Please cite this article in press as: J. Caixas, et al., Weld distortion prediction of the ITER Vacuum Vessel using Finite Element simulations, Fusion Eng. Des. (2013), http://dx.doi.org/10.1016/j.fusengdes.2013.02.101 ARTICLE IN PRESS G Model FUSION-6726; No. of Pages 4 Fusion Engineering and Design xxx (2013) xxx–xxx Contents lists available at SciVerse ScienceDirect Fusion Engineering and Design journa l h o me page: www.elsevier.com/locate/fusengdes Weld distortion prediction of the ITER Vacuum Vessel using Finite Element simulations Joan Caixas a,∗ , Julio Guirao b , Angel Bayon a , Lawrence Jones a , Jean Franc¸ ois Arbogast a , Andrea Barbensi c , Andres Dans a , Aldo Facca d , Elena Fernandez a , José Fernández a , Silvia Iglesias b , Marc Jimenez a , Philippe Jucker a , Gonzalo Micó a , Javier Ordieres b , Jose Miguel Pacheco a , Roberto Paoletti e , Gian Paolo Sanguinetti c , Vassilis Stamos a , Massimiliano Tacconelli e a F4E, c/ Josep Pla, n.2, Torres Diagonal Litoral, Edificio B3, E-08019 Barcelona, Spain b Numerical Analysis Technologies, S. L., Marqués de San Esteban 52, Entlo, 33209 Gijon, Spain c Ansaldo Nucleare, Corso F.M. Perrone, 25, I-16152 Genoa, Italy d Mangiarotti, Pannellia di Sedegliano, I-33039 Sedegliano (UD), Italy e Walter Tosto, Via Erasmo Piaggio, 72, I-66100 Chieti Scalo (CH), Italy h i g h l i g h t s  Computational simulations of the weld processes can rapidly assess different sequences.  Prediction of welding distortion to optimize the manufacturing sequence.  Accurate shape prediction after each manufacture phase allows to generate modified procedures and pre-compensate distortions.  The simulation methodology is improved using condensed computation techniques with ANSYS in order to reduce computation resources.  For each welding process, the models are calibrated with the results of coupons and mock-ups. a r t i c l e i n f o Article history: Received 14 September 2012 Received in revised form 16 January 2013 Accepted 18 February 2013 Available online xxx Keywords: ITER Vacuum Vessel Weld distortions Finite Element Calibration a b s t r a c t The as-welded surfaces of the ITER Vacuum Vessel sectors need to be within a very tight tolerance, without a full-scale prototype. In order to predict welding distortion and optimize the manufacturing sequence, the industrial contract includes extensive computational simulations of the weld processes which can rapidly assess different sequences. The accurate shape prediction, after each manufacturing phase, enables actual distortions to be compared with the welding simulations to generate modified procedures and pre-compensate distortions. While previous mock-ups used heavy welded-on jigs to try to restrain the distortions, this method allows the use of lightweight jigs and yields important cost and rework savings. In order to enable the optimization of different alternative welding sequences, the simulation methodology is improved using condensed computation techniques with ANSYS in order to reduce computational resources. For each welding process, the models are calibrated with the results of coupons and mock-ups. The calibration is used to construct representative models of each segment and sector. This paper describes the application to the construction of the Vacuum Vessel sector of the enhanced simulation methodology with condensed Finite Element computation techniques and results of the calibration on several test pieces for different types of welds. © 2013 Elsevier B.V. All rights reserved. 1. Introduction The ITER VV sectors have to be manufactured to tight tolerances (≤±10 mm) on the overall profile to allow the sectors to be welded later in situ with the other VV sectors [5], without the production ∗ Corresponding author. Tel.: +34 933201144. E-mail addresses: joan.caixas@f4e.europa.eu, jcaix@hotmail.com (J. Caixas). of a full scale prototype to assess the welding distortions. Achieve- ment of these tight tolerances is made more difficult by the nature of the austenitic steel 316L IG (ITER Grade), which exhibits high welding distortion due to thermal conductivity combined with a high coefficient of thermal expansion. It has been developed a suc- cessful methodology for modelling weld processes [1] in order to predict welding distortion and residual stresses (Fig. 1). Further- more to optimize the manufacture sequence [3,6] and methods, the method is able to assess the effect of using different sequences 0920-3796/$ – see front matter © 2013 Elsevier B.V. All rights reserved. http://dx.doi.org/10.1016/j.fusengdes.2013.02.101