Is there a way to reduce the penetration problem?

If there is a large penetration of the blank into the rigid tools, there are several ways to address this problem, some solutions are provided below:

a) Use a larger value for the penalty coefficient SLSFAC (the first parameters in the card of *CONTROL_CONTACT). Usually this value is chosen between 0.1 and 0.01. It should be noted however that too large value of this parameter can cause contact instability.

b) Use a different contact. If the mesh for the rigid tools is finer than the mesh for the blank or the slave side, it is better to use another contact: *CONTACT_FORMING_SURFACE_TO_SURFACE. In this contact, there is no difference in the slave and master surface, and both surfaces are treated equally. It is found that this contact can reduce the penetration problem. This contact is more expensive than the other contact, it is suggested that this contact is used only when necessary.

c) Use constraint contact instead of the commonly used penalty method. With this contact, the blank mesh is not allowed to penetrate the rigid tools; accordingly, there is no possibility to have penetrations in the forming analysis. There is no separate contact cards for this contact, and this contact is realized by using the contact card of FORMING_ONE_WAY_SURFACE_TO_SURFACE, there is a parameter SOFT (in the Optional Card A), if we chose SOFT=4, then the constraint contact will be used during the analysis.