PSI - Issue 5

ScienceDirect Available online at www.sciencedirect.com Av ilable o line at ww.sciencedire t.com ScienceDirect Structural Integrity Procedia 00 (2016) 000 – 000 Procedia Struc ural Integrity 5 (2017) 1176–1183 Available online at www.sciencedirect.com ScienceDirect Structural Integrity Procedia 00 (2017) 000 – 000 il l li t . i i t. tr t r l I t rit r i ( )

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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. 2nd International Conference on Structural Integrity, ICSI 2017, 4-7 September 2017, Funchal, Madeira, Portugal Threshold selection for extreme strain extrapolation due to vehicles on bridges Xia Yang, Jing Zhang*, Wei-Xin Ren School of Civil Engineering, Hefei University of Technology, Anhui Province 230001, P. R. China In the design and condition assessment of brid es, the extreme vehi le load effects are necessary to be taken into consideration which may occur during the service period of bridges. In order t obt in an accurate extrapolation of the extreme value based on limited duration, threshold selection is a critical step in the peak-over-threshold method. Overly high threshold results in little information to be used and excessively low threshold leads to large bias in parameters estimation of generalized Pareto distribution. To investigate this issue, 417 days of strain data acquired from the long-term structural health monitoring system of Taiping Lake Bridge in China are employed in this paper. According to the tail distribution of the strain data induced by vehicle loads, four homothetic distributions are chosen as the parent distributions, from which lots of random samples are generated by the Monte Carlo method. For each parent distribution, the 100-yearly extreme values at different thresholds are estimated and compared with the theoretical value based on those samples. Then a simple and empirical threshold selection method is proposed, which can be an effective threshold selection tool for the extreme value estimation of vehicle load effect in future engineering practice. © 2017 The Authors. Published by Elsevier B.V. Peer-review under responsibility of the Scientific Committee of ICSI 2017. Keywords: Bridge health monitoring; extreme value esti ation; generalized Pareto distribution; peak-over-threshold; threshold selection Madeira, Port on bridges l f i il i i , f i i it f l , i i , . . i In the design and condition assessment of bridges, the extreme vehicle load effects are necessary to be taken into consideration i i t i i i . t t in an accurate extrapolation of the extreme value based on li it ti , t l l ti i iti l t i t t l t . l i t l lt i littl i ti t i l l t l l t l i i t ti ti li t i t i ti . i ti t t i i , t i t i t l t t t l lt it i t i i i i i l i t i . i t t t il i t i ti t t i t i i l l , t ti i t i ti t t i t i ti , i l t l t t t l t . t i t i ti , t l t l t i t t holds are estimated and compared with t t ti l l t l . i l i i l threshold selection method is proposed, which can be ti t l l ti t l t t l ti ti i l l t i t i i practice. © 2017 The Authors. Published by El vier B.V. Peer-review under responsibility of the Sci ti i itt . : ri lt it ri ; tr l tim ti ; r li r t i tri ti ; - r-t r l ; t r l l ti © 2017 The Authors. Published by Elsevier B.V. Peer-review und r responsibility of the Scientific Committee of ICSI 2017 Abstract

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© 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. Safety assessment of bridges plays an important role in bridge management, for which the load-carrying capacity of bridges and the associated uncertainties are needed to be evaluated accurately. A large volume of research work has t t l i i t, i t l i it i t i t t i ti t l t t l . l l t t i l i

* Corresponding author. Tel.: +86-18255198006. E-mail address: zhangj@hfut.edu.cn i t r. l.: - . - il : j f t. . rr

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.2017.07.030 * Corresponding author. Tel.: +351 218419991. E-mail address: amd@tecnico.ulisboa.pt 2452-3216 © 2017 The Authors. Published by Elsevier B.V. Peer-review under responsibility of the Scientific Committee of ICSI 2017. l i r . . i i ilit t i ti i itt . - t r . li