CircularOGrid2D

CircularOGrid2D(user_name: str, element: Element, region: Optional[RegionBase] = None, *, R: float, r0_ratio: float = 0.4, nt: int = 24, nr: int = 12, merge_tolerance: float = 1e-12)

Bases: MeshPart

Parametric structured 2D circular mesh part with an O-Grid topology.

This mesh part discretizes a circular domain into structured quad elements using a central square grid block surrounded by four transition block grids (O-Grid topology). This provides structured mesh quality without coordinate singularity at the center, ideal for modeling circular piles, shaft sections, or circular domain boundaries.

Note

Exposes a custom node stitching utility (_merge_nodes) to merge coincident coordinates across adjacent grid blocks.
Requires quad elements (such as sspquad or stdquad).

Example

from femora.core.model import Model

model = Model()
mat = model.material.nd.elastic_isotropic(user_name="soil", e_mod=30000.0, nu=0.3, rho=2.0)
ele = model.element.quad.ssp(ndof=2, material=mat)

# Discretize a 2D circular cross-section of radius 5.0
circle = model.meshpart.surface.circular_o_grid(
    user_name="circular_pile_sec",
    element=ele,
    R=5.0,
    r0_ratio=0.4,
    nt=12,
    nr=6,
)
print(circle.tag)

Create a parametric 2D circular O-Grid mesh part.

Parameters:

Name	Type	Description	Default
`user_name`	`str`	Unique user-defined name for this mesh part.	required
`element`	`Element`	Associated Element template used for discretization.	required
`region`	`Optional[RegionBase]`	Physical Region where this mesh part is added.	`None`
`R`	`float`	Radius of the circular domain (must be greater than 0).	required
`r0_ratio`	`float`	Ratio of the inner central square size to the outer radius (must be between 0.1 and 0.9).	`0.4`
`nt`	`int`	Number of element intervals along each block transition edge.	`24`
`nr`	`int`	Number of radial element intervals in the outer ring block.	`12`
`merge_tolerance`	`float`	Distance tolerance used to stitch adjacent block nodes.	`1e-12`

Raises:

Type	Description
`ValueError`	If R <= 0, r0_ratio is outside (0.1, 0.9), nt or nr is less than 1, or if the element type is not a compatible quad element.

Methods:

generate_mesh

generate_mesh() -> pv.UnstructuredGrid

Construct central and ring block coordinates, merge boundary nodes, and compile a PyVista UnstructuredGrid.

Returns:

Type	Description
`UnstructuredGrid`	pv.UnstructuredGrid: The generated circular UnstructuredGrid.