Discrete element method, a tool to investigate complex thermo mechanical behaviour: application to friction stir welding

In material forming or cutting, the contact zone between the tool and the working piece is often very difficult to analyse because of diverse local phenomena. In the special case of FSW, a specific difficulty is the study of material mixing. In this work, the Discrete Element Method is applied as a tool to understand/propose/confirm physical scenarii involved in FSW process. A simple micro behaviour law that takes into account thermal, mechanical and material aspects is proposed and a two dimensional simulation based on this law is presented. The first results show qualitatively good agreement with real nuggets observations. One of the main advantages of DEM approach is the simplicity of the local input law compared with laws proposed at the continuous media mechanics level. Nevertheless, numerical aspect must be improved to carry out three dimensional simulations with reasonable calculation times.