This warning should only be taken into account of a self-impacting interface.
When simulating auto-contact, it is strongly advised to use a minimum gap of at least one half of
the smallest segment edge. The message means that at least one element on the main
side has a side length less than twice the GAP, and there is an
over-stiffening
risk.
WARNING ID: 94
** WARNING IN INTERFACE GAP
INPUT GAP 1.7
HOWEVER GAP IS RECOMMENDED TO BE LESS THAN 1
Figure 1
illustrates a self-impacting interface for which the GAP equals
half the side length of an element. If this element is compressed more than 50%, the
red node enters into the gap of the neighboring element; a self-contact is then
detected which should not be the case. This leads to over-stiffening of the
structure.Figure 1. Recommended Gap When Modeling Auto-Contact
If the side length, L of an element is lower than the GAP,
a self-contact will even be computed from the beginning of the computation.
Such a situation can be accepted if it is an exception, but not for frequent cases over the self-impacting interface. It is possible to localize the source of this message by using a pre-processor and selecting the elements through size criteria.
