A Study of the Strain Distributions and Strain Histories in Axisymmetrical Stretch-Forming

The strain distributions and strain histories in the axisymmetrical sheet metal forming process have hitherto been difficult to study owing to the lack of a succinct system of representation. The use of a triangular coordinate system to represent the strains in axisymmetrical sheet metal products is explained. Strain distributions and strain paths in sheet steel products are presented for processes involving variations in blank diameter, load on the pressure plate and punch profile radius. It is shown, by studying the growth of draw-in, that the effect of an increase in blank diameter is the same as that of increasing the load on the pressure plate. The various effects of a change in the punch profile radius are also discussed through the diagrams showing the strain distributions and strain paths.