steel01

steel01

Uniaxial Steel01 hysteretic material wrapping OpenSees Steel01.

Attributes

__all__ module-attribute

__all__ = ['Steel01Material']

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.

Steel01Material

Steel01Material(user_name: str = 'Unnamed', *, Fy: float | None = None, E0: float | None = None, b: float | None = None, a1: float | None = None, a2: float | None = None, a3: float | None = None, a4: float | None = None, **_: Any)

Bases: Material

Bilinear steel plasticity with kinematic hardening and optional isotropic growth.

Implements the OpenSees Steel01 rule for truss, fiber, or spring elements. Yield force is set by Fy with initial elastic stiffness E0 and strain-hardening ratio b. Optional parameters a1 to a4 enable isotropic expansion of the yield surface and must be provided together or omitted entirely.

Tcl form

uniaxialMaterial Steel01 <tag> Fy E0 b [a1 a2 a3 a4]; #

Note

• When all four isotropic parameters exist, they emit after b exactly as OpenSees expects.
• If the isotropic hardening set is omitted, the Tcl command ends after b.
• Stray keyword arguments are ignored to keep factory calls forward compatible.

Attributes:

Name	Type	Description
params		Holds Fy, E0, b, and optional a1 to a4.

Example

from femora.core.model import Model

model = Model()
mat = model.material.uniaxial.steel01(
    user_name="A992",
    Fy=345.0,
    E0=200000.0,
    b=0.01,
)
print(mat.tag)

Validate yield, stiffness, and optional isotropic hardening inputs.

Parameters:

Name	Type	Description	Default
user_name	str	Unique Femora and OpenSees material label surfaced in Tcl.	'Unnamed'
Fy	float | None	Yield strength, strictly positive after coercion.	None
E0	float | None	Initial elastic modulus, strictly positive.	None
b	float | None	Post-yield stiffness ratio E_ep / E0, non-negative.	None
a1	float | None	Isotropic coefficient for compression envelope widening.	None
a2	float | None	Isotropic exponent paired with a1.	None
a3	float | None	Isotropic coefficient for tension envelope widening.	None
a4	float | None	Isotropic exponent paired with a3.	None
**_	Any	Ignored keyword cushioning.	{}

Raises:

Type	Description
ValueError	If Fy, E0, or b is missing.
ValueError	If a numeric parameter cannot be converted correctly.
ValueError	If a validated value falls outside the supported range.
ValueError	If only part of the isotropic hardening set is provided.

Methods:

to_tcl

to_tcl() -> str

Emit Steel01 with optional isotropic arguments.

Returns:

Name	Type	Description
str	str	Tcl text including Fy E0 b and the four optional isotropic
	str	parameters when all were supplied at construction.

Raises:

Type	Description
ValueError	If the material has not been registered with a manager.