ForceBeamColumnElement

ForceBeamColumnElement(ndof: int, section: Union[Section, int, str], transformation: Union[GeometricTransformation, int, str], numIntgrPts: int = 5, massDens: float = 0.0, maxIters: int = 10, tol: float = 1e-12, **kwargs)

Bases: Element

Force-based nonlinear beam-column element with distributed plasticity.

This two-node element uses OpenSees' nonlinearBeamColumn formulation to integrate section force-deformation response along the member. It supports 2D models with 3 DOFs per node and 3D models with 6 DOFs per node.

Tcl form

element nonlinearBeamColumn <tag> <iNode> <jNode> <numIntgrPts> <secTag> <transfTag> <-mass massDens> <-iter maxIters tol>

Note

Requires a managed section and geometric transformation with assigned tags before Tcl export.
The -iter parameters control the internal compatibility iteration used by the force-based formulation.

Attributes:

Name	Type	Description
`numIntgrPts`		Number of integration points along the element length.
`massDens`		Mass density per unit length for optional dynamic mass formation.
`maxIters`		Maximum compatibility iterations for the force-based solve.
`tol`		Convergence tolerance for the compatibility iteration.

Example

from femora.core.model import Model
import femora.components.section.beam  # noqa: F401

model = Model()
sec = model.section.beam.elastic(
    user_name="Frame",
    E=29000.0,
    A=18.0,
    Iz=400.0,
    Iy=400.0,
    G=11200.0,
    J=8.0,
)
transf = model.transformation.transformation3d(
    transf_type="Linear",
    vecxz_x=0.0,
    vecxz_y=0.0,
    vecxz_z=1.0,
)
ele = model.element.beam.force(
    ndof=6,
    section=sec,
    transformation=transf,
    numIntgrPts=5,
    maxIters=10,
    tol=1.0e-12,
)
print(ele.tag)

Create a ForceBeamColumnElement with validated dependencies.

Parameters:

Name	Type	Description	Default
`ndof`	`int`	Number of DOFs per node. Must be 3 for 2D or 6 for 3D.	required
`section`	`Union[Section, int, str]`	Managed section object integrated along the member.	required
`transformation`	`Union[GeometricTransformation, int, str]`	Managed geometric transformation defining the local element axis.	required
`numIntgrPts`	`int`	Number of Gauss integration points along the element.	`5`
`massDens`	`float`	Optional mass per unit length for dynamic analyses.	`0.0`
`maxIters`	`int`	Maximum number of internal compatibility iterations.	`10`
`tol`	`float`	Convergence tolerance for compatibility iteration.	`1e-12`
`**kwargs`		Additional element parameters stored on the base element.	`{}`

Raises:

Type	Description
`ValueError`	If `ndof` is unsupported, if the section or transformation is missing, if integration, mass, or iteration inputs are invalid, or if dependencies cannot be resolved.

Methods:

get_mass_per_length

get_mass_per_length() -> float

Return the mass density per unit length.

Returns:

Type	Description
`float`	Mass per unit length assigned to this element.