Finite Element Analysis and Experimental Investigation of Sheet Metal Stretching

The finite element method was used to obtain the stress and strain distributions in sheet metal on nonaxisymmetric flat punch heads in stretching. Displacement boundary conditions were assumed. The experimental investigation was carried out by stretching securely clamped grid blanks with suitable punch heads; boundary displacements and strains were obtained from the observed deformation pattern on punch heads. A comparison with an experiment in terms of effective strain and thickness strain distributions and strains along the longitudinal axis reveals excellent agreement. The finite element method was also applied to bore expanding in a circular plate. Strain distributions were obtained for two types of materials, one isotropic and the other material having thickness anisotropy. The results showed excellent agreement with exact solution and experimental results.