| name | jax-modal-analysis |
| description | 3D tetrahedral FEM modal analysis of a membrane STL. Takes a binary STL (mm units) + material properties JSON, repairs surface mesh, generates tetrahedral volume mesh via TetGen, assembles 3D stiffness/mass matrices with jax-fem, solves the generalised eigenvalue problem, and reports eigenfrequencies + mode shapes. Returns artifact JSON with eigenfrequencies_hz, eigenfrequencies_khz, modes_in_range, target_range_pass, and paths to summary PNG and CSV. |
| metadata | {"category":"materials-design","requires":"stl_modal_pipeline, tetgen, pyvista, meshio, trimesh, scipy, jax","conda_env":"jax_fem"} |
JAX 3D Modal Analysis
Full 3D tetrahedral FEM eigenvalue solver for ribbed membrane resonators.
Complements fem-analysis (2D Kirchhoff plate approximation) by accounting for
3D volumetric effects, frame stiffness, and out-of-plane deformation.
Usage
python3 {baseDir}/scripts/jax_modal_analysis.py \
--stl /path/to/membrane.stl \
--material '{"E_Pa":3e9,"nu":0.35,"rho_kg_m3":1500}' \
--num-modes 12 \
--solver-backend jax-iterative \
--stl-length-scale 1e-3 \
--target-freq-min 2000 \
--target-freq-max 8000 \
--output-dir /tmp/jax_modal_results
Arguments
| Flag | Type | Default | Description |
|---|
--stl | path | required | Binary STL file (mm units assumed) |
--material | JSON str | required | {"E_Pa":3e9,"nu":0.35,"rho_kg_m3":1500} |
--num-modes | int | 12 | Number of modes to compute |
--solver-backend | str | jax-iterative | arpack, jax-iterative, or jax-xla |
--stl-length-scale | float | 1e-3 | Scale factor to convert STL units → metres |
--target-freq-min | float | 2000 | Lower bound of target frequency band (Hz) |
--target-freq-max | float | 8000 | Upper bound of target frequency band (Hz) |
--output-dir | path | auto | Directory for all output files |
Output JSON
{
"stl_path": "/path/to/membrane.stl",
"topology": "v1_cricket_fine",
"num_modes_computed": 12,
"eigenfrequencies_hz": [0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 2153.0, 2388.1, ...],
"eigenfrequencies_khz": [0.000, 0.000, 0.000, 0.000, 0.000, 0.000, 2.153, 2.388, ...],
"modes_in_range_hz": [2153.0
Chaining with fem-analysis
fem-analysis and jax-modal-analysis are complementary, not alternatives:
| Skill | Model | Speed | Best for |
|---|
fem-analysis | 2D Kirchhoff plate | ~1 s | Fast screening, flat membranes |
jax-modal-analysis | 3D tetrahedral FEM | 30–120 s | Full 3D validation, ribbed/curved geometries |
Recommended workflow:
- Run
fem-analysis to shortlist candidates (fast 2D pass/fail)
- Run
jax-modal-analysis on shortlisted STLs for full 3D validation
