Thickness distribution and mechanical property of sheet metal incremental forming based on numerical simulation

The thickness distribution and mechanical property of a truncated pyramid processed by incremental forming were investigated based on numerical simulation and tensile tests. A finite element method (FEM) model was set up and then experimentally verified. The tool path of the simulation model was assured to be the same with that of the real process by adding the displacement constraints on the forming tool. Afterwards, the sine law used to predict the final thickness was verified, but it was only applied to the region mainly subjected to pure stretching deformation. Additionally, the relation between the tool path and the minimum thickness as well as its location was discussed. The result indicates that the minimum thickness is much related to tool diameter if a traditional tool trajectory is employed, and its location is largely determined by step depth. Finally, tensile tests with specimens taken from the formed pyramid were carried out. It is indicated that the plasticity of the material decreases sharply while the strength increases markedly owing to the significant work hardening effect during ISF process.