NUMERICAL AND FAILURE ANALYSIS ON THE DRAWING OF A CIRCULAR CYLINDRICAL CUP

The incremental theory of plasticity is applied in conjunction with fi nite elements for modeling of the circular cylindrical cup. A punch/di e system is prescribed such that a circular blank is displaced at cons tant increments of 0.005 mm until a cup 16 mm deep is formed. Based on the strain energy density failure criterion, failure initiation accom panied by large dilatation is located by the maximum of the minimum lo cal strain energy density function, (dW/dV)max/min, while yielding ini tiation accompanied by large distortion is located by the maximum of t he maximum strain energy density function, (dW/dV)max/max. For a punch displacement of 16 mm, (dW/dV)max/min is near the critical value (dW/ dV)c of the metal sheet which suggests the possibility of fracture ini tiation. The influence of material drawability and punch movement on t he rate of cup formation could be evaluated from analytical simulation of the deep drawing process. Computer software developed in the prese nt study can also be applied to evaluate the drawing characteristics o f non-axisymmetric cups.