Abstract
Hydroforging is a hybrid forming operation whereby a thick tube is formed to a desired geometry by combining forging and hydroforming processes. Through this process hollow structures with high strength-to-weight ratio can be produced for applications in power transmission systems, etc. In this process, a thick tube is deformed by pressurized fluid contained within the tube using a multi-purpose punch assembly, which is also used to feed tube material into the die cavity. An analytical model for determining pressure-feed loading paths is formulated for the hydroforging process. The model is derived based of plasticity theory and deformed shape evolution. Stepwise solution schemes are used to calculate instantaneous pressure, material feed, stresses, strains, and other geometrical parameters. The derived analytical model can be used for preliminary process design before embarking in extensive FE simulations. The model is also ideal for rapid establishment of loading paths for different geometrical configurations. Thus, time spent in trial-and-error finite element simulations carried out to determine optimal loading path for a specific part can be reduced significantly. (C) 2014 Published by Elsevier Ltd.