Modelling of Metal Deposition

Modelling and simulation of metal deposition (MD) can be seen as an extension of the welding simulation with added complexity for the modeller. The aim of the work presented in this paper is to enable simulation of metal deposition for large three-dimensional components. The process that is used in this study is Gas Tungsten Arc Welding with solid wire. A physically based material model is used to characterise the material. This allows for a material description over a large strain, strain rate and temperature interval.

To alleviate the process of generating a suitable mesh for the component and the material to be added, a method for using a non-matching mesh between the base and the filler material has been developed, see Figure 1. This has been implemented by using a contact condition that keeps the nodes of the filler material fixed on the surface of the base materials elements. Heat transfer is allowed through the contact area. The addition of filler material is done by activation of elements. Due to large deformation the position of the filler material nodes are adjusted before activation. Also, a logic for adjusting the volume of the filler material according to given process parameters is implemented. The input variables to this logic are the same as to the physical process; the wire diameter and the feed rate.

Simulated results will be validated with experiments and also compared with results obtained from simulations performed with matching finite element meshes. The measurements available from experiments are temperature history at a selected position and deformations measured at four selected positions. The proposed method is believed to reduce the modelling work considerably for metal deposition and multi-pass welding simulations.

Figure  SEQ "Figur" \*Arabic 1: MD bead on plate with non-matching mesh, the fringe scale shows the temperature during cooling.