PSI- Issue 9

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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. © 2018 The Authors. Published by Elsevier B.V. Peer-review under responsibility of the Gruppo Italiano Frattura (IGF) ExCo. IGF Workshop “ Fracture and Structural Integrity ” The influence of metallurgical data on residual stresses in Computational Welding Romanin Luca a, *, Ferro Paolo a , Berto Filippo b a University of Padua, Stradella S. Nicola 3, Vicenza 36100, Italy b NTNU, Richard Birkelands vei 2b, Trondheim 7194, Norway Abstract Fusion welding processes are the primary joining techniques used in the fabrication of civil structures and mechanical engineering assemblies. The fusion of the parent and filler materials and the subsequent rapid cooling induce thermal and residual stresses within the component, leading to its distortion. Numerical codes used to simulate the welding process are continuously gaining interest for their potential to determine the optimum process parameters. However, the reliability of the results obtained by means of finite element analysis (FEA) is conditioned to the quality of metallurgical parameters. In particular, continuous cooling transformation phase diagrams are not always available in literature and, even when some empirical relations are used to estimate the phase transformation temperatures, the results obtained contain some inaccuracies. This work is aimed to study the influence of two main metallurgical parameters, i.e. the bainite start and martensite start transformation temperatures and the time constant for each cooling speed, on thermal residual stresses. In addition, the phase distribution has also been assessed due to its importance concerning the embrittlement of the weld. Phase distribution has been found to be very sensitive to metallurgical parameters. Errors in phase proportion evaluation go up to 100% and 20% for inpu rrors ( M start , B start ) the range of 50 °C and 20 °C, respectively; such uncertainties in transformation temperatures are plausible if empirical correlation to estimate metal urg cal data are used. On the ot er hand, residual stresses are lesse influenced by errors in metallurgical data, being the discrepancy for the mean stress less than 2% with an bsolute error of 20 °C for M start . 20 The Authors. ublished by lsevier .V. eer-revie under responsibility of the Gruppo Italiano Frattura (I ) ExCo. Keywords: Computational Welding Mechanics; Uncertanties, Metallurgical Model; 1. Introduction Fusion welding represents one of the main joining methods used in steel construction industry. In fact, it is less cost and time expensive than other joining techniques. However, residual stresses and distortions are introduced in the workpiece in addition to those coming from cutting or cold forming. To keep deformations under control, experience plays an important role in this field. Nowadays, computational welding mechanics is proving itself as a viable method to simulate the chosen welding process. Designers are particularly interested in residual stresses and deformations assessment; in this way they can study the best welding process and assembly procedure. In order to obtain correct dimensional tolerances in mechanical engineering assemblies, it’s IGF Workshop “ Fracture and Structural Integrity ” The influence of metallurgical data on residual stresses in Computational Welding Romanin Luca a, *, Ferro Paolo a , Berto Filippo b a University of Padua, Stradella S. Nicola 3, Vicenza 36100, Italy b NTNU, Richard Birkelands vei 2b, Trondheim 7194, Norway Abstract Fusion welding processes are the pri ary joining techniques used in the fabrication of civil structures and mechanical engineering assemblies. The fusion of the parent and filler materials and the subsequent rapid cooling induce thermal and residual stresses within the component, leading to its distortion. Numerical codes used to simulate the welding process are continuously gaining interest for their potential to determine the optimum process parameters. However, the reliability of the results obtained by means of finite element analysis (FEA) is conditioned to the quality of metallurgical parameters. In particular, continuous cooling transformation phase diagrams are not always available in literature and, even when some empirical relations are used to estimate the phase transformation temperatures, the results obtained contain some inaccuracies. This work is aimed to study the influence of two main metallurgical parameters, i.e. the bainite start and martensite start transformation temperatures and the time constant for each cooling speed, on thermal residual stresses. In addition, the phase distribution has also been assessed due to its importance concerning the embrittlement of the weld. Phase distribution has been found to be very sensitive to metallurgical parameters. Errors in phase proportion