# Steel — AISI 1005

**Status:** Baseline material confirmed (Gen 002)
**NX Material Name:** "beam material" (inherited by thin shell property)

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## Properties

| Property | Value | Units | Source | Confidence |
|----------|-------|-------|--------|------------|
| Standard | AISI / SAE | — | KBS session | ✅ Confirmed |
| Grade | **1005** | — | KBS session ("NSE steel 10 or 5" = ANSI Steel 1005) | ✅ Confirmed |
| Density | **7.3** | g/cm³ (7,300 kg/m³) | KBS session — Antoine stated directly | ✅ Confirmed |
| E (Young's modulus) | ~200 | GPa | Typical for AISI 1005 — **needs NX verification** | 🟡 Estimated |
| Yield strength | ~285 | MPa | Typical for AISI 1005 (cold-drawn) — **needs NX verification** | 🟡 Estimated |
| UTS | ~330 | MPa | Typical for AISI 1005 — **needs NX verification** | 🟡 Estimated |
| Poisson's ratio | ~0.29 | — | Typical for carbon steel — **needs NX verification** | 🟡 Estimated |
| Elongation | ~20 | % | Typical for AISI 1005 — **needs verification** | 🟡 Estimated |

## Notes on AISI 1005

- AISI 1005 is a **low-carbon plain steel** (0.06% max C) in the 10xx series
- Commonly used for structural applications — good weldability, moderate strength
- NX material library designation may vary (Antoine said "NSE steel 10 or 5" which maps to ANSI/AISI Steel 1005)
- **Density note:** Antoine stated 7.3 g/cm³. Standard steel is 7.85 g/cm³. The 7.3 value may be the NX library default or a specific setting. This affects mass calculation directly.

## Stress Allowable

| Parameter | Value | Basis | Status |
|-----------|-------|-------|--------|
| Stress constraint | 130 MPa | From intake — Gap G9 | 🟡 Not yet confirmed for Gen 002 |
| Implied safety factor | ~2.2 | vs. 285 MPa yield (estimated) | Conservative |

> ⚠️ Need to confirm whether the 130 MPa stress limit from Gen 001 intake still applies given the mass discrepancy resolution. The 130 MPa may have been set for the ~974 kg model.

## Future Material Expansion

Antoine explicitly requested future material support (KBS session 20260210-163801):

| Material | Standard | Priority | Notes |
|----------|----------|----------|-------|
| **Aluminum 6061** | — | Future | Antoine: "change this type of material for aluminum, 6061" |
| **Stainless Steel ANSI 310** | ANSI 310 | Future | Antoine: "stainless steel. ANSI, let's say 310" |

> Antoine's instruction: "Don't start with [these]. Just add this as a future expansion for the optimization process."

### Material Expansion Implications

- Multi-material optimization would change the problem fundamentally:
  - Different E, ρ, σ_y for each material → different optimal geometries
  - Could be handled as a categorical DV or separate optimization runs per material
  - Aluminum 6061: E ≈ 69 GPa, ρ ≈ 2.7 g/cm³, σ_y ≈ 276 MPa — lighter but much less stiff
  - SS 310: E ≈ 200 GPa, ρ ≈ 8.0 g/cm³, σ_y ≈ 205 MPa — heavier, similar stiffness, lower yield

## History

- **Gen 001** (2026-02-09): Placeholder — only knew "Steel (AISI)"
- **Gen 002** (2026-02-10): Confirmed AISI 1005 from KBS session. Density confirmed 7.3 g/cm³. Future materials flagged (Al 6061, SS 310). Typical mechanical properties added (pending NX verification).