Abstract
The coupled themomechanical modeling of the friction stir welding (FSW) process is
a challenging process when typical finite element methods are used. In this study
we use a meshfree technique to model the material flow during the FSW process.
We employ the Element Free Galerkin Method (EFG) as approximation method. A
mortar contact is used to account for the stirring effect and heat generation from the
frictional contact. We use a two-way adaptive method (rh-adaptive) during the coupled
thermomechanical process to overcome potential numerical problems arising from the
extensive mesh distortion and material deformation. This means, the mesh is globally
refined with perusing an anisotropic tetrahedral mesh (h-adaptive). At the same time, a completely new mesh is built based on the old mesh (r-adaptive). Finally, we validate
our simulation results with comparison to experiments done on 6mm thick Aluminum
(AA2024-T351) sheets with a Triflat conical threaded tool. The comparison of the
numerical results and experiments show good agreement. The next step after this
study is to use the deformation and temperature history from the thermomechanical
simulation to predict the final micro-structure after the welding process where the
dynamic recrystallization is responsible for the micro-structure evolution.
