Numerical analysis of cooling and joining speed effects on friction stir welding by smoothed particle hydrodynamics (SPH)

This current work considers the utilization of the completely Lagrangian technique, smoothed particle hydrodynamics to improve the 3D finite element model for numerical analysis of the friction stir welding (FSW) in the air and underwater conditions. This technique was primarily applied to simulate fluid motion because of various advantages compared to conventionally grid-based methods. Newly, its usage has been developed to analyze the metal-forming analysis. The temperature history, strain and stress distributions during the FSW process in the air, as well as underwater, were considered. Besides the cooling influence, the effect of traveling speed, friction coefficient, mesh size and the mass scaling technique to find the converged model and decrease the CPU time were studied. The improved model is confirmed by comparing the numerical welding temperature with experimental outcomes. There was close compatibility between finite element analysis and experimental results. The conclusions indicated that the lower peak temperature was achieved due to higher cooling effect in underwater welding in comparison with conventional welding. Moreover, the peak temperature and strain rate decreased as traveling speed increased for both welding conditions, while stress values increased.