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Prescribed Displacement vs Boundary Load

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Hi all,

I'm new to comsol and trying to figure something out. I'm making a helix geometry of some thickness, and trying to stretch it along the long axis. When I use a prescribed displacement, the helix elongates, only in the long (z) axis, as I like. However, I would like to instead use a force (of known amount) to stretch the helix. When I apply a boundary load to the end boundary of the helix, the displacement now goes out of plane, not just in the z direction. Does anyone know why this is happening/how to keep the extension only in the z direction?


1 Reply Last Post 09.03.2020, 11:38 GMT-4
Henrik Sönnerlind COMSOL Employee

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Posted: 5 years ago 09.03.2020, 11:38 GMT-4

If the force resultant is not at the center of the helix, it will bend, since you implicitly apply a moment. With a prescribed displacement, you force it not to bend.

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Henrik Sönnerlind
COMSOL
If the force resultant is not at the center of the helix, it will bend, since you implicitly apply a moment. With a prescribed displacement, you force it not to bend.

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