The Symmetry node adds an edge or boundary condition that defines a symmetry edge or boundary.
This setting is used in conjunction with a Local edge system and
Shell Local System. If symmetry is prescribed for an edge which is shared between boundaries, the edge system can be ambiguous. Select the boundary which should define the edge system. The default is
Use face with lowest number.
If another coordinate system than the Local edge system is used, select an
Axis to use as symmetry plane normal. Select
1,
2, or
3 for the first, second, or third axis, respectively.
The value No displacement gives a standard symmetry condition.
Select Free Displacement 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 Prescribed force to prescribe the total reaction force acting on the direction normal to the symmetry plane. Enter the
Normal force 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
Free Displacement.
Select Prescribed displacement to prescribe the displacement in the direction normal to the symmetry plane. Enter the
Normal displacement un0. Setting the prescribed displacement to zero gives the same effect as using
No displacement.
) and select Advanced Physics Options in the Show More Options dialog box. 
