Development of finite element method for flow forming of 5919 steel.
Date of Issue2009
School of Materials Science and Engineering
Singapore Institute of Manufacturing Technology
We investigated the precision of the Finite Element Method (FEM) simulation using Deform 3D on flow forming of Steel 5919 cup with uniform diameters throughout the cup height. The stress-strain behaviour of the sample was determined through upsetting in order to determine the strength coefficient and strain hardening coefficient, which were then used to construct the stress-strain curve of the sample. By considering only plastic deformation occurring on the workpiece and assuming rigid behaviour of the rollers and mandrel, the FEM simulation was performed to see how accurate it is to the actual process. The precision of the simulation was evaluated by verifying the simulation results with the actual results in terms of inner and outer diameters of the cup, as well as the yield strength of the flow formed cup. The comparison showed that the simulation suggested much larger diameter fluctuation as compared to the actual measurement while it was still able to capture the trend of the fluctuating diameters. Moreover, the simulation suggested that the yield strength (calculated from the strain) is much higher than the actual finding. These discrepancies were then evaluated to give a rough measure of the amount of elastic deformation from the total deformation. The significant gap between the results suggests that the workpiece experienced significant elastic deformation such that the fully rigid plastic model is not good enough as an approximate. The low strain hardening coefficient is also responsible for the significant discrepancy between the effective strain from the simulation and the experiment.
Final Year Project (FYP)
Nanyang Technological University