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"unconstrained degrees of freedom" error on vibrating wire simulation

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I am new to COMSOL and I was trying to imitate 2D vibrating string example from COMSOL in 3D.

I've made a long and thin wire and I am trying to see how it vibrates (like a guitar string)

When I clicked on study I receive "The number of unconstrained degrees of freedom must be at least 3." Error.

I also find the mesh a little odd (screenshot below). Is it because of the mesh is not being correct? I am a little lost.



1 Reply Last Post Nov 9, 2023, 9:58 a.m. EST
Henrik Sönnerlind COMSOL Employee

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Posted: 12 months ago Nov 9, 2023, 9:58 a.m. EST

You are using a physics based mesh. The default in the Wire interface is to use one element per edge. If you then pin the ends, there are no active degrees of freedom in the problem. Switch to a user-controlled mesh instead, and select a suitable number of elements along the edge.

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Henrik Sönnerlind
COMSOL
You are using a physics based mesh. The default in the Wire interface is to use one element per edge. If you then pin the ends, there are no active degrees of freedom in the problem. Switch to a user-controlled mesh instead, and select a suitable number of elements along the edge.

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