TREATMENT OF CONTACT TRACTION AT THE DIE - WORKPIECE INTERFACE FOR THE ELASTIC ANALYSIS OF DIE DEFORMATION

Abstract

A method to calculate the contact traction on the die-workpiece interface is proposed. A systematic method for performing the elastic finite element analysis of the die deformation by using the information obtained from the finite element analysis of the workpiece deformation is proposed. The proposed method can be applied to both the two-dimensional and three-dimensional analyses of die deformation independently of the friction modelling and the constitutive equations. A rigid-plastic finite element analysis of workpiece deformation is carried out for the upsetting of a cylindrical workpiece. In order to check the validity of the present method for both flat and curved contact surfaces, the elastic finite element analysis of die deformation is then performed for flat square block forging as well as for a bevel gear forging (Yoon and Yang, Int. J. Mech. Sci. 32, 277-291, 1990) [8]. From the computation it is shown that the error due to the transfer of data from the workpiece mesh to the die mesh does not influence appreciably the elastic deformation of the die. The proposed method can be applied to arbitrarily curved die geometries in three-dimensional metal forming problems.