Poisson Ratio Calculator
Calculate Poisson's ratio from lateral and axial strain measurements during uniaxial loading.
Poisson's Ratio (nu)
0.3000
Poisson's Ratio (nu) vs Lateral Strain (epsilon_lateral)
Formule
## Poisson's Ratio When a material is stretched in one direction, it contracts in the perpendicular directions. Poisson's ratio quantifies this coupling between axial and lateral strains. ### Formula **nu = -epsilon_lateral / epsilon_axial** By convention, the negative sign makes nu positive for normal materials (since lateral strain is opposite in sign to axial strain). For this calculator, enter both strains as positive magnitudes. Most metals have nu between 0.25 and 0.35. Rubber approaches 0.5 (nearly incompressible).
Exemple Résolu
A steel bar shows 0.001 axial strain and 0.0003 lateral contraction strain.
- 01nu = 0.0003 / 0.001 = 0.3
- 02This is typical for steel (nu ≈ 0.28-0.33)
Questions Fréquentes
What are typical Poisson ratio values?
Steel: 0.27-0.30, aluminum: 0.33, copper: 0.34, rubber: ~0.50, cork: ~0, concrete: 0.15-0.20. Auxetic materials have negative Poisson ratio (they expand laterally when stretched).
Can Poisson ratio exceed 0.5?
For isotropic materials, thermodynamic stability requires -1 < nu < 0.5. A value of 0.5 means the material is perfectly incompressible. Some anisotropic materials can have nu > 0.5 in certain directions.
How does Poisson ratio relate to compressibility?
Bulk modulus K = E / (3(1 - 2*nu)). As nu approaches 0.5, K approaches infinity, meaning the material becomes incompressible. Rubber (nu ≈ 0.499) is nearly incompressible.
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