Compute thermal elongation ΔL = α·L·ΔT from expansion coefficient, original length and temperature change for expansion joint and fit design.
输入线膨胀系数 α、原长 L、温差 ΔT，求伸长量。
| Item | Formula / Note | Source / Standard |
|---|---|---|
| Linear thermal expansion | ΔL = alpha · L_0 · ΔT, where alpha is the coefficient of linear expansion | ISO 80000-4:2019, Quantities and units - Part 4: Mechanics |
| Final length | L = L_0 · ( 1 + alpha · ΔT ) | ISO 80000-4:2019, Quantities and units - Part 4: Mechanics |
| Volumetric expansion | For isotropic materials, beta ≈ 3 · alpha | ISO 80000-4:2019, Quantities and units - Part 4: Mechanics |
| Engineering relevance | Thermal movement must be accommodated by clearances or expansion joints | GB 50009-2012, Load code for the design of building structures (thermal action) |
Reference linear expansion coefficients and their sources (α is empirical and temperature-range dependent)
| Material | Linear expansion coefficient α | Unit | Source |
|---|---|---|---|
| Carbon steel | 11.7e-6 | K⁻¹ | ASM Handbook Vol. 1 / CRC Handbook |
| Aluminium | 23.1e-6 | K⁻¹ | ASM Handbook Vol. 2 / CRC Handbook |
| Copper | 16.5e-6 | K⁻¹ | ASM Handbook Vol. 2 / CRC Handbook |
| Austenitic stainless steel (304) | 17.3e-6 | K⁻¹ | ASTM A240 / ASM Handbook |
| Concrete | 12e-6 | K⁻¹ | ACI 318 / Eurocode 2 typical value |
| Borosilicate glass | 3.3e-6 | K⁻¹ | ISO 3585 (borosilicate glass 3.3) |
Note: values above are typical for the 20–100 ℃ range; α varies with temperature range, alloy composition and heat treatment. Use ASTM E228 measured values for precision design.