A CLOSED-FORM NON- LINEAR SOLUTION FOR PLASTIC FLANGE WRINKLING OF CIRCULAR PLATES IN DEEP DRAWING PROCESS

This paper deals with two-dimensional plane stress wrinkling model of a plastic annular plate. Based on energy method and the nonlinearity of strain-displacement law, a bifurcation function in polar coordinates is derived analytically. This technique leads to the critical conditions for the onset of the plastic wrinkling of flange during the deep drawing process. To find this solution, the Tresca yield criterion along with plastic deformation theory are employed. The material of the plate is assumed to behave perfectly plastic. This analytical closed-form solution is obtained by considering the nonlinearity of the material and geometry, simultaneously. The main advantage of the proposed solution is better agreement to the other researchers's experimental results. Moreover, the influence of the blankholder upon wrinkling, and also on the number of the generated waves, can be quantitatively predicted by the suggested scheme.