I have assemblies with contact in which I have defined local
contact conditions for all of the faces that interact or are
Almost by accident I found that the models mesh differently (and
run differently) depending on whether the Global Contact Condition
is set to Free vs. Bonded or No Penetration and that they also mesh
differently whether I mesh in SW2008 SP3.0 on X32 or X64.
I care because in some of my more complex models this is enough
difference to make the model either run or not run at all (i.e. it
sits at the first contact iteration forever trying to determine
number of contact points).
To test this I loaded one of the tutorial models "Nl_Pipe_Holder"
and meshed it both ways.
In SW2008 SP3.0 on X64, with Global set to Bonded and a default
element size/tolerance of .12"/.006" I got 3619 elements.
With Global set to Free I got 3594 elements.
To make it worse, the model meshes differently when run an an XP32
machine where Bonded results in 3595 elements and Free gives 3597.
(I've already reported this problem earlier and it was assigned SPR
From the attached screen dumps you can see that the contact surface
of the "pipe" has meshed differently at the spot the two parts
initially touch, even though a Local Contact Condition already
specifies these faces as No Penetration.
According to the documentation the local conditions should override
global conditions, so why does the global setting make a difference
When you run the analysis it is obvious that the No Penetration
condition has won out as the parts can slide over each other.