I am trying to do a harmonic sim on a 2d mesh of aluminum sheet metal and the results are showing the first six modes being less than .0002 Hz. I meshed the assembly by doing a midplane surface between all of the components, and then used edge stitching to attach the pieces together. I also used Mesh Mating with the non-coincident glueing option for any pieces that required face to face stitching (which is not a thing).
I ran this same mesh with a linear buckling sim on the 105 Linear Buckling solver and it worked fine and gave accurate results, although that sim contained boundary conditions. I know that in NX 10, to do harmonic sims, our team would use the 103 Real Eigenvalues solver and got accurate results but there was a checkbox for inertial relief, which allowed us to use no boundary conditions. My question is, how should I be setting this up, because the current results I am getting do not seem to be too trustworthy, based on the first 6 modes being a little janky.
Here is a picture of the first mode and the chain of modes: