Symmetry

The node adds an edge (3D), boundary (2D), or point (2D and 3D) condition that defines asymmetry edge, boundary, or point.

Coordinate System Selection

Specify the coordinate system to use for specifying the orientation of the symmetry plane. See the section for Edge Load.

Symmetry

Select an to specify the direction of the normal to the symmetry plane in the selected coordinate system.

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For 2D models, select or for the first or second axis, respectively.

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For 3D models, select , , or for the first, second, or third axis, respectively.

Normal Direction Condition

You can allow a symmetry plane to move along its normal direction. This can be used to model some situations where you want a plane to remain strictly planar but still relax the property of it being fixed.

From the drop-down list, select , , or .

The value gives a standard symmetry condition.

Select to allow the symmetry plane to translate in the normal direction. The displacement is determined by the criterion that there is no resulting reaction force in the normal direction.

Select to prescribe the total reaction force acting on the direction normal to the symmetry plane. Enter the Fn. The force is defined as positive when acting along the outward normal of the symmetry plane. Setting the prescribed force to zero gives the same effect as using .

Select to prescribe the displacement in the direction normal to the symmetry plane. Enter the un0. Setting the prescribed displacement to zero gives the same effect as using .

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Using , , or is only meaningful if the geometry selection corresponds to a single symmetry plane.

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When using or , an extra global degree of freedom is added for determining the displacement in the normal direction. This degree of freedom will have a name of the type <component>.<interface>.<symmetry_tag>.un, for example comp1.beam.sym1.un.

Constraint Settings

To display this section, click the button (

) and select in the dialog box.

In the COMSOL Multiphysics Reference Manual:

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Constraint Reaction Terms

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Weak Constraints

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Constraint Settings


	Symmetry Constraints


	You can activate and deactivate this boundary condition by assigning it to a constraint group. See Load Cases in the Structural Mechanics Modeling chapter.

Location in User Interface

Context Menus

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Physics tab with or selected: