Coupled Eulerian Lagrangian finite element modeling of friction stir welding processes

A 3-dimensional localized finite element model (FEM) is developed to predict likely conditions that result in defect generation during friction stir welding (FSW). The workpiece is modeled using Eulerian formulation, while the tool is modeled using Lagrangian. Coulomb's frictional contact model is adopted to define the tool workpiece interaction, while the welding speed is defined by material inflow and outflow velocities. The numerical results show that the coefficient of friction has a major effect on void formation; the lower the friction coefficient is applied, the larger the void is formed. Furthermore, welding using force control (FC) at lower welding speed results in smaller void size and wider plastic zone, leading to higher quality weld.