While the formability is important and indispensable for success in very complicated sheet metal
forming, it seems that few studies has been carried out about the formability of sheet metal at the high strain rate.
The present experimental results report that the elongation is dependent on the crosshead speed in tensile tests. In
this paper, the tensile elongation has been obtained from various steel sheets for an auto-body at the intermediate
strain rate. The strain rate in the experiment is ranged from 0.003/sec to 200/sec. The experimental result
demonstrates that the tensile elongation does not decrease as the strain rate increases. This tendency has varieties
depending on the microstructure and forming history of sheet metal. Some high strength steels have the tendency
that the tensile elongation increases as the strain rate increases, while o thers not. This phenomenon is very important
not only in sheet metal forming but also in the crashworthiness evaluation to predict the fracture and tearing of sheet
metal members.
Issue Date
2004
Keywords
Elongation; Formability; Intermediate strain rate; Strain rate hardening; Dynamic material test