Abstract: The wrinkling strength of shell in cup deep-drawing process without blankholder through a conical die is deduced by using the well-known energy method. The formula mirrors the effect of material properties, radial and circumferential bending, varying thickness and work-hardening on the wrinkling strength. Predicted limiting drawing ratios without wrinkling on the basis of the strength are completely in agreement with the experimental results of cup deep-drawing without blankholder through a conical die, which are obtained by Sowerby et al. Who used three metals in three different sheet thicknesses. Their maximum relative error is not more than eight percent. The study method is also suited to analyze cirumferential compressive instability in the area of hanging in the air between punch and die for axisymmetrical no-straight wall parts.

Key words: Bending, Deep-drawing, Instability, Wrinkling, Voxelization Distance field Velocity field Heterogeneous information Model fusion