Poissons Ratio⚠ unverified
Physics / Materials · Compute Poisson's ratio
Parameters
| Input | Symbol | Unit | Default | Description |
|---|---|---|---|---|
| lateral_strain | lateralstrain | — | 1.0 | Strain measured transverse to the loading direction, dimensionless |
| axial_strain | axialstrain | — | 1.0 | Strain measured along the loading direction, dimensionless |
| Output | Symbol | Unit | Description |
|---|---|---|---|
| result | ν | — | Poisson's ratio, dimensionless |
The science & history
Understanding the Parameters
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Strains — include signs: the leading minus in the formula makes $\nu > 0$ for ordinary materials (lateral contraction in tension).
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$\nu$ — links $E$, $G$, and bulk modulus for isotropic linear elasticity ($G = E/[2(1+\nu)]$).
Derivation (Approaching a Proof)
Definition under uniaxial stress: measured lateral strain over axial strain with a minus sign so $\nu$ is positive for volume-preserving-ish solids. Not derived from simpler elastic constants without isotropy assumptions — it is a material constant in isotropic Hooke’s law.
History
Siméon Poisson; essential third isotropic elastic constant alongside $E$ (or $G$).
Related Concepts: Hooke's Law strain, Hookes Law Strain Stress, Strain Energy Density
Notes: Registry calculator poissons-ratio (unverified). Uniaxial definition.