Formation of the periodic material flow behaviour in friction stir welding
Hao Su, Tao Wang, Chuansong Wu
Abstract
A two-dimensional computational fluid dynamics model is established to verify the correlation between periodic material flow and tool eccentricity during friction stir welding (FSW) process. In the model, the marker material is tracked by employing the Volume of Fluid technique. Besides, a novel boundary condition is proposed, which is not only non-uniformly distributed around the pin but is also connected with the real-time orientation of tool eccentricity. Finally, the dynamic evolution of marker material with the pin rotating is analysed, and the comparison between calculated and measured distribution of deposited marker material is carried out. The result demonstrates that tool eccentricity can be considered as the original mechanism for the formation of periodic material flow behaviour in FSW.