Duranti 93, 06125 Perugia, Italy Abstract In the present paper the authors define an original analytical expression of corrective coefficie t to evaluate fatigue damage induc d by a n n-Gaussian stress state affected by high Kurtosis (values higher than 5) and by zero Skew ess. This approach starts from a pre io s activity in which the authors solved an analogous problem but for light non Gaussian stress states (Kurtosis value less than 5). The proposed procedure assumes to know the fatigue amage induced by Gaussian equivalent stress state time d i process. This characteristic allows the propo ed procedure to be easily adopted inside the so-called Frequency Domain Fatigue M thods but in parallel with the statistical analysis of the system time domain response (Kurtosis and Sk wness evaluation). Interesting considerations about its applicability will be proposed as concerns the non-Gaussianity and non Stationarity of the inputs when the ystem is flexible component excit d in its f equency range. © 2017 The Authors. Publ shed by Elsevier B.V. Peer-review under responsibility of the Scientific C mmittee of AIAS 2017 Inter ational Conferenc on Stre s Analysis. Keywo ds: Random Fatigue, K rtosis, non-Gaus ianity, Spectral methods

1. Introduction

© 2016 The Authors. Published by Elsevier B.V. Peer-review under responsibility of the Scientific Committee of PCF 2016. 1. Introduction

Keywords: High Pressure Turbine Blade; Creep; Finite Element Method; 3D Model; Simulation. From several years, the fatigue damage is generally computed with a frequency domain approach. Even if the rainflow counting method [1] is considered as the most reliable in terms of results, it requires long computational time Fr m several years, the fatigue damage is generally computed with a frequency domain approach. Even if the rainflow counting method [1] is considered as the most reliable in terms of results, it requires long computational time

* Corresponding author. Tel.: +39 75 585 3728; fax: +39 75 585 3703. E-mail address: filippo.cianetti@unipg.it * Correspon ing author. Tel.: +39 75 585 3728; fax: +39 75 585 3703. E-mail address: filippo.cianetti@unipg.it

2452-3216 © 2017 The Authors. Published by Elsevier B.V. Peer-review under responsibility of the Scientific Committee of AIAS 2017 International Conference on Stress Analysis. 2452 3216 © 2017 Th Authors. Published by Elsevier B.V. Peer-review under responsibility of the Scientific Committee of AIAS 2017 International Conference on Stress Analysis.

* Corresponding author. Tel.: +351 218419991. E-mail address: amd@tecnico.ulisboa.pt

2452-3216 © 2016 The Authors. Published by Elsevier B.V. Peer-review under responsibility of the Scientific Committee of PCF 2016.

2452-3216 Copyright  2018 The Authors. Published by Elsevier B.V. Peer-review under responsibility of the Scientific Committee of AIAS 2017 International Conference on Stress Analysis 10.1016/j.prostr.2017.12.039