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Note: This discussion is about an older version of the COMSOL Multiphysics® software. The information provided may be out of date.

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Annular Circular Plate

Posted May 17, 2011, 4:43 p.m. EDT Modeling Tools & Definitions, Parameters, Variables, & Functions, Results & Visualization, Structural Mechanics Version 4.1 1 Reply

Shuodan Chen
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Hello,
I would like to simulate the deflection and stress of an annular circular plate at the inner edge with a 2D axis-symmetric simulation in COMSOL 4.1. The boundary conditions are guided support (there is transverse movement, but no longitudinal nor rotation) on the inner edge and the outer edge is fixed. There is a transverse line load applied at the inner edge.
The issues I'm having are:
1) The boundary constraints in 2D are fixed, roller, and free. How do I define guided support?
2) For edge constraint, the unit is N/m^2. But, I have a line load around the edge, which is total force/circumference. For area, do I multiply the thickness?
3) The maximum displacement according to the colored scale bar (~20mm) and that indicated on the y axis (<1mm) do not match.

I have attached the model file for your reference

Any help to resolve these issues would be much appreciated!

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1 Reply Last Post May 20, 2011, 2:10 p.m. EDT
Nagi Elabbasi Facebook Reality Labs
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Posted: 1 decade ago May 20, 2011, 2:10 p.m. EDT
The problem is that the loads (Force/Length) and boundary conditions (rotations) you want are for structural elements (beam/plate/ shell). However, you are using continuum solid elements. More specific details below:

1. Solid elements have no rotation degrees of freedom. Based on what you described you should restrain the X-displacement at the inner radius. That automatically fixes rotation of that inner face.

2. Yes you should use the thickness of the plate as the other dimension to divide by. That gives you the Force/Length^2 unit.

3. COMSOL is scaling the displacements by a factor of about 0.04. You can change it by expanding the “Surface 1” node of “2D Plot Group 2” and changing the Scale value.

Nagi Elabbasi
Veryst Engineering
The problem is that the loads (Force/Length) and boundary conditions (rotations) you want are for structural elements (beam/plate/ shell). However, you are using continuum solid elements. More specific details below: 1. Solid elements have no rotation degrees of freedom. Based on what you described you should restrain the X-displacement at the inner radius. That automatically fixes rotation of that inner face. 2. Yes you should use the thickness of the plate as the other dimension to divide by. That gives you the Force/Length^2 unit. 3. COMSOL is scaling the displacements by a factor of about 0.04. You can change it by expanding the “Surface 1” node of “2D Plot Group 2” and changing the Scale value. Nagi Elabbasi Veryst Engineering

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