nastran95

NASTRAN-95, the NASA Structural Analysis System, as an executable with a Python wrapper.

Run finite element analyses from Python, with results returned as NumPy arrays.

Features

• Two execution modes: subprocess (robust) or f2py (in-process via fork)
• Automatic output parsing: displacements, stresses, eigenvalues → NumPy arrays
• Full NASTRAN-95 capability: all 13 rigid format solution types
• Simple API: nastran95.run(input_deck) → structured results
• f2py extension: direct Fortran binding with COMMON block access
• Compatible with pyNastran for BDF model generation

Quick Start

import nastran95

# Run a static analysis
result = nastran95.run("inp_clean/d01011a.inp")

if result.completed:
    disp = result.displacements[0]
    print(f"Max displacement: {disp.translations.max():.6e}")

See docs/getting-started.md for full documentation.

Installation

Install both the Fortran executable and the Python wrapper using pre-built wheels:

pip install nastran95

Or, if the wheels are not available for your system, build from source (below).

Building

First, build the NASTRAN-95 Fortran binary in the parent directory (requires gfortran):

cd build
make          # compiles ~1850 Fortran sources (~60 seconds)
cd ..

Then install the Python package:

uv sync

Optionally, build the f2py extension for in-process execution:

cd python
uv run python -m nastran95._fortran.build_ext

Testing

uv run pytest python/tests/ -v

Architecture

python/
├── nastran95/
│   ├── __init__.py          # Public API
│   ├── runner.py            # Subprocess & f2py runners
│   ├── parser.py            # F06 output parser
│   ├── models.py            # Result dataclasses
│   └── _fortran/            # f2py extension
│       ├── build_ext.py     # Build script
│       ├── nastran_entry.f   # Fortran wrapper subroutine
│       ├── exit_override.c   # EXIT/STOP interception via fork()
│       └── _nastran_core*.so # Built extension (after build_ext)
├── tests/
│   ├── test_parser.py       # Output parser tests
│   ├── test_runner.py       # Subprocess runner tests
│   ├── test_f2py.py         # f2py extension tests
│   └── test_pynastran_integration.py  # End-to-end with analytical verification
└── docs/
    ├── getting-started.md   # User guide
    └── api-reference.md     # API documentation