Modal Resonance Simulation - Fusion 360

[Mud]

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This can be helped by taking care not to have the bracing points at integer sub-multiples of the beam length - i.e. avoid 1/2, 1/3, 1/4.

True - and for the same reason our tendency to equi-space supports can be sub-optimal. It does make understanding the dangerous frequencies easier though if all the little sub-sections are similar, and at the extreme you can try to avoid exciting them.

For context, this is big-brain stuff, and unless you enjoy worrying is of diminishing returns past the first few modes.