FESADev/phases/analysis-model-objects/step4.md

Step 4: material-base-interface

Read First

Read these files before editing:

• /AGENTS.md
• /docs/AGENT_RULES.md
• /docs/ARCHITECTURE.md
• /docs/implementation-plans/analysis-model-objects-implementation-plan.md
• /include/fesa/core/MaterialDefinition.hpp

Task

Add material model base and linear elastic material model object.

Allowed files:

• Create /include/fesa/material/Material.hpp
• Create /include/fesa/material/LinearElasticMaterial.hpp
• Create /src/material/LinearElasticMaterial.cpp
• Create /tests/material/material_base_test.cpp
• Modify /CMakeLists.txt

Required behavior:

• Material has virtual destructor and MaterialId id() const noexcept.
• LinearElasticMaterial derives from Material.
• Stores Young's modulus and Poisson ratio.
• No constitutive matrix or stress update in this phase.

Tests To Write First

Write /tests/material/material_base_test.cpp before production changes:

• Access LinearElasticMaterial through const Material&.
• Verify id, E, and nu.
• Verify deletion through std::unique_ptr<Material>.

Run targeted build and confirm RED.

Acceptance Criteria

Run:

python scripts/validate_workspace.py
ctest --test-dir build/msvc-debug --output-on-failure -C Debug -R model-object

Update step 4 status.

Do Not

• Do not implement constitutive matrices, stress updates, or tangent stiffness.