Modeling and Optimization of Shear Strength of the Welded Joint Produced by Ultrasonic Welding of Copper Wire to Aluminum Sheet

Ultrasonic welding is a subset of frictional solid-state joining processes. This process, with its ability to join thin and dissimilar metallic materials, has been noticed by researchers. On the other hand, the dissimilar joining of aluminum and copper wires and electrodes in the battery of electric cars and hybrid electric cars to reduce the cost and weight of the car structure has been raised as one of the important industrial challenges. Therefore, in this research, ultrasonic welding of dissimilar joining of Al 1050 sheet with a thickness of 0.2 mm and copper wire with a cross-sectional area of 2.5 mm² was studied. For this purpose, the experiment was designed based on the response surface methodology (RSM) and Box-Behnken design (BBD). Static pressure, welding time, and vibration amplitude were selected as input variables in three levels. Then, the tensile test was performed on the specimens to evaluate the shear strength of the welded joint. The results of ANOVA showed that the linear and second-order effects of static pressure and vibration amplitude have the greatest effect on the shear force. Also, the regression model of shear force was extracted as a function of linear, interactive, and quadratic terms from the input variables. Finally, the optimal combination of input variables to achieve the maximum shear force was determined with a desirability of 0.935, and by performing the verification test, the competence of the regression model to predict the shear force was confirmed.