A tangential force can be generated when a penetrated node is sliding without friction. This
behavior is due to the gaps overlapping around the edges. Figure 1 illustrates that by the cylindrical gap around the edges, the force
is no longer normal to the shell mid-surface.Figure 1. Generation of Tangential Force
Note: No problems were observed in crash simulations, but in metal forming where
friction is very important this can seriously decrease the accuracy.
Comments
It is always advised to
post-process the contact forces. If they are too large, taking into account the
physical understanding, the model must be checked.
To post-process the forces
for symmetric contact, the interface can be split into four interfaces. For example,
for two parts A and B, you can create:
