Formability Limit Curves under Stretch-Bending

A common strategy for stabilizing the greenhouse gas concentrations in the atmosphere was the introduction of new emissions limits for cars, and light commercial vehicles. For that reason the automotive industry is facing new challenges in order to fulfill these considerations. One of the strategies attained, is to employ new grades of Advanced High-Strength Steel (AHSS) to replace conventional steels in vehicle’s body structures. These changes are intended to reduce the estimated total weight and increase fuel efficiency of vehicles. The main focus of this research is to derive a stability model which can encounter the enhanced formability obtained when simultaneous bending and stretching are applied to a sheet metal. Since experimental data is already available, it will be used for validation purposes. A sensitivity analysis in terms of different punch radii during the Nakazima test will be presented.