In LS-DYNA, for the following contact types:

SINGLE_SURFACE
AUTOMATIC_SINGLE_SURFACE
AUTOMATIC_GENERAL
AUTOMATIC_GENERAL_INTERIOR
ERODING_SINGLE_SURFACE

The shell thickness used for contact is governed by the following:

The smaller of two values:

a) the shell thickness (applied via *SECTION or *ELEMENT) multiplied by any scale factors.

or

b) 40% of the edge length. With edge length calculated as Min(N4-to-N1, N1-to-N2, N2-to-N3).

This means that when using small elements it is possible to have contact occur later than expected due to dyna taking the 40% value rather than the element thickness.

This script scans the shells in a model and, once complete, shows which of those are affected by this rule.

Note: if OPTT is set on *PART_CONTACT this rule does not apply. The script ignores parts with OPTT set.

Tested using LS-DYNA R10 and PRIMER v15 (& v14).

The script can be run standalone, without any inputs.