Analytical solution of the tooling/workpiece contact interface shape   during a flow forming operation
  Flow forming involves complicated tooling/workpiece interactions. Purely analytical models of the tool contact area are difficult to formulate, resulting in numerical approaches that are case-specific. Provided are the details of an analytical model that describes the steady-state tooling/workpiece contact area allowing for easy modification of the dominant geometric variables. The assumptions made in formulating this analytical model are validated with experimental results attained from physical modelling. The analysis procedure can be extended to other rotary forming operations such as metal spinning, shear forming, thread rolling and crankshaft fillet rolling. 
M. J. Roy, D. M. Maijer, R. J. Klassen, J. T. Wood, E. Schost
physics.class-ph