User is trying to use the probe tool to get reactions at a contact pair between two rigid bodies in workbench, but the answer is always zero. Is this a bug? Is there a workaround?


This is not a bug. It is a documented limitation. The way the probe tool calculates the contact reaction at contact element type 9 (for example) is as follows:

esel,s,real,,9
esel,r,type,,9
nsle
esln
esel,u,ename,,170,175 !*** eliminate contributions of contact elements ***
fsum

In other words, Simulation does not fetch reactions from the contact elements but rather from the non-contact elements who share nodes with the contact elements. For a contact pair between rigid bodies, no non-contact elements passed the (above) test. Hence, results are always zero.

The workaround is to insert a command object to use either FSUM or ETABLE as follows: (refer to contact element documentation for NMISC numbers via ETABLE)


!FSUM approach
!**************
set,,,,,1
ESEL,S,TYPE,,9
nsle,s,1
fsum,,both
!***************


!ETABLE approach
!***************
esel,s,type,,9
nsle,s,1
ETABLE,FZ9,NMISC,45 !contact force in z direction
PRETAB,FZ9
!**************





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