from the conferences organized by TANGER Ltd.
During the pressing of sheet metal parts, cracks may form around the holes that weren't predicted by numerical simulations. These cracks are caused by the partial depletion of the forming capacity at the edges of the hole due to the preparation technology used, most often shearing. The aim of this article is to refine the simulation models by introducing boundary conditions to describe this condition. The Hole Expansion Test (HET), described in ISO 16630 and currently the only worldwide standardised method for determining the sensitivity of a material to edge crack formation, is used to determine the limiting deformation at the edge of the material. Materials commonly used in the automotive industry were chosen for the experiment. Holes were made in samples of each material according to ISO 16630 by shearing, laser cutting, and electro-discharge machining. The testing was carried out according to ISO 16630 at room temperature and the specimens were evaluated manually just before failure. The results obtained were evaluated and compared with theoretical premises. By refining simulation models and introducing boundary conditions that account for the depletion of forming capacity at the edges of holes, manufacturers can better predict and prevent the formation of cracks during the pressing of sheet metal parts. This can improve the quality and durability of automotive parts and lead to safer and more reliable vehicles.
Keywords: Sheet metal forming; hole expansion test; sheared edge formability; fracture criterion; edge plasticity evaluation© This is an open access article distributed under the Creative Commons Attribution License which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.