PSI- Issue 9

ScienceDirect

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 P o edi Structural Integr ty 9 (2018) 64–70 Available online at www.sciencedirect.com ScienceDirect Structural Integrity Procedia 00 (2018) 000–000 Structural Integrity Procedia 00 (2018) 000–000

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www.elsevier.com/locate/procedia IGF Workshop “Fracture and Structural Integrity” Experimental and numerical analysis of TIG-dressing applied to a steel weldment P. Ferr a* , F. Berto b , . Bonollo a , R. Montanari c * IGF Workshop “Fracture and Structural Integrity” Experimental and numerical analysis of TIG-dressing applied to a steel weldment P. Ferro a* , F. Berto b , F. Bonollo a , R. Montanari c * 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-revi w und r responsibility of the Gruppo Italiano Fra tura (IGF) ExCo. a Department of Engineering and Management, University of Padova, Stradella San Nicola 3, 36100 Vicenza (Italy) b NTNU, Department of Engineering Design and Materials, Richard Birkelands vei 2b, 7491, Trondheim (Norway) c Department of Industrial Engineering, University of Rome Tor Vergata, Via del Politecnico 1, 00133, Rome (Italy) Abstract Fatigue strength of welded joints is controlled above all by notch defects such as weld toe and weld root that act as stress concentrators. This is the reason why over the last years different post-weld fatigue improvement techniques have been developed with the main propose of reducing geometrical discontinuities. Among these, TIG-dressing is the most used because of its simplicity and effectiveness in lowering the residual stress concentration. By this process the weld toe is re-melted to provide a smoother transition between the plate and the weld crown and to beneficially modify the residual stress redistribution. However, because of the intrinsic difficulty to numerically simulate the TIG-dressing process due to the high coupling between fluid and mechanical analysis, the effects of a weld toe remelting in terms of residual stress redistribution is hardly quantified in literature. The present paper is aimed to analyse the influence of TIG-dressing process on metallurgical and mechanical properties of a steel T-joint. Finally, a numerical model, recently published in literature, was used to quantified the residual stress redistribution. © 2018 The Authors. Published by Elsevier B.V. Peer-review under responsibility of the Gruppo Italiano Frattura (IGF) ExCo. Keywords: Welding; TIG-dressing; Modeling; Numerical simulation; Residual stress, Phase transformation a Department of Engineering and Management, University of Padova, Stradella San Nicola 3, 36100 Vicenza (Italy) b NTNU, Department of Engineering Design and Materials, Richard Birkelands vei 2b, 7491, Trondheim (Norway) c Department of Industrial Engineering, University of Rome Tor Vergata, Via del Politecnico 1, 00133, Rome (Italy) Abstract Fatigue strength of welded joints is controlled above all by notch defects such as weld toe and weld root that act as stress concentrators. This is the reason why over the last years different post-weld fatigue improvement techniques have been developed with the main propose of reducing geometrical discontinuities. Among these, TIG-dressing is the most used because of its simplicity and effectiveness in lowering the residual stress concentration. By this process the weld toe is re-melted to provide a smoother transition between the plate and the weld crown and to beneficially modify the residual stress redistribution. However, because of the intrinsic difficulty to numerically simulate the TIG-dressing process due to the high coupling between fluid and mechanical analysis, the effects of a weld toe remelting in terms of residual stress redistribution is hardly quantified in literature. The present paper is aimed to analyse the influence of TIG-dressing process on metallurgical and mechanical properties of a steel T-joint. Finally, a numerical model, recently published in literature, was used to quantified the residual stress redistribution. © 2018 The Authors. Published by Elsevier B.V. Peer-review under responsibility of the Gruppo Italiano Frattura (IGF) ExCo.

© 2016 The Authors. Published by Elsevier B.V. Peer-review under responsibility of the Scientific Committee of PCF 2016. Keywords: Welding; TIG-dressing; Modeling; Numerical simulation; Residual stress, Phase transformation

Keywords: High Pressure Turbine Blade; Creep; Finite Element Method; 3D Model; Simulation.

* Corresponding author. Tel.: +39-0444-998769; fax: +39-0444-998888. E-mail address: paolo.ferro@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.2018.06.012 * Corresponding author. Tel.: +351 218419991. E-mail address: amd@tecnico.ulisboa.pt 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-review under responsibility of the Gruppo Italiano Frattura (IGF) ExCo. * Corresponding author. Tel.: +39-0444-998769; fax: +39-0444-998888. E-mail address: paolo.ferro@unipd.it