Poisson's Ratio Calculator
Determine Poisson's ratio from measured lateral and axial strains during a uniaxial test.
Poisson's Ratio (nu)
0.300
Poisson's Ratio (nu) vs Lateral Strain (transverse)
Formule
## Poisson's Ratio When a material is stretched, it contracts laterally. Poisson's ratio quantifies this coupling. ### Formula **nu = -epsilon_lateral / epsilon_axial** Since lateral strain is opposite in sign to axial strain, nu is positive. Most metals have nu between 0.25 and 0.35. Steel is approximately 0.30, aluminium 0.33, rubber approaches 0.50 (incompressible). Cork is near zero.
Exemple Résolu
A steel rod under tension shows 0.001 axial strain and 0.0003 lateral contraction.
- 01nu = 0.0003 / 0.001 = 0.300
- 02This is a typical value for structural steel.
Questions Fréquentes
What are typical Poisson's ratio values?
Steel: 0.27-0.30, aluminium: 0.33, copper: 0.34, concrete: 0.15-0.20, rubber: 0.49-0.50, cork: approximately 0. Most engineering metals fall between 0.25 and 0.35.
Can Poisson's ratio exceed 0.5?
For isotropic materials, thermodynamic stability requires nu between -1 and 0.5. Values above 0.5 would imply volume increase under compression, which is physically impossible for conventional materials. Some auxetic metamaterials have negative Poisson's ratios.
Why does Poisson's ratio matter in engineering?
It affects multiaxial stress states, plate bending, thermal expansion analysis, and wave propagation. In pressure vessels and confined structures, lateral restraint creates significant secondary stresses governed by nu.
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