ElasticSection

ElasticSection(user_name: str = 'Unnamed', *, E: float, A: float, Iz: float, Iy: Optional[float] = None, G: Optional[float] = None, J: Optional[float] = None)

Bases: Section

Linear-elastic section defined by explicit geometric and material constants.

This section represents a linear beam-column cross-section. Unlike most other Femora sections, it does not reference a Material object; instead, it takes material moduli (E, G) and geometric properties (A, I, J) directly as constructor arguments.

Tcl form

2D: section Elastic <tag> <E> <A> <Iz>
3D: section Elastic <tag> <E> <A> <Iz> <Iy> <G> <J>

Note

This section is strictly linear. For nonlinear behavior, use FiberSection or UniaxialSection.
When using this section in a 3D model, you must provide all six parameters (E, A, Iz, Iy, G, J). OpenSees usually expects either 3 or 6 values for the Elastic section command.

Tip

Use this section for preliminary modeling or when physical section dimensions are unknown but aggregate properties (like equivalent stiffness) are available.

Example

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

model = Model()
sec_2d = model.section.beam.elastic(
    user_name="Beam2D",
    E=29000.0,
    A=10.0,
    Iz=150.0,
)
sec_3d = model.section.beam.elastic(
    user_name="Column3D",
    E=29000.0,
    A=26.5,
    Iz=999.0,
    Iy=150.0,
    G=11200.0,
    J=2.5,
)
print(sec_3d.tag)

Create an ElasticSection with validated geometric properties.

Parameters:

Name	Type	Description	Default
`user_name`	`str`	User-specified name for the section.	`'Unnamed'`
`E`	`float`	Young's modulus.	required
`A`	`float`	Cross-sectional area.	required
`Iz`	`float`	Second moment of area about the local z-axis.	required
`Iy`	`Optional[float]`	Optional second moment of area about the local y-axis (for 3D).	`None`
`G`	`Optional[float]`	Optional shear modulus (for 3D).	`None`
`J`	`Optional[float]`	Optional torsional constant (for 3D).	`None`

Raises:

Type	Description
`ValueError`	If parameters are not numeric or if essential values (E, A, Iz) are non-positive.

Methods:

get_area

get_area() -> float

Return the cross-sectional area.

Returns:

Type	Description
`float`	Area value.

get_Iy

get_Iy() -> float

Return the second moment of area about the local y-axis.

Returns:

Type	Description
`float`	Iy value, or 0.0 if not defined.

get_Iz

get_Iz() -> float

Return the second moment of area about the local z-axis.

Returns:

Type	Description
`float`	Iz value.

get_J

get_J() -> float

Return the torsional constant.

Returns:

Type	Description
`float`	J value, or 0.0 if not defined.