A novel formability test method for electro-magnetic forming of aluminium sheet

This study develops an EMF formability testing process, for investigating the forming limit of aluminium sheet, at high strain rates up to 5000 s ^-1 Changes in the hole size and the distance between these two holes, In a sheet blank, can generate different strain paths, at high strain rates. By plotting the different simulated strain paths and limit strains, measured using the proposed formability test method, the forming limit diagram, at high strain rates, was obtained. This Is useful in the prediction and prevention of fracture. The EMF experiment involved propelling an aluminium alloy AI5052-H32 sheet of 0.5 mm thickness at a punch, using a flat spiral electromagnetic coil. The finite- element software, LS-DYNA, was used for simulating the formablllty test process, for various strain paths. The experimental results of limit strains agreed well with the simulated results.