Numerical analysis of vibration effect on friction stir welding by smoothed particle hydrodynamics (SPH)

Abstract

A numerical analysis is improved to study the effect of vibration on temperature history, heat generation, and mechanical properties during the friction stir welding process with different welding speeds. In this investigation, smoothed particle hydrodynamics (SPH) was applied to improve the 3D numerical analysis for simulation of the friction stir welding (FSW) process and friction stir vibration welding (FSVW) under different welding speeds. According to the experimental analysis, the grain size of the FSVW-ed sample is finer compared with that of the FSW-ed sample. The analysis was validated through a comparison of the simulated thermal cycles with the experimental results. There was a close agreement between FEM and experimental values. The results indicated that the vibration increased the mechanical properties such as von Misses stress and also thermal properties of the FSW-ed sample. The vibration in the FSW process can lead to an enhanced plastic material flow and also improve the weld quality by enhancing the plastic material flow near the tool. The shear zone volume (SZV) develops from 289.56 mm3 for the FSW process to 367.34 mm3 for the FSVW process. It was found that the axial forces, traverse force, and tool torque with respect to different steps (plunging, preheating, or dwelling time and traveling) in FSVW is lower than those in the FSW.