Cauchy Continuum Model

sgio.model.solid.CauchyContinuumModel is the solid material model: three displacements (\(u_1\), \(u_2\), \(u_3\)) and six strain components (\(\varepsilon_{11}\), \(\varepsilon_{22}\), \(\varepsilon_{33}\), \(\varepsilon_{23}\), \(\varepsilon_{13}\), \(\varepsilon_{12}\)).

It supports isotropic, orthotropic, and fully anisotropic materials, validates on construction and assignment, and serializes through Pydantic’s model_dump() / model_dump_json().

Create a Material

The constructor takes engineering constants as keyword arguments; validators enforce units and admissible ranges.

from sgio.model.solid import CauchyContinuumModel

carbon_ud = CauchyContinuumModel(
    name='UD Carbon/Epoxy',
    isotropy=1,
    density=1570.0,
    e1=138e9, e2=9e9, e3=9e9,
    g12=5.2e9, g13=5.2e9, g23=3.5e9,
    nu12=0.32, nu13=0.32, nu23=0.45,
    cte=[2.5e-6, 2.5e-6, 2.4e-5, 0.0, 0.0, 0.0],
)

Query and Update

Typed setters and queries are the supported path:

from sgio.model import ElasticInputType, MatrixKind, TensorComponent

carbon_ud.set_isotropy('orthotropic')
carbon_ud.set_elastic([210e9, 0.29], input_type=ElasticInputType.ISOTROPIC)

c11 = carbon_ud.get_matrix_component(MatrixKind.STIFFNESS, TensorComponent(1, 1))

set_strength_constants() sets the strength values, and get_thermal_expansion() reads the CTE components.

Load from JSON

Because the model is a Pydantic model, a JSON document maps onto it directly — whether it comes from a file, a database, or an API response:

import json
from pathlib import Path

material = CauchyContinuumModel(**json.loads(Path('material.json').read_text()))

See Load Cauchy Continuum Material from JSON.