An In-Depth Study on the Impact of Test Parameters on the Erichsen Index and Punch Force

In this paper, the Erichsen index (EI) values of the DC04 steel sheets were obtained both experimentally and through finite element analysis. The influences of punch size, punch speed, and thickness level of the sheet on the punch force, EI and fracture strains were examined. The design of the experiments was created using the Taguchi method, and the influences of the factors on the EI value were detected numerically with an analysis of variance (ANOVA). It was observed that the most effective parameter on the EI is the punch diameter. Additionally, it was noticed that the fracture strain and the Erichsen index increased with higher levels of thickness, and the punch speed showed no appreciable impact on the EI value. It was found that as the punch diameter decreased, the impact of sheet thickness on ES and fracture strain increased. The punch force increases almost linearly with both the punch diameter and sheet thickness. The effective strains at the onset of crack formation were calculated mathematically, and simulations were conducted based on these data. The simulation results of the Erichsen tests show strong consistency with the experimental findings, with the Mean Absolute Percentage Error not exceeding 3.5%.