A computation of tangent stresses of sheet via slipping in micro structure of material when forming sheet by spit technology

Abstract

Slipping of atoms in lattices is always the main reason that yields the plasticity deforming in crystal structure of the material (Jacob Lubliner 2009). This paper attempts to compute strains and stresses by theoretical means from the modification in micro structure of the sheet workpiece when it is formed by the pressure of a spherical non-cutter tool on it in Single Point Incremental Forming (SPIF) technology, a new method of forming sheet in the recent years. From the outside macro deforming we define the displacement of atom in the interstice of the theoretical crystal of the material. The shear stress on the surface of the crystal is really the behavior of the material under the outside forming force. Ideal structure of crystalline lattices inside material and absolute hardness of the forming tool are supposed in this paper.