PSI - Issue 10

ScienceDirect Available online at www.sciencedirect.com Av ilable o line at ww.sciencedire t.com cienceDirect Structural Integrity Procedia 00 (2016) 000 – 000 Procedi Structural Integrity 1 8 11–17 Available online at www.sciencedirect.com ScienceDirect Structural Integrity Procedia 00 (2018) 000 – 000 il l li t . i ir t. tr t r l I t rit r i ( )

www.elsevier.com/locate/procedia . ls i r. /l t / 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. © 2018 The Authors. Published by Elsevier Ltd. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/3.0/) Peer-review under responsibility of the scientific committee of the 1st International Conference of the Greek Society of Experimental Mechanics of Materials. 1 st International Conference of the Greek Society of Experimental Mechanics of Materials Acoustic emission monitoring of marble specimens under uniaxial compression. Precursor phenomena in the near-failure phase D. Triantis* Laboratory of Electronic Devices & Materials, University of West Attica, Greece Abstract In the present study Acoustic Emission (AE) indices are used to characterize the damage process in marble rock specimen that is subjected to axial compressive stress. The I b -value which depends on the amplitude distribution of the AE hits, shows a consistent trend of decreasing from the level of 70% of the ultimate compressive strength. A steep decrease is observed when the stress exceeds the 95% of the ultimate strength reaching a value near 1, a fact that can be considered as a warning of the coming event of fracture. Additionally, the average frequency of the AE hits shows a severe shift to lower values by about 200 kHz when the dominant failure mechanism is related to shear type of failure. Similarly, RA which is defined as the ratio of the waveform Rise Time over the Amplitude in μs/V , shows strong peaks at the moments near the fracture, indicating shear action. © 2018 The Authors. Published by Els vier Ltd. This is an open access article under the CC BY-NC-ND license (http://creativec mmons.org/licenses/by-nc- d/3.0/). Peer-revi w under responsibility of the scientific committe of the 1 st International Conference of the Greek Society of Experimental Mechanics of Materials Keywords: Acoustic Emission; marble; I b -value; RA and AF values; crack classification 1. Introduction In the literature there are several recordings and studies of the Acoustic Emissions (AE) that are attributed to mechanical damages caused by microcracking in rocks (L ckner (1993); Shiotani et al. (2001); Yoshikawa and Mogi (1989)). When a material is subjected to external mechanical loading, the elastic mechanical energy is released in the form of Acoustic Emissions. Τ he change of the stress field insi the m terial which is related to the deformation 1 st t ti l t i t i t l i t i l . r t r f l tr i i s t ri ls, i rsit f st tti , r t t I t r t t ti i i ( ) i i r t r t ri t r i r l r i that i j t t i l r i tr . I b - l i t lit i tri ti f t it , i t t tr f r i fr t l l f f t lti t r i tr t . t r i r t tr t f t lti t tr t r i l r , f t t t i r r i f t i t f fr t r . iti ll , t r fr f t it r ift t l r l t t i t f il r i i r l t t r t f f il r . i il rl , i i fi t r ti f t f r i i r t lit i / , tr t t t r t fr t r , i i ti r ti . t rs. lis ls i r Ltd. is is ss rti l r t -NC-ND license ( tt :// r ti o s. r /li s s/ - - / . /). r-r ie r responsi ility of th s i ntific committee f th 1 st I t r ti l f r f t r i t f ri t l nics of Materi ls r s: sti issi ; r l ; I b - l ; l s; r l ssifi ti 1. Introduction I t lit r t r t r r r l r r i t i f t ti i i ( ) t t r ttri t t i l i r r i i r ( r ( ); i t i t l. ( ); i i ( )). t ri l i j t t t r l i l l i , t l ti i l r i r l i f t tr fi l i i t at ri l i i r l t t t f r ti © 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. t f r f ti i i .

* Tel.: +30 210 5385357 E-mail address : triantis@teiath.gr Received: March 25, 2018; Received in revised form: June 26, 2018; Accepted: July 04, 2018 l.: - il r ss : tri tis t i t . r i i r is f r : J , ; t : J l , i : r , ;

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 Ltd. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/3.0/) Peer-review under responsibility of the scientific committee of the 1st International Conference of the Greek Society of Experimental Mechanics of Materials. 10.1016/j.prostr.2018.09.003 2452- 3216 © 2018 The Authors. Published by Elsevier Ltd. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/3.0/). Peer-review under responsibility of the scientific committee of the 1 st International Conference of the Greek Society of Experimental Mechanics of Materials - t r . li l i r t . is is ss rti l r t - - li s ( tt :// r ti s. r /li s s/ - - / . /). r-r i u r r s si ilit f t s i tifi itt e f t st I t r ti l f r f t r i t f ri t l i s f t ri ls * Corresponding author. Tel.: +351 218419991. E-mail address: amd@tecnico.ulisboa.pt