Nondeforming Boundary
Use the Nondeforming Boundary multiphysics coupling to define boundaries that do not undergo deformation in the normal direction.
A Nondeforming Boundary can be applied to external boundaries of an electrolyte and is typically used to specify an insulator, a nondissolving/depositing electrode surface or a symmetry boundary in a problem.
The node, available as a multiphysics coupling node, is only applicable when both the Electrochemistry interface (Primary/Secondary/Tertiary Current Distribution or Lithium-Ion Battery or Battery with Binary Electrolyte) and a Deformed Geometry node are added to a component.
Zero normal displacement is implemented using pointwise constraints, which may be more numerically stable, but should typically only be used for planar boundaries since the boundary is effectively fixed in the tangential direction if the curvature of the boundary is nonzero.
As a rule of thumb: use Zero normal displacement for planar boundaries and Zero normal velocity for curved boundaries.
For 3D components, and when Zero normal displacement is selected, the deformation may be further stabilized by enabling the Allow deformation along specified line only. The specified line must be parallel to the boundary in the nondeformed geometry.
See also the Deforming Electrode Surface node.