Determination of Dynamic Characteristics of Aluminum 1050 Sheet Using Electromagnetic Forming Ring Expansion Test

A new method based on the EMF ring expansion test has been suggested for determining the dynamic characteristics of annealed and as-received aluminum 1050 H18 sheet. The proposed method does not need any expensive hardware or data collector. After performing quasi-static (QS) tensile tests, two coils and three sets of rings were prepared. The rings were expanded by coils at different voltages, and the strains induced were measured using 2D scanners. An inverse modeling algorithm was used as a tool to determine the strain rate hardening coefficient by minimizing the difference between experimentally measured strain and that calculated from FEM simulation. The obtained strain-rate hardening coefficient of the material shows that annealed aluminum 1050 sheet is sensitive to strain rate, whereas the as-received is not. The obtained results showed that the as-received aluminum 1050 sheet depicts brittle failure behavior in both QS tensile test and high strain rate ring expansion test, but the annealed one withstands strains above 0.25 at both mentioned strain rates. The proposed method is successful in determining the flow curve of the material in sheet forming at high strain rates. Graphic Abstract