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BC_SYMMETRY

Boundary conditions

*BC_SYMMETRY
plane, csysid${}_1$, csysid${}_2$, csysid${}_3$, $tol$

Parameter definition

Variable
Description
plane
Symmetry planes through the origin
options: 0, X, Y, Z, XY, YZ, ZX, XYZ
csysid${}_1$
ID of coordinate system defining location and orientation (optional) of first symmetry plane. This input is only active if plane=0.
csysid${}_2$
ID of coordinate system defining location and orientation (optional) of second symmetry plane. This input is only active if plane=0.
csysid${}_3$
ID of coordinate system defining location and orientation (optional) of third symmetry plane. This input is only active if plane=0.
$tol$
maximum distance between a node and the symmetry plane for symmetry conditions to be applied

Description

This command defines up to three symmetry planes at $x$, $y$ or $z=0$ or at the origin of specified coordinate systems. When referring to a local coordinate system, the symmetry plane normal is defined as the local x-direction of the coordinate system. The normal direction of the nearest element face is taken as symmetry plane normal in case the local x-direction has not been explicitly defined in the coordinate system command.

Appropriate boundary conditions are automatical applied to nodes located on a symmetry plane. External faces on a symmetry plane are excluded from the contact.

Symmetry conditions are also applied to the boundary of the global particle domain (see PARTICLE_DOMAIN).

Symmetry planes can also be used as rigid frictionless walls, that nodes can not penetrate.

Example

Symmetry plane

The following commands apply symmetry boundary conditions on a surface. A point on the symmetry plane is defined through a local coordinate system with ID = 20. The normal of the nearest element face is used as symmetry plane normal.

*PARAMETER x0 = 0.2 y0 = 0.0 z0 = 0.1 *BC_SYMMETRY 0, 20 *COORDINATE_SYSTEM_FIXED 20, [%x0], [%y0], [%z0]
Symmetry plane
Symmetry plane