carputils.mesh.Ring

class carputils.mesh.Ring(radius, thickness=None, height=None, div_transmural=1, div_circum=None, div_height=1, *args, **kwargs)

Generate a mesh of a ring/cylindrical shell.

This class describes a tissue ring, and generates the described mesh. For example, to define a ring with a 5mm internal radius:

>>> geom = Ring(5)

By default, the thickness of the ring is 1/5 of the radius, and the height is the same as the thickness. These can be controlled exactly with the corresponding paramters:

>>> geom = Ring(5, thickness=0.5, height=0.7)

Discretisation of the ring is done into hexahedra, with one hex across both the thickness and height. The circumferential discretisation is chosen to ensure as regular aspect hexahedra as possible. If a tetrahedral mesh is generated, these hexahedra are further subdivided into tets. Discretisation can be controlled with the division div_ parameters:

>>> geom = Ring(5, 2, 0.7, div_transmural=3)

The ring’s fibre directions are, by default, oriented in the circumferential direction. To control the fibre direction, pass a function as the fibre_rule argument that itself takes a normalised transmural distance and returns a helix angle in radians:

>>> rule = lambda t: (1 - t)/2
>>> geom = Ring(5, 2, 0.7, fibre_rule=rule)

carputils.mesh.ring.linear_fibre_rule() provides a convenient method to generate such rules. For example, to generate a +60/-60 degrees linear fibre rule:

>>> rule = linear_fibre_rule(60, -60)
>>> geom = Ring(5, 2, 7, fibre_rule=rule)

To generate the actual mesh, use the generate_carp() and generate_vtk() methods.

Args:

radius : float

Inner radius of the ring, in mm

thickness : float, optional

Radial thickness of the ring, in mm, defaults to 1/5 inner radius

height : float, optional

Height of the ring, in mm, by default set to a size to regularise aspect ratio

div_transmural : int, optional

Number of elements across the radial thickness, defaults to 1

div_circum : int, optional

Number of elements around the full circle of the ring, defaults to a number regularising the hexahedron aspects

div_height : int, optional

Number of elements across the height of the ring, defaults to 1

tetrahedrise : bool, optional

True to subdivide the mesh into tetrahedra

fibre_rule : callable, optional

Function describing the transmural variation of fibre angle, takes a single normalised transmural distance on [0,1] and returns a helix angle in radians, defaults to circumferentially oriented fibres

cavity_volume()

Calculate the volume of the cavity analytically.

The actual volume may be less due to discretisation effects.

Returns:

float

The cavity volume

classmethod with_resolution(radius, resolution, height=None, wallthickness=None, **kwargs)

Simplified interface to generate ring with target resolution.

Args:

radius : float

Inner radius of ellipsoid cavity

resolution : float

Target mesh edge length

height : float, optional

Vertical thickness of ring (default: radius/10)

wallthickness : float, optional

Thickness of ellipsoid wall (default: radius/5)