Numerical modeling and experimental analysis of deformation behaviors during electromagnetic flaring process of thin-walled copper tubes

Abstract

To control thinning is a challenge in traditional flaring process of thin-walled tubes. Electromagnetic forming provides a new way to expand the tubes end with uniform wall thickness, as it can produce a uniform distribution of magnetic force on tubes and easily form by one step based on adjusting the discharge parameters. In this paper, a 3D asymmetric finite element model of electromagnetic flaring of thin-walled copper tubes based on the magnetic vector potential is developed for calculating magnetic field and magnetic forces, and Newmark integration method is used to calculate the dynamic plastic deformation of tubes in the mechanical model. A sequential-coupled simulation approach is developed to analyze the deformation behaviors and the influences of different discharge parameters on deformation behaviors for electromagnetic tube flaring. The deformation height and thinning rate of thin-walled copper tubes show a positive correlation with the charge voltage and capacitance, and deformation zone maintains uniform thickness resulting in smaller thinning rate so as to reduce the trend of crack. Subsequently, some experiments are used to verify the simulation results. A comparison of simulation results and experimental results for final tubes shows a good agreement, and the measured hardness of deformation zone significantly improved after electromagnetic tube flaring.