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Posted Nov 21, 2021, 8:20 a.m. EST 5 Replies

Carl Xu
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question closed

5 Replies Last Post Dec 20, 2021, 3:52 a.m. EST
Henrik Sönnerlind COMSOL Employee

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Posted: 3 years ago Nov 22, 2021, 3:53 a.m. EST
Updated: 3 years ago Nov 22, 2021, 3:53 a.m. EST

In the weak contribution, one term is . This means that must adapt so that the thickness direction stress is zero (in the weak sense).

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Henrik Sönnerlind
COMSOL
In the weak contribution, one term is \sigma_z \cdot \mathrm{test}(\epsilon_z) . This means that \epsilon_z must adapt so that the thickness direction stress is zero (in the weak sense).
Carl Xu
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Posted: 3 years ago Nov 23, 2021, 5:21 a.m. EST

That's what I expected but I never saw this in equation view in any version higher than 5, why?

That's what I expected but I never saw this in equation view in any version higher than 5, why?
Carl Xu
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Posted: 3 years ago Dec 8, 2021, 3:13 a.m. EST

When plane stress is chosen, there seems to be no constraint on the z stress in its strong or weak form, why?

When plane stress is chosen, there seems to be no constraint on the z stress in its strong or weak form, why?
Henrik Sönnerlind COMSOL Employee

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Posted: 3 years ago Dec 9, 2021, 8:35 a.m. EST

The weak equation reads:

(-solid.Sl11*test(solid.el11)-2*solid.Sl12*test(solid.el12)-2*solid.Sl13*test(solid.el13)-solid.Sl22*test(solid.el22)-2*solid.Sl23*test(solid.el23)-solid.Sl33*test(solid.el33))*solid.d

Now, if you look in Equation View, you will find that solid.el33 is equal to the auxiliary degree of freedom wZ, representing the strain in the transverse direction. This DOF will then be adjusted so that the transverse stress solid.Sl33 is forced to be zero (in a weak sense).

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Henrik Sönnerlind
COMSOL
The weak equation reads: (-solid.Sl11\*test(solid.el11)-2\*solid.Sl12\*test(solid.el12)-2\*solid.Sl13\*test(solid.el13)-solid.Sl22\*test(solid.el22)-2\*solid.Sl23\*test(solid.el23)-solid.Sl33\*test(solid.el33))\*solid.d Now, if you look in *Equation View*, you will find that solid.el33 is equal to the auxiliary degree of freedom wZ, representing the strain in the transverse direction. This DOF will then be adjusted so that the transverse stress solid.Sl33 is forced to be zero (in a weak sense).
Carl Xu
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Posted: 3 years ago Dec 20, 2021, 3:52 a.m. EST
Updated: 3 years ago Dec 20, 2021, 3:52 a.m. EST

Thank you very much Dr Sönnerlind.

Thank you very much Dr Sönnerlind.

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