PREDICTION OF NECKING AND WRINKLING IN SHEET-METAL FORMING

Two approaches are presented to predict failure in the sheet-metal for ming of some simple geometries. To predict necking, the results of Con tinuum Damage Mechanics (CDM) are employed, the Gurson model being uti lized as a constitutive equation and the damage variable being used as pointer to the endangered area. To represent the failure of anisotrop ic metals, an extension of the Gurson model is suggested. The simulati on of wrinkling starts out from the study of a one-dimensional case, t he buckling of a long column. The role of geometric imperfections is d iscussed. The approach is applied successfully to the simulation of de ep-drawing processes.