2008 Volume 49 Issue 2 Pages 278-283
In this study, the effect of tool-modeling accuracy on a finite-element simulation of a square-cup deep-drawing process is examined. First, the accuracy of tool modeling using a conventional approach, in which polyhedral surfaces are used, is compared with that of an alternative approach, in which the quadratic parametric surfaces proposed by Nagata [Nagata, Comput. Aided Geom. D 22 (2005) 327–347] (Nagata patch) are used. It is clear that the Nagata patch yields a much more accurate tool geometry than the conventional approach with regard to the shape and normal vectors of the tool. Next, simulations of the square-cup deep-drawing process are carried out for die models with various numbers of tool elements. It was found that a polyhedral model with at least 10 divisions at the die shoulder is required to carry out accurate simulations. The simulated result of the Nagata patch model with two patches at the die shoulder corresponds well to that of the polyhedral model with more than 10 patches. From this point of view, it is concluded that the number of tool elements can be markedly decreased using the Nagata patch model. In the present case, the number of tool elements can be reduced to about 10% of that of the polyhedral model.