Analysis, simulation and experimental study of electromagnetic forming of titanium bipolar plate with arc-shaped uniform pressure coil

In the electromagnetic forming (EMF) titanium bipolar plates (BPPs), a reasonable coil structure can provide higher forming efficiency and repeatability. An arc-shaped uniform pressure coil (UPC) is proposed, and an efficient and reliable multiphysics sequentially coupled analytical model is established. Through the LS-DYNA numerical model and the fitted current curve obtained from experiments, the predictive capabilities of equivalent circuit parameters and dynamic phenomena are verified, and the rationality of the magnetic shielding assumption and magnetic flux uniform distribution are evaluated. Starting from the durability and forming efficiency of the coil, the optimal coil geometry in analytical form is constructed. The study found that there is an optimal solution for the height of the primary coil, wire thickness, primary and secondary side gap, which are 18.3 mm, 2.7 mm, and 3.2 mm, respectively. Based on this, under the discharge capacitor of 100 μF, acceleration distance of 2 mm, and driven by 0.3 mm thick Cu110, a TA1 titanium BPP with a channel depth-to-width ratio of 0.53 was successfully manufactured. Its maximum thinning rate is 18.2%, the maximum fluctuation rate does not exceed 2.5%, and the filling rate of the channel above 95%. Overall, this study provides theoretical basis and reference for the design of UPC in EMF for BPPs.