In Pella, we learned that oak expands 5× slower than aluminum. On a Mars dome, that difference kills seals and buckles struts. This workbench takes Austin Danos's principle—wood responds differently to heat—and extends it to the alloys holding our habitat together. Input your material, your temperature swing, and your tolerance. Get the stress before the fracture.
Input Parameters
Results
Stress: σ = E · ε = E · (ΔL/L₀)
Source: ISO 80000-5:2019, Wikidata Q74760821
| Material | α (×10⁻⁶ K⁻¹) | Yield (MPa) | E (GPa) | Dome Application |
|---|---|---|---|---|
| Carbon Steel | 6.5 | 350–550 | 200 | Primary structural ribs |
| Aluminum 6061 | 23.0 | 276 | 69 | Thermal exchange panels |
| Titanium Grade 5 | 16.5 | 880 | 114 | High-stress joints |
| Inconel 718 | 9.0 | 1200 | 208 | Cryo-seals & reactor casings |
| Maple (long.) | 5.4 | 70 | 11 | Interior fixtures (low stress) |
| Oak (tang.) | 35.0 | 65 | 12 | ❌ Avoid in thermal zones |
Wood values adjusted for moisture content 12% equilibrium.
The Iowa Lesson: At Pella's furniture shop, we watched maple bench tops warp when the kiln swung 40°C overnight. The tangential grain expanded 6× faster than longitudinal. We learned to orient grain against the stress vector.
The Mars Extension: Our dome faces a 250K swing (day to night). Carbon steel ribs expand 1.95mm per meter. Titanium joints expand 4.125mm. Mismatch them, and the seal tears at the flange. This calculator prevents that tear.
Formula Chain:
1. Linear expansion: ΔL = α · L₀ · ΔT
2. Thermal strain: ε = ΔL / L₀ = α · ΔT
3. Induced stress (if constrained): σ = E · ε = E · α · ΔT
4. Safety margin: SM = [(σ_yield − σ_induced) / σ_yield] × 100%
Grounded in: https://4ort.xyz/entity/coefficient-of-thermal-expansion