add-material-preset

name

add-material-preset

description

Add a new composite material system to the MATERIALS preset registry. Use when the user says things like "add T1100/epoxy as a preset", "register a new material", or "add an HM63 carbon system" — anything that needs a new keyed entry under porosity_fe/materials.py:MATERIALS so it shows up in the Streamlit sidebar dropdown and is selectable by name from compare_configurations / build_empirical_pipeline.

Add a material preset

A preset is a MaterialProperties(...) value stored under a string key in the MATERIALS dict in porosity_fe/materials.py. The Streamlit sidebar reads list(MATERIALS.keys()) (app.py:479) and the analysis pipeline resolves names via MATERIALS[cfg["material_name"]] (app.py:120-125), so a single registry entry covers both the UI dropdown and the CLI.

Required information from the user

Get all of these before writing — MaterialProperties has no defaults for the engineering constants, so a missing field is a hard error:

• Identity: short snake_case key (e.g. T1100_epoxy), fiber name, matrix resin name, and a citation for the lamina properties (Daniel & Ishai, WWFE, manufacturer data sheet, etc.).
• Stiffness (MPa): E11, E22, E33, G12, G13, G23, nu12, nu13, nu23.
• Strength (MPa): sigma_1c, sigma_1t, sigma_2t, sigma_2c, tau_12, tau_ilss.
• Geometry (mm / count): t_ply, n_plies.
• Constituents (used by the FE Eshelby/Mori-Tanaka micromechanics path — populate even if the user only plans to run the empirical solver, both paths read from the same dataclass): matrix_modulus, matrix_poisson, fiber_modulus, fiber_volume_fraction.

If the user only has a partial spec, ask for the missing fields before editing — don't invent values.

Steps

1. Sanity-check the inputs. Confirm:

   • E11 > E22 (fiber direction stiffer than transverse).
   • nu12 < 0.5 and the orthotropic compliance is positive-definite (rough check: 1 - nu12*nu21 - nu23*nu32 - nu13*nu31 - 2*nu21*nu32*nu13 > 0, using nu21 = nu12 * E22 / E11 etc.).
   • fiber_volume_fraction in [0.3, 0.8] (the validation-dataset schema enforces this bound for a reason — quote that to the user if their Vf is outside it).

2. Edit porosity_fe/materials.py. Add the entry to the MATERIALS dict near line 495, keeping the existing style (multiline block with the same field ordering as the surrounding presets). Include a one-line citation comment above the entry pointing at the source (e.g. # AS4/3501-6 — Soden, Hinton & Kaddour, WWFE-I, CST 1998).

3. Wire it into the existence-check test. In tests/test_materials.py, the TestMATERIALS block (around line 31) asserts each preset key is in MATERIALS and pulls representative fields. Add an analogous assertion for the new key so a future accidental deletion fails CI.

4. Run the gate locally:

   python -m pytest tests/test_materials.py -v
   ruff check porosity_fe/materials.py
   mypy porosity_fe/materials.py
   

   (Use python -m pytest rather than bare pytest — the web-container pytest is uv-isolated and can't see the project deps; see CLAUDE.md.)

5. Don't touch app.py, compare_configurations, or the validation datasets. The Streamlit dropdown picks up new keys automatically from list(MATERIALS.keys()); compare_configurations resolves the name through the same dict; validation datasets describe what was experimentally tested and aren't tied to the preset registry.

What this skill does NOT cover

• Calibrating empirical alpha/n/beta for the new material. Those live on EmpiricalSolver (not on MaterialProperties) and need coupon data to fit. See README "Calibrating alpha / n for a custom material". If the user wants the new preset to ship with non-QI coefficients, surface that as a separate follow-up.
• Adding a validation dataset for the new material. Use the add-validation-dataset skill for that.