elastic

elastic

Uniaxial linear elastic material used with OpenSees truss, spring, and fiber models.

Attributes

__all__ module-attribute

__all__ = ['ElasticUniaxialMaterial']

Classes

Material

Material(material_type: str, material_name: str, user_name: str)

Bases: ABC

Abstract base class for manager-owned OpenSees material objects.

Material instances do not self-register and do not assign their own tags. A :class:~femora.core.material_manager.MaterialManager owns lifecycle operations, tag assignment, removal, and retagging for a local model context.

Parameters:

Name	Type	Description	Default
material_type	str	OpenSees material category (e.g. 'nDMaterial').	required
material_name	str	Concrete OpenSees material name (e.g. 'ElasticIsotropic').	required
user_name	str	User-specified label for this material instance.	required

Attributes:

Name	Type	Description
tag	Optional[int]	Manager-assigned OpenSees material tag. Remains None until this object is added to a :class:~femora.core.material_manager.MaterialManager.
_owner	object | None	Reference to the owning manager, or None when unmanaged.

Methods:

to_tcl abstractmethod

to_tcl() -> str

Render the OpenSees material definition command as a Tcl string.

updateMaterialStage

updateMaterialStage(state: str) -> str

Return an updateMaterialStage Tcl command, or empty string.

set_parameter

set_parameter(parameter_name: str, new_value: Union[float, int, str, None] = None, element_tags: Optional[List[int]] = None) -> str

Return a setParameter Tcl command, or empty string.

get_param

get_param(key: str) -> Any

Return the value of a stored parameter by key.

ElasticUniaxialMaterial

ElasticUniaxialMaterial(user_name: str = 'Unnamed', *, E: float | None = None, eta: float = 0.0, Eneg: float | None = None, **_: Any)

Bases: Material

One-dimensional elastic stress-strain law with optional asymmetric stiffness.

Suitable for simple bars, trusses, springs, and fiber sections needing a basic uniaxial constitutive rule. The tangent E controls loading stiffness, eta adds optional damping tangent contribution, and Eneg sets an optional distinct compression tangent.

Tcl form

uniaxialMaterial Elastic <tag> E eta Eneg; # user_name

Note

• Manager ownership is required before Tcl export so the OpenSees tag can be inserted after Elastic.
• Eneg defaults to E when omitted.

Attributes:

Name	Type	Description
params	Dict[str, float]	Mapping of emitted E, eta, and Eneg values.

Example

from femora.core.model import Model

model = Model()
mat = model.material.uniaxial.elastic(
    user_name="rebar_truss",
    E=200000.0,
    eta=0.0,
    Eneg=200000.0,
)
print(mat.tag)

Normalize moduli and damping tangent for OpenSees insertion.

Parameters:

Name	Type	Description	Default
user_name	str	Comment key for Tcl plus manager uniqueness constraint.	'Unnamed'
E	float | None	Primary tensile or loading stiffness, strictly positive.	None
eta	float	Supplemental damping tangent, non-negative after coercion.	0.0
Eneg	float | None	Compression-side stiffness. Falls back to E when omitted.	None
**_	Any	Ignored extension keywords.	{}

Raises:

Type	Description
ValueError	If E is missing.
ValueError	If E, eta, or Eneg cannot be converted to numeric values.
ValueError	If E or Eneg is not positive, or if eta is negative.

Methods:

to_tcl

to_tcl() -> str

Return the uniaxialMaterial Elastic command for this instance.

Returns:

Name	Type	Description
str	str	Tcl string with Elastic, the assigned tag, and the stored
	str	E, eta, and Eneg values.

Raises:

Type	Description
ValueError	If the material is unmanaged.