User Area > Advice
How do I define support conditions for axisymmetric elements?
All nodes of axisymmetric elements lying on the axis
of symmetry must be restrained to prevent any radial displacement
across the symmetry axis. To displace in such a way (even
by a small amount) would violate conservation of energy
laws. If support conditions are not imposed, such violation
can go undetected or can produce pivot and/or Jacobian warnings
in the output file – but either way, the results could
be significantly inaccurate. Axial support is additionally
required to prevent axial rigid body motion
Nodes not lying on the symmetry axis are
normally required to displace without restraints from supports.
The radial support in this case comes from the hoop stiffness
of the element formulation. The only support required is
axial in this case
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