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Modeling cloth

Posted 21 janv. 2019, 10:37 UTC−5 Structural & Acoustics 3 Replies

Ke Wu
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Hi there,

I have a problem modelling a piece of cloth in COMSOL. The key feature of cloth is that it has no bending stiffness or out-of-plane shear stiffness. Could you tell me how to set the right material for the cloth?

Thanks so much, Ke Wu

3 Replies Last Post 25 janv. 2019, 02:17 UTC−5
Henrik Sönnerlind COMSOL Employee

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Posted: 5 years ago 22 janv. 2019, 03:43 UTC−5

Hi,

For cloth (and other thin layers with negligible bending stiffness), you need to use the Membrane interface.

However, be warned: It is difficult to obtain convergence in such models, since in real life wrinkles tend to develop unless the two in-plane principal stresses are positive everywhere. A geometrically nonlinear analysis with some initial stress which induces tension in the first iterations is a minimum requirement.

Regards,
Henrik

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Henrik Sönnerlind
COMSOL
Hi, For cloth (and other thin layers with negligible bending stiffness), you need to use the Membrane interface. However, be warned: It is difficult to obtain convergence in such models, since in real life wrinkles tend to develop unless the two in-plane principal stresses are positive everywhere. A geometrically nonlinear analysis with some initial stress which induces tension in the first iterations is a minimum requirement. Regards, Henrik
Ke Wu
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Posted: 5 years ago 23 janv. 2019, 06:49 UTC−5

Thank you so much！

Can I use shell interface instead considering membrane is so hard to converge？

What I am modeling is an airtight cloth with inner pressure inside.

The idea is to set a prescribed distance at its center to get its corresponding reaction force.

I've attached 2 screen shots below.

Thanks in advance, Ke Wu

Thank you so much！ Can I use shell interface instead considering membrane is so hard to converge？ What I am modeling is an airtight cloth with inner pressure inside. The idea is to set a prescribed distance at its center to get its corresponding reaction force. I've attached 2 screen shots below. Thanks in advance, Ke Wu

Attachments:

Henrik Sönnerlind COMSOL Employee

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Posted: 5 years ago 25 janv. 2019, 02:17 UTC−5

Hi,

You can use the Shell interface. The reason not to do that is that as the bending stiffness gets smaller, the numerics gets more and more ill-conditioned. But as long as the solver does not throw warnings or errors at you, a shell solution will work. Due to the bending stiffness there will be no tendency to wrinkling.

Regards,
Henrik

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Henrik Sönnerlind
COMSOL
Hi, You can use the Shell interface. The reason not to do that is that as the bending stiffness gets smaller, the numerics gets more and more ill-conditioned. But as long as the solver does not throw warnings or errors at you, a shell solution will work. Due to the bending stiffness there will be no tendency to wrinkling. Regards, Henrik

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