I have a stepped column which I am trying to run a linear buckling analysis on. I used a fixed hinge constraint at one end and at the other end I use a remote load with the displacement option. I dont allow any DOF except rotation and travel along the axix of the column. The constraints look correct, although the analysis never completes saying the matrix is sparse and possibly too few constraints. Can anyone hlep and point me t what I may be doing wrong? Pics attached./ FYI I am trying to get this to run a constant xsec column first and then try my stepped column.

You're model is still allowing rigid body motion then.

Your current remote displacement (based off of the model you posted) has the following definition:

Change it to this and try running it again:

Since you're doing a linear buckling analysis, you don't need any eccentricity or initial perturbation to cause buckling (but also keep in mind the limitations of a linear buckling analysis), so the enforced rotations are not needed.