IV.5 - On the Adjustment and Validation of Finite Element Models for Hemispherical Cup Forming

Abstract

The objective of the simulation of deformation process is to determine forces and power required to complete the operation, as well as the displacements, strains and stresses at every point in the deformation region during processing so that the final shape of the product and its properties, residual stresses, and formability limit can be predicted. A complete analysis of sheet metal forming problems requires solutions in both elastic and plastic regions. However, classical methods of solution, such as the uniform deformation energy method, slip line field, and slab methods usually consider rigid-plastic material and make many simplifying assumptions that limit their applicability. Accurate determination of the effects of various parameters involved in sheet metal forming process on the detailed metal flow becomes possible when the finite-element method (FEM) is introduced into the analysis of metal forming process. For any finite element model, there are many controlling variables that would affect the model performance, such as element type, number of elements, and frictional contact conditions. The output results of the finite element model are very sensitive to such variables. If the selection and/or adjustment of the model variables are correct, the obtained results are realistic, which is the main concern of any successful simulation process.