evaluation go up to 100% and 20% for input errors ( M start , B start ) in the range of 50 °C and 20 °C, respectively; such uncertainties in transformation temperatures are plausible if empirical correlation to estimate metallurgical data are used. On the other hand, residual stresses are lesser influenced by errors in metallurgical data, being the discrepancy for the mean stress less than 2% with an absolute error of 20 °C for M start . © 2018 The Auth s. Publ shed by Elsevier B.V. Peer-review under responsibility of the Gruppo Italiano Frattura (IGF) ExCo. Keywords: Computational Welding Mechanics; Uncertanties, Metallurgical Model; 1. Introduction Fusion welding represents one of the main joining methods used in steel construction industry. In fact, it is less cost and time expensive than other joining techniques. However, residual stresses and distortions are introduced in the workpiece in addition to those coming from cutting or cold forming. To keep deformations under control, experience plays an important role in this field. Nowadays, computational welding mechanics is proving itself as a viable method to simulate the chosen welding process. Designers are particularly interested in residual stresses and deformations assessment; in this way they can study the best welding process and assembly procedure. In order to obtain correct dimensional tolerances in mechanical engineering assemblies, it’s IGF Workshop “ Fracture and Structural Integrity ” The influence f metallurgical data on residu l stresses in C Welding Romanin Luca a, *, Ferro Paolo a , Berto Filippo b a U iversity of Padua, Stradella S. Nicola 3, Vicenza 36100, Italy b NTNU, Rich rd Birkelands vei 2b, Trondheim 7194, Norway Abstract Fus on weldi g proce ses are the p im ry j ining techniqu used in t e fabricatio of civil tructures and mechan The fusion of the par and filler materials and the subsequent r pid cooling induce ther al a d residual str leading to its distortion. Nume ical codes used to simulate the welding process re continu usly gai ing interest fo the optimum process parameters. However, the reliability of the results obtained by means of finite elem nt anal sis (FEA) is conditioned to parameters. In particular, continuous cooli g transformat on phase diagrams are not al ays available in liter mpirical relations are used to estimate the pha e transformation temp ratures, the results obtained contain some in This work is imed o study the influence of two main met llurgical parameters, i.e. the bainite start and ma temperatures and the time constant for each cooling speed, on therm l residual stresse . In addition, the phas ass ssed due to its importance concerning the embrittlement of the weld. Phase di tr buti n has been found to b very sensitive to metallu gical p rameters. Errors in phase proportion ev 20% for input errors ( M start , B start ) in th range of 50 °C and 20 °C, respectively; such uncertainties in tran plausible if empiric l co relation to estimat metallurgical data are used. On the other hand, r sidual stresses are l met llurgical data, b ing the discrepancy for the mean stress less than 2% with an absolute rror of 20 °C for M start . © 2018 The Aut ors. Published by Elsevier B.V. Peer-review under responsibility of the Gruppo Italiano Frattura (IGF) ExCo. Keywords: Comput tional Welding Mechanics; Uncertanties, Metallurgical Model; 1. Introduction Fus on elding repre ents one of the main jo ning methods used in steel construction industry. In fact, i expensiv than other joining techniques. H wev r, resi al stresses and distort ons are i tr duced in the those coming from cutting or cold for ing. To keep d formations under control, exper nce plays an im Nowadays, computational weld ng mechanics is proving itself a a viable meth d to simulate the chosen Designers are particularly interested in r idual stresses and deform tions assessment; in this way they c process and assembly procedure. In order to obtain orre t dime sional tolerances in mechanical engine © 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.

* Corresponding author. Tel.: +351 218419991. E-mail address: amd@tecnico.ulisboa.pt * Corresponding author. E-mail address: luca.r manin@phd.unipd.it * Corresponding author. E-mail address: luca.romanin@phd.unipd.it

* Corresponding author. E-mail address: luca.romanin@phd.unipd.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. Peer-review under responsibility of the Gruppo Italiano Frattura (IGF) ExCo. 10.1016/j.prostr.2018.06.011 2452-3216 © 2018 The Authors. Published by Elsevier B.V. Peer-review under responsibility of the Gruppo Italiano Frattura (IGF) ExCo. 2452-3216 © 2018 The Authors. Published by Elsevier B.V. Peer-revi w under respon ibility of the Gruppo Italiano Frattura (IGF) ExCo.

2452-3216 © 2018 The Authors. Published by Elsevier B.V. Peer-review under responsibility of the Gruppo Italiano Frattura (IGF) ExCo.