<HexahedronElasticForce />¶

Doxygen: SofaCaribou::forcefield::HexahedronElasticForce

Implementation of a corotational linear elasticity forcefield for hexahedral topologies.

Requires a mechanical object. Requires a topology container.

Attribute	Format	Default	Description
printLog	bool	false	Output informative messages at the initialization and during the simulation.
youngModulus	float	1000	Young’s modulus of the material
poissonRatio	float	0.3	Poisson’s ratio of the material
corotated	bool	true	Whether or not to use corotated elements for the strain computation. The rotation is viewed as constant on the element and is extracted at its center point.
topology_container	path		Path to a topology container (or path to a mesh) that contains the hexahedral elements.
integration_method	option	Regular	Integration method used to integrate the stiffness matrix. Regular Regular 8 points gauss integration (default). OnePointGauss One gauss point integration at the center of the hexahedron

Quick example¶

XML

<Node>
    <RegularGridTopology name="grid" min="-7.5 -7.5 0" max="7.5 7.5 80" n="9 9 21" />
    <MechanicalObject src="@grid" />
    <HexahedronSetTopologyContainer name="topology" src="@grid" />
    <HexahedronElasticForce topology_container="@topology" youngModulus="3000" poissonRatio="0.49" corotated="1" printLog="1" />
</Node>

Python

node.addObject("RegularGridTopology", name="grid", min=[-7.5, -7.5, 0], max=[7.5, 7.5, 80], n=[9, 9, 21])
node.addObject("MechanicalObject", src="@grid")
node.addObject("HexahedronSetTopologyContainer", name="topology", src="@grid")
node.addObject("HexahedronElasticForce", topology_container="@topology", youngModulus=3000, poissonRatio=0.49, corotated=True, printLog=True)

Available python bindings¶

class HexahedronElasticForce¶

class GaussNode¶

Members

weight : Gauss node’s weight. numpy.double
jacobian_determinant : Gauss node’s Jacobian determinant. numpy.double
dN_dx : Gauss node’s shape derivatives w.r.t. the current position vector. numpy.ndarray
F : Gauss node’s strain tensor. numpy.ndarray

gauss_nodes_of(hexahedron_id)¶

Parameters: hexahedron_id (int) – Index of the hexahedron in the topology container.
Returns: Reference to the list of Gauss nodes of the element.
Return type: list [GaussNode]
Note: No copy involved.

stiffness_matrix_of(hexahedron_id)¶

Parameters: hexahedron_id (int) – Index of the hexahedron in the topology container.
Returns: Reference to the elemental 24x24 tangent stiffness matrix
Return type: numpy.ndarray
Note: No copy involved.

Get the elemental 24x24 tangent stiffness matrix of the given hexahedron.

K()¶

Returns: Reference to the forcefield tangent stiffness matrix
Return type: scipy.sparse.csc_matrix
Note: No copy involved.

Get the tangent stiffness matrix of the force field as a compressed sparse column major matrix.

cond()¶

Returns: Condition number of the forcefield’s tangent stiffness matrix
Return type: numpy.double

eigenvalues()¶

Returns: Reference to the eigen values of the forcefield’s tangent stiffness matrix.
Return type: list[numpy.double]