Modelling friction stir welding with thermally coupled fluid dynamics

Abstract
The computational fluid dynamics approach for high velocity deformation processes as friction welding [1] or friction stir welding can successfully predict certain process aspects including microstructure development, if the thermal behaviour is included properly. We model the solid state material flow in the thermomechanically affected zone of the friction stir process using the Navier Stokes equations for an incompressible non Newtonian fluid field representing the ideally plastic material movement. Viscosity is related to the ideally plastic flow stress depending on temperature and strain rate.