Limit Analysis of Hollow Disk Forging—Part 1: Upper Bound

An upper bound analysis for hollow disk forging is presented. Flow is described by a kinematically admissible velocity field which accounts for bulging of the inner and outer surfaces. The friction stress is assumed to be constant across the entire platen-hollow disk interface. Analytical predictions include the relative neutral radius, a bulge parameter and the relative average pressure all in terms of friction and hollow disk geometry. An improvement is observed over previous parallel velocity field solutions.