Investigation of Sheet metal Deformation Subjected to Electrohydraulic forming using Experimental Observations and Numerical Simulation with SPH Method

Electrohydraulic forming (EHF) is a high velocity sheet metal forming process in which two electrodes are positioned in a water filled chamber and a high-voltage discharge between the electrodes generates a high-pressure to form the sheet metal. In this work, extensive experimental tests are carried out (up to 3.2 kJ) to investigate the deformation behavior of brass sheet by using EHF. To explain different aspects of sheet deformation, Smoothed Particle Hydrodynamics (SPH) formulation is coupled with Finite Element Method (FEM) in LS-DYNA and applied for simulation. In order to model the electrical discharge process, two different approaches are implemented. In the first approach, electrical discharge energy is converted to equivalent TNT mass. In the second approach electrodes gap is replaced by a plasma channel and electrical discharge energy is leaked to it. Finally, deformation history (displacement, velocity, strain and strain-rate) at different locations of sheets are presented. The results indicate that (under the conditions used in this study) the maximum of velocity and strain-rate are reached to 250 m/s and 3800/s respectively.