Effect of Pre-deformation on Structural Finite Element Analysis of Mild Steel Parts

The deformation behavior of mild steels was discussed through analyzing a typical stress-strain curve obtained from standard tension tests. Material parameters were calculated from the stress-strain curve and a power-law model was developed for this typical mild steel. Based on the calculated material parameters, material property change with pre-deformation was studied and new stress-strain curves were developed for this mild steel after different pre-deformation. A rectangular tube model related to different pre-deformation magnitudes was created using LS-DYNA. The deformation behavior of this rectangular tube under four different basic loading conditions - tension, compression, bending, and torsion - was investigated through finite element analyses. The variation of internal energy and reaction force with the magnitude of pre-deformation and subsequent structural deformation was studied. It was found that the effects of pre-deformation on the performance of the tube are different from various loading conditions. Both internal energy and reaction force of the pre-deformed tube are dependant on loading conditions and pre-deformation magnitudes. The effect of pre-deformation on subsequent structural FEA is not always significant but only related to a specific range of pre-deformation followed by a certain structural deformation.