# Study 03 — Robustness Checks

**Type:** Parametric — Specific Scenarios
**Runs:** 8
**Model:** Uses both .sim setups (CBUSH for K tests, displacement for correlated tests)
**Prerequisite:** Complete Studies 01 and 02 first (needs knee values)

## What This Does

Tests scenarios that the simple sweeps can't capture:

1. **One-soft-point (3 runs):** What if one support is 10× softer than the rest?
2. **Combined compliance (3 runs):** Both vertical and lateral at knee values simultaneously
3. **Correlated displacement (2 runs):** All verticals move together (frame bending mode simulation)

## Before Running

Update `atomizer_spec.json` with actual knee values from Study 02:
- Replace `KNEE` placeholders with K_vert_knee and K_lat_knee values
- Replace `KNEE/10` with knee/10, `KNEE/2` with knee/2

## Output

- Interaction factor: is combined ΔWFE > sum of individual?
- Worst-case single soft point identification
- Correlated vs independent displacement comparison