Title: An Inverse Problem in Welding
Palestrante: Philippe Le Masson, Professeur des Universités, Responsable de la filière Energétique de l'UFRSSI
Université de Bretagne Sud - Lorient, France
LOCAL: Sala G-219B, Centro de Tecnologia, Ilha do Fundão
DATA: 29/10/2015 (quinta-feira)
ABSTRACT: The work which is presented in this paper deals with the estimation of the evolution of a fusion front shapes. This front motion is the result of the application of a TIG welding process on a 316L stainless steel. In this study, a particularity is that the process does not move which generate axisymmetric phenomena. The estimation is based on the iterative regularization method. In this last, the various constituents are obtained from numerical resolutions. Indeed, the direct problem, the variational problem and the adjoint problem, classically associated to this method, are solved by the finite element method. The originality of this work is to deal solely with the heat transfer in the solid phase. To track the evolution of this solid domain during fusion, the ALE moving mesh method (Arbitrary Lagrangian Eulerian) has been chosen. The numerical developments are carried out with the commercial \Comsol Multiphysics" code coupled with the Matlab software. The estimation method has been validated in a previous study which used theoretical data. In the present study, the experimental data are : temperatures measured by thermocouples in the solid phase, the temporal evolution of the liquid-solid limit observed on surface by a fast camera, and the maximal dimensions of the melted zone measured on macrographs. These experimental data are also compared with numerical results obtained from a heat and fluid flow model, taking into account surface tension effects, Lorentz forces, and the deformation of the melt pool surface under arc pressure.