PREDICTION OF NECKING AND WRINKLING IN SHEET-METAL FORMING

Two approaches are presented to predict failure in the sheet-metal forming of some simple geometries. To predict necking, the results of Continuum Damage Mechanics (CDM) are employed, the Gurson model being utilized as a constitutive equation and the damage variable being used as pointer to the endangered area. To represent the failure of anisotropic metals, an extension of the Gurson model is suggested. The simulation of wrinkling starts out from the study of a one-dimensional case, the buckling of a long column. The role of geometric imperfections is discussed. The approach is applied successfully to the simulation of deep-drawing processes.