The study of stress state in indentation of a flat punch with rounded edge in axisymmetric backward extrusion

الملخص EN

Analytical solution have to obtained of contact problem for indentation of flat punch with rounded edges in axi symmetric extrusion to both surface pressure and interior stress fields for a given die shape at different velocity fields.

Both sliding friction and partial slip condition must be concluded in the equation of metal flow for extruded material taking into consideration von Mises yield criterion and the complicated high elastic contact stress in the flat and rounded edges dies.

An experimental method using prototype sample of photo elastic material to determine the effect of rounded edges on the stress distribution in the contact zone.

A numerical method used programming for solving the analytical equations of metal flow using quick basic and comparing the theoretical with the experimental results.

A kinematically admissible metal flow cylindrical velocity using strain rate of plastic flow has been proposed to obtain the load of contact on the elastic punch face during the axi-symmetric backward extrusion.

The theoretical results predict the forming force , rule of friction , area reduction and the metal flow quite satisfactorily when compared with the experimental results.