# Reference Models — Isogrid Dev Plate

Golden copies of the NX model files. **Do not modify these directly.**

Studies copy these to their own working directory before running.

## NX File Set

| File | Description | Status |
|------|-------------|--------|
| `ACS_Stack_Main_Plate_Iso_Project.prt` | NX CAD geometry — flat plate with bolt holes | ✅ Present |
| `ACS_Stack_Main_Plate_Iso_project_fem2_i.prt` | Idealized part — **must be loaded before `UpdateFemodel()`** | ✅ Present |
| `ACS_Stack_Main_Plate_Iso_project_fem2.fem` | FEM file — 3D solid mesh (CHEXA/CTETRA) | ✅ Present |
| `ACS_Stack_Main_Plate_Iso_project_sim2.sim` | Simulation — SOL 101 linear static | ✅ Present |

## Baseline FEA Results

From the baseline solid-plate solve (sim2, solution_1):

| File | Description |
|------|-------------|
| `acs_stack_main_plate_iso_project_sim2-solution_1.op2` | Binary results — used for stress field extraction |
| `acs_stack_main_plate_iso_project_sim2-solution_1.f06` | Solution text output — check for warnings/errors |
| `acs_stack_main_plate_iso_project_sim2-solution_1.dat` | Nastran input deck |
| `acs_stack_main_plate_iso_project_sim2-solution_1.log` | NX solve log |

## Key Notes

- **Idealized part is critical**: without loading `*_fem2_i.prt`, `UpdateFemodel()` silently skips mesh regeneration — parametric updates have no effect on the mesh.
- **Solver:** NX Nastran SOL 101 (linear static)
- **Units:** kg-mm-s → stress in kPa (extractor divides by 1000 → MPa)
- **Simulation name:** `sim2`, Solution `solution_1`
- **Sandboxes:** 2 regions tagged `ISOGRID_SANDBOX` in the model

## Study Setup Checklist

When creating a new study under `studies/NN_*/`, copy these files to the study's model directory:

- [ ] `ACS_Stack_Main_Plate_Iso_Project.prt`
- [ ] `ACS_Stack_Main_Plate_Iso_project_fem2_i.prt` ← **often forgotten, causes silent mesh freeze**
- [ ] `ACS_Stack_Main_Plate_Iso_project_fem2.fem`
- [ ] `ACS_Stack_Main_Plate_Iso_project_sim2.sim`

**Do NOT copy the `.op2`, `.dat`, `.f06`, `.log` files** — those are generated fresh by each solve.