A fundamental study on the hardness-strain in bent cross-section of thin steel panels during the hemming process with a comparison between experimental and numerical approach

Abstract

The objective of the current study is to investigate the mechanical properties of the 180° bending edge of a hot-dip galvanized steel panel with a flat surface edge (as the JISG3302 stander). Our study investigated the relationship between hardness and strain at the cross-section of the panel through numerical simulations. Hardness tests are carried out on the machined cross-sections of the panel, subsequently further hardness and strain conversion equations (based on the ASTM-E140.19(2013) standard), The hardness and strain tests offer valuable insights into the materials’ deformation resistance and its capacity to withstand external loads. The results obtained from these tests, including the hardness and strain values, can be used to develop conversion equations that facilitate the evaluation of the hemmed panel's strength with respect to the metal material used. In addition, the strain results are compared with the numerically simulated strain results (utilized DEFORM Ver.11) to provide a basis for subsequent simulation works. This approach allows for a more comprehensive understanding of the mechanical properties of the cross-section panel and could also validate simulation results: on the reliability and accuracy of the hardness test work. Consequently, this approach allows to predict the behavior of panel material under specific loading conditions in the hemming process. which can be of utmost importance in industrial applications.