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Karman plate theory

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Hello all,

Does Comsol support von Karman plate theory? I am trying to solve a problem with large deflections. I read manual and it seems it only supports Kirchhoff-love plate theory.

Thank you ,
Hossein

5 Replies Last Post 03.06.2016, 16:55 GMT-4
Henrik Sönnerlind COMSOL Employee

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Posted: 10 years ago 27.08.2014, 16:43 GMT-4
Hi,

The von Kármán plate theory is a geometrically nonlinear theory for thin plates under moderately large deformations.

The plate elements in COMSOL Multiphysics are based on Mindlin (thick plate) theory, but will converge to thin plate theory when the thickness is small. The displacements and rotations can be arbitrarily large. They do also allow in-plane loads, which cause stiffening.

You should thus be able to solve problems which are within the regime covered by von Kármán plate theory with the plate elements in COMSOL.

Regards,
Henrik
Hi, The von Kármán plate theory is a geometrically nonlinear theory for thin plates under moderately large deformations. The plate elements in COMSOL Multiphysics are based on Mindlin (thick plate) theory, but will converge to thin plate theory when the thickness is small. The displacements and rotations can be arbitrarily large. They do also allow in-plane loads, which cause stiffening. You should thus be able to solve problems which are within the regime covered by von Kármán plate theory with the plate elements in COMSOL. Regards, Henrik

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Posted: 10 years ago 27.08.2014, 16:56 GMT-4
Thank you Henrik.
Thank you Henrik.

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Posted: 9 years ago 21.05.2015, 22:59 GMT-4
Dear Henrik:
Thanks for your explanation!
I am also doing research related to von Kármán plate theory, I got an analytical solution of
circular plate, and the results match well with COMSOL result when I apply uniform pressure
to plate and the plate deform freely.

But when I underlaid another plate to constrint the deflection greater than a certain value,
the analytical result did not match well with that of COMSOL.
(As in the attachment, the annular part is the top view of the plate in this situation.)

Would you please explain how to add boundary condition or other parameters when
solving this problem?

Thanks!

Wang Jiujiang





Hi,

The von Kármán plate theory is a geometrically nonlinear theory for thin plates under moderately large deformations.

The plate elements in COMSOL Multiphysics are based on Mindlin (thick plate) theory, but will converge to thin plate theory when the thickness is small. The displacements and rotations can be arbitrarily large. They do also allow in-plane loads, which cause stiffening.

You should thus be able to solve problems which are within the regime covered by von Kármán plate theory with the plate elements in COMSOL.

Regards,
Henrik


Dear Henrik: Thanks for your explanation! I am also doing research related to von Kármán plate theory, I got an analytical solution of circular plate, and the results match well with COMSOL result when I apply uniform pressure to plate and the plate deform freely. But when I underlaid another plate to constrint the deflection greater than a certain value, the analytical result did not match well with that of COMSOL. (As in the attachment, the annular part is the top view of the plate in this situation.) Would you please explain how to add boundary condition or other parameters when solving this problem? Thanks! Wang Jiujiang [QUOTE] Hi, The von Kármán plate theory is a geometrically nonlinear theory for thin plates under moderately large deformations. The plate elements in COMSOL Multiphysics are based on Mindlin (thick plate) theory, but will converge to thin plate theory when the thickness is small. The displacements and rotations can be arbitrarily large. They do also allow in-plane loads, which cause stiffening. You should thus be able to solve problems which are within the regime covered by von Kármán plate theory with the plate elements in COMSOL. Regards, Henrik [/QUOTE]


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Posted: 8 years ago 03.06.2016, 16:42 GMT-4
Hi, I have a problem on my thin plate bending simulation.
I do a simulation on thin plate big bending deformation, use 1/4 axial symmetry 3-D model, displacement(5mm*0.45) are loaded in free end ,the size of the thin plate is 5mm*4mm*0.1mm, the results shows in the width direction there are big stress near the axial symmetry boundary, it seems there in no slide in width direction in the axial symmetry boundary. Could you help me, what is wrong with my model and how could I eliminate the stress in width direction (at least much smaller than that in longitudinal direction )
Attached is my model.
Thanks!
Hi, I have a problem on my thin plate bending simulation. I do a simulation on thin plate big bending deformation, use 1/4 axial symmetry 3-D model, displacement(5mm*0.45) are loaded in free end ,the size of the thin plate is 5mm*4mm*0.1mm, the results shows in the width direction there are big stress near the axial symmetry boundary, it seems there in no slide in width direction in the axial symmetry boundary. Could you help me, what is wrong with my model and how could I eliminate the stress in width direction (at least much smaller than that in longitudinal direction ) Attached is my model. Thanks!

Jeff Hiller COMSOL Employee

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Posted: 8 years ago 03.06.2016, 16:55 GMT-4
Your posting suggests you may have over-constrained the structure compared to what you intended to do. Can you please post the mph file and a sketch of what you intended to do?
Jeff
Your posting suggests you may have over-constrained the structure compared to what you intended to do. Can you please post the mph file and a sketch of what you intended to do? Jeff

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