Sound_Spinning
i have been fiddling around with your sample problem
and some of my owns
and thinking over the more general mater
in your sample problem:
master and slave surfaces are lying in the same plane
and with the specific loading case
DISTANCE_MAX should be set at 0+epsilon (exactly 0 seems to work)
had the two surfaces been in two parallel planes with a normal distance delta
then DISTANCE_MAX should be set at delta+epsilon
as you master completely the geometry and meshing of the assembly you should master as well DISTANCE_MAX!
but it may be possible to imagine a problem where the designer or engineer wants to extend the area of influence of slave onto master (or master onto slave)
he will then change DISTANCE_MAX to a suitable value
taking that into account and considering what i can see as the general philosophy of code_aster
which is "the code does make a choice where the user should make it"
my opinion is that setting an automated value to DISTANCE_MAX would not be a good idea
on my investigations i however discovered an unexpected behavior of LIAISON_MAIL with a somewhat different geometry
i have to work on that to find out the way trough
