Nonlinear example

This short example runs a repository fixture for the bounded Total-Lagrangian TET4 static route. It demonstrates that the CLI route can run; it is not a qualification claim. The solver intentionally reports a WARNING maturity verdict for this research-profile route.

1. Input

Use the checked-in fixture examples/tet4_geometric_nonlinear_static.json. It defines a small static TET4 problem using the geometric-nonlinear analysis route.

2. Install and solve

From the repository root, install the source checkout into an environment with the project dependencies available, then run the tested CLI entry script:

python -m pip install -e .
python qf_solver.py solve \
  --input examples/tet4_geometric_nonlinear_static.json \
  --output nonlinear-result.json

This checked-in example is also exercised by the CLI integration test. The same installed environment can use qf-solver --help to inspect the installed entry point and other available options.

3. Check the result

The fixture returns status: success, solver.converged: true, and writes the result to nonlinear-result.json. Inspect the nonlinear convergence summary with:

import json
from pathlib import Path

result = json.loads(Path("nonlinear-result.json").read_text(encoding="utf-8"))
solver = result["solver"]
print(solver["converged"], solver["newton_iterations"])
print(solver["final_relative_residual"], solver["scope"])
print(result["run_verdict"], solver["maturity"])

Its overall run verdict is WARNING, because the maturity profile is research under the selected engineering profile. That warning is expected and must not be relabeled as a qualified engineering result.

Inspect the JSON result and solver diagnostics before using any output. A successful nonlinear iteration only establishes that this input completed on this route; it does not validate the physical model or establish accuracy for another mesh, element family, constitutive model, or load path.

4. Applicable limitation

The current geometric campaign covers selected Total-Lagrangian St. Venant–Kirchhoff static serial TET4/HEX8 cases with explicit deformation and formulation bounds. The final audit recorded GO_WITH_LIMITATIONS without a maturity promotion. This example is a convenient smoke test, not a replacement for the 0.2.10 V&V summary or the known limitations.