add euler beam uel phase

2026-06-11 11:08:44 +09:00
parent 986cc9888e
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+# Step 2: formulation
+
+## Read First
+
+- `/AGENTS.md`
+- `/docs/ABAQUS_SUBROUTINE_AGENT_DESIGN.md`
+- `/docs/ARCHITECTURE.md`
+- `/docs/ADR.md`
+- `/.codex/skills/abaqus-subroutine-formulation/SKILL.md`
+- `/docs/requirements/uel-3d-euler-beam.md`
+- `/docs/research/uel-3d-euler-beam-research.md`
+- `/docs/formulations/README.md`
+
+## Task
+
+Create `/docs/formulations/uel-3d-euler-beam.md`.
+
+Define the implementable finite element formulation for the first 3D Euler-Bernoulli beam `UEL` scope. Include:
+
+- Element topology, node ordering, local axes, and DOF ordering.
+- Required material and section parameters.
+- Local 12x12 stiffness matrix terms for axial, torsion, bending about local 2, and bending about local 3.
+- Transformation matrix from local to global coordinates and orientation-vector validation.
+- Internal force/residual relation for static small-displacement analysis.
+- `AMATRX` and `RHS` contribution rules by `LFLAGS` for the supported procedure subset.
+- Numerical tolerances for zero length, near-parallel orientation vector, non-positive section/material properties, and matrix symmetry.
+- State variable policy. If no persistent state is needed, state that `SVARS` is not used except optional diagnostics approved by requirements.
+- Output recovery quantities that external CSV validation should compare.
+
+Do not define the full Abaqus ABI signature here unless needed to express formulation responsibilities; the interface step owns the ABI contract.
+
+Do not create or modify Fortran source, tests, reference artifacts, or implementation plans in this step.
+
+## Tests To Write First
+
+- None. This is a formulation artifact step.
+
+## Acceptance Criteria
+
+```bash
+python -m unittest discover -s scripts -p "test_*.py"
+python scripts/validate_reference_artifacts.py
+python scripts/validate_workspace.py
+```
+
+The step is complete only when `/docs/formulations/uel-3d-euler-beam.md` has enough matrix, residual, and transformation detail for a later implementation step to code without inventing physics.
+
+## Validation Notes
+
+- Keep solver-result validation as externally generated ODB-extracted CSV evidence.
+- Update `/phases/uel-3d-euler-beam/index.json` step 2 with `completed`, `error`, or `blocked` and a concrete summary or reason.
+
+## Forbidden
+
+- Do not add JavaScript/TypeScript/npm fallback.
+- Do not run Abaqus analyses from this project.
+- Do not generate reference CSVs.
+- Do not create Fortran production source.
+- Do not break existing tests.