"Small equation pivot term" error causes analysis to fail
"Small equation pivot term" error causes analysis to fail
(OP)
I've created and applied constraints/loads to a fairly simple car chassis in APDL (created using keypoints/lines and defining a hollow rectangular cross section). The analysis works until I add the final 10ish members to the chassis and then the problem wont solve. Instead I receive the "There is at least 1 small equation solver pivot term. Please check for an insufficiently constrained model" error message.
I don't see how it can be unconstrained if adding in a few extra bars causes it to fail when it was working perfectly before?
Any help would be great, I'll attach my log file too,
thanks!
I don't see how it can be unconstrained if adding in a few extra bars causes it to fail when it was working perfectly before?
Any help would be great, I'll attach my log file too,
thanks!





RE: "Small equation pivot term" error causes analysis to fail
Thanks!
RE: "Small equation pivot term" error causes analysis to fail
They cause problems because they are not attached to the underlying line geometry. You define new lines not attached to the original geometry. After meshing you have a number of unconstrained elements that causes the pivot error. Either redefine your lines using the extra KP:s or use the command "lovlap" to fix it. Do not turn off the small pivot check. If you are having small pivots you are doing something wrong. Turning it off and solving and solving won't make it right.
/petb
RE: "Small equation pivot term" error causes analysis to fail