PSI - Issue 12

ScienceDirect Available online at www.sciencedirect.com Available online at www.sciencedire t.com ienceDirect Structural Integrity Procedia 00 (2016) 000 – 000 Procedia Structu al Integrity 12 (2018) 5 7–52 Available online at www.sciencedirect.com ScienceDirect Structural Integrity Procedia 00 (2018) 000 – 000 Available online at .sciencedirect.co i ir ct 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. AIAS 2018 International Conference on Stress Analysis Modeling the effects of tolerances and assembly errors on the optical performances of parabolic collectors in a concentrating solar power system F. Cadini a* , M. Fossati a , M. Donati a , S. Cardamone a , M. Giglio a a Politecnico di Milano, Dipartimento di Meccanica,via La Masa 1, 20156 Milano, Italy The major problem related to the implementation of Concentrating Solar Power (CSP) systems is related to their Levelized Cost of Electricity (LCOE), which is still higher than that associated to other energy production methods, thus limiting their competitiveness. It is widely recognized that large cost savings can still be achieved by improving the collector and solar field designs. In this context, one important issue is that, currently, v ry detailed analyses of CSP components’ production tolerances and assembly/mounting err rs are performed i n order to guarantee the desired optical performances of a CSP plant. Unfortunately, these analyses require very large computational efforts, so that full design optimizations, implying many model runs, become almost impractical. Hence, the main objective of this work is that of developing new, lean methodologies, still relying on proper experimental knowledge, for supporting the CSP system optimal design at affordable computational expenses. The methodological approach stems from an extension of a semi-analytic model of literature for the calculation of the intercept factor, i.e., an important optical efficiency parameter. The proposed modifications explicitly account for the effects of the production tolerances and assembly/mounting errors by including simple, parameterized FEM calculations and geometric considerations. After properly casting the problem into a probabilistic framework, we exploit the simplicity and computational speed of the proposed model in order to perform a Sobol based global sensitivity analysis (GSA) of the CSP optical performances. From a purely engineering point of view, the results of this kind of analysis provide fundamental insights for supporting a decision-making process aimed at optimizing the CSP component production and the solar plant assembly/mounting at a full power production scale. © 2018 The Authors. Published by Elsevier B.V. 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 AIAS 2018 International Conference on Stress Analysis. Keywords: Solar energy; parabolic trough collector; optical efficiency; sensitivity analysis; optimization, cost minimization, genetic algorithms. 1. Introduction The Concentrating Solar Power (CSP) technology is a modern power generation strategy based on the use of properly designed mirrors capable of concentrating the sun’s rays on a focal point (or line), thus increasing the temperature of a the rmo vector fluid. In most of today’s CSP systems, this heat is used to produce steam, which is then used to drive conventional steam turbines cycle. Despite the sunrays properties have been known since the ancient time, the adoption of this technique for the energy production on a large scale is rather recent, more recent than photovoltaic (PV) technology, which is nowadays rather spread out, 2018 The uthors. Published by Els i . . This is an open access article under the CC B -N li ( tt ://creativecommons.org/licenses/by-nc-nd/3.0/) Peer-revie under responsibility f the Scientifi C AI 0 Int r atio l nfere ce Stress Analysis. I 2018 International onference on tress nalysis li t ff t f t l r l rr r t ti l rf r f r li ll t r i tr ti l r r t F. Cadini a* , M. ssati a , . ati a , . ar a e a , . i li a a Politecnico di ilano, Dipartimento di eccanica,via La asa 1, 20156 ilano, Italy bstract The major problem related to the implementation of Concentrating Solar Power (CSP) systems is related to their Levelized Cost of Electricity (LC E), hich is still higher than that associated to other energy production ethods, thus li iting their co petitiveness. It is idely recognized that large cost savings can still be achieved by i proving the collector and solar field designs. In this context, one i portant issue is that, currently, very detailed analyses of CSP co ponents’ production tolerances and asse bly/ ounting errors are perfor ed i n order to guarantee the desired optical perfor ances of a CSP plant. nfortunately, these analyses require very large co putational efforts, so that full design opti izations, i plying any odel runs, beco e al ost i practical. ence, the ain objective of this ork is that of developing ne , lean ethodologies, still relying on proper experi ental kno ledge, for supporting the CSP syste opti al design at affordable co putational expenses. The ethodological approach ste s fro an extension of a se i-analytic odel of literature for the calculation of the intercept factor, i.e., an i portant optical efficiency para eter. The proposed odifications explicitly account for the effects of the production tolerances and asse bly/ ounting errors by including si ple, para eterized FE calculations and geo etric considerations. fter properly casting the proble into a probabilistic fra ework, we exploit the simplicity and computational speed of the proposed model in order to perform a Sobol based global sensitivity analysis (GSA) of the CSP optical performances. From a purely engineering point of view, the results of this kind of analysis provide fundamental insights for supporting a decision-making process aimed at opti izing the CSP co ponent production and the solar plant assembly/mounting at a full power production scale. th rs. li l i r . . his is a en access article er t C - - lice se ( tt ://creativeco ons.org/licenses/by-nc-nd/3.0/) eer-re ie u der res si ilit f t e cie tific C ittee f I 2018 Int rnational onference on Stress nalysis. Keyw rds: Solar energy; parabolic trough collector; optical efficiency; sensitivity analysis; optimization, cost minimization, genetic algorithms. 1. Introduction The oncentrating Solar Po er ( SP) technology is a o ern po r generation strategy based on the use of properly designed irrors capable of concentrating the sun’s rays on a focal point (or line), thus increasing the te perature of a the r o vector fluid. In ost of today’s SP syste s, this heat is used to produce stea , hich is then used to drive conventional stea turbines cycle. espite the sunrays properties have been kno n since the ancient ti e, the adoption of this technique for the energy production on a large scale is rather recent, ore recent than photovoltaic (P ) technology, hich is no adays rather spread out, © 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. Tel.: +351 218419991. E-mail address: amd@tecnico.ulisboa.pt * Corresponding author. Tel.: +39-02-2399-6355. E-mail address: francesco.cadini@polimi.it * Corresponding author. Tel.: +39-02-2399-6355. E-mail address: francesco.cadini polimi.it

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. 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 AIAS 2018 International Conference on Stress Analysis. 10.1016/j.prostr.2018.11.067 2452-3216 © 2018 The Authors. Published by Elsevier B.V. This is an open access article under the CC BY-NC-ND lic ns (http://creativecommons.org/licenses/by-nc-nd/3.0/) Peer-review under responsibility of the Scienti ic Committee of AIAS 2018 International Conference on Stress Analysis. 2452-3216 © 2018 The Authors. Published by Elsevier B.V. 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 AIAS 2018 International Conference on Stress Analysis.