Error: Index was outside the bounds of the array at Dew.Math.TMtxVec.get_DefaultArray(…)

When you run a model analysis, you get the error:

Solution

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.