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Simple plate bending 3D - local bending moment

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Hi, I have modelled a plate in 3D with a pressure load and some boundary conditions. I want to find the bending moment in the global X and Y directions. When I go to evaluate the results I find that there are 6 quanitites from which I can choose from. My question is what does the following corresponds to in terms of the global coordinate system:

Local bending moment, 11 component Local bending moment, 12 component Local bending moment, 13 component

and so on?

I have also noticed that it says local bending moment, but the unit is N, how come? As you can tell I am a beginner with using COMSOL.


3 Replies Last Post Sep 9, 2020, 2:24 a.m. EDT
Henrik Sönnerlind COMSOL Employee

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Posted: 4 years ago Sep 1, 2020, 2:13 a.m. EDT
Updated: 4 years ago Sep 1, 2020, 2:13 a.m. EDT

As long as you have not changed to a local coordinate system explicitly (in the Linear Elastic Material) the local directions will coincide with the global directions.

The unit for a plate bending moment is Nm/m, or equivalently N.

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Henrik Sönnerlind
COMSOL
As long as you have not changed to a local coordinate system explicitly (in the Linear Elastic Material) the local directions will coincide with the global directions. The unit for a plate bending moment is Nm/m, or equivalently N.

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Posted: 4 years ago Sep 8, 2020, 5:25 a.m. EDT

I have not changed any coordinate system. So Local beding component 11 correspond to the bending around the X-axis or the y-axis?

I have not changed any coordinate system. So Local beding component 11 correspond to the bending around the X-axis or the y-axis?

Henrik Sönnerlind COMSOL Employee

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Posted: 4 years ago Sep 9, 2020, 2:24 a.m. EDT

The indices correspond to the stress component that causes this moment (or other section force). Thus, Ml11 will be bending around the Y-axis, while Nl11 will be a membrane force (which is zero in a linear plate bending problem) in the X-direction.

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Henrik Sönnerlind
COMSOL
The indices correspond to the stress component that causes this moment (or other section force). Thus, Ml11 will be bending around the Y-axis, while Nl11 will be a membrane force (which is zero in a linear plate bending problem) in the X-direction.

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