When you run a model analysis, you get the error:
Set the mesh size smaller.
Reason: the number of eigenfrequencies (and eigenmodes) that can be calculated for a structure depends on the degrees of freedom. For example: a column has a fixed support at the bottom. And has 8 divisions in the mesh.
- Without additional boundary conditions, each meshnode has 6 degrees of freedom. Thus you’ll be able to calculate 8 x 6 = 48 eigenfrequencies. From the moment you ask 49 eigenfrequencies, you’ll get the error above.
- If you prevent for example the displacement in the Z-direction and the rotation around the X-axis along the column, the model has 4 degrees of freedom. You’ll be able to calculate 8 x 4 = 32 eigenfrequencies.