A method for process parameter optimization of simultaneous double-sided friction stir welding using a heat transfer model

This paper presents a method for optimizing process parameters of simultaneous double-sided friction stir welding (SDS-FSW). Building upon the thermal pseudo-mechanical mechanism and computational solid mechanics, a heat transfer model is formulated first to investigate the coupling effect of the heat sources and verified by existing experimental data of another study. The nonlinear surrogate models are then constructed to relate three process parameters with maximum temperature at two selected locations and heat-affected zone (HAZ) length, using the data generated by the heat transfer model. Consequently, the spindle speed, feed rate, as well as distance between two welding tools are optimized by minimizing the input energy subject to the constraints in terms of the maximum temperature and HAZ length. Compared to the initial parameters, the optimal case allowed the welding parameters including the HAZ length, input energy, and welding time to reduce by 5.71%, 37.46%, and 20.32%, respectively, thereby having the potential applicability to achieve relatively high welding quality and efficiency.