Numerical and experimental study on electrohydraulic forming process

Electrohydraulic forming (EHF) is one of the high-speed forming process that uses high-voltage discharge in liquid. Shockwave resulting from the discharge is generated between two electrodes in liquid and it deforms the blank into the die. When the blank is deformed in a very short time, the formability is enhanced and springback can be reduced. Furthermore, in electrohydraulic forming, the blank has no bouncing effect that happens in other high-speed forming process. Therefore, it is possible to deform the blank into a complex shape with only one operation. In this paper, numerical and experimental study of electrohydraulic forming was performed using an Al 6061-T6 sheet material. Numerical model was formulated in LS-DYNA program. ALE (Arbitrary Lagrange-Eulerian) scheme was applied to create the elements of the fluid parts and structural parts were modelled using shell elements. From the results of the numerical simulation, it was observed that the pressure of the fluid parts was increased by the electric energy and the movement of the water part could deform the blank into the die. In addition, electrohydraulic forming apparatus was developed and experiment was carried out using an equipment of 32 kJ capacity and conical die. Comparison of the numerical and experimental results was also conducted on the bulge height of the blank and it also showed similar tendency in relation to the deformed shape.