Poisson's Ratio of Aluminium

\nu_{\mathrm{Al}} = 0.33\ \text{—}

Value	0.33 —
Status	Measured: ± 0.01 — (0.03 relative)
Source	ASM Handbook, Vol. 2: Properties of Nonferrous Alloys
Categories	Material Properties Engineering & Trade mechanics

ν_Al in every dimensionless unit

ratio	0.33 —
percent	33 %

Learning zone

Aluminium contracts laterally by about a third of its axial strain, a shade more than steel. The number is close enough to steel's that swapping materials rarely changes a hand calculation, but it is what makes G come out at 26 GPa rather than 25.7, and it feeds the same strain-gauge, plate-bending and pressure-vessel relations.

Poisson's ratio is bounded for real isotropic materials between −1 and 0.5, and almost everything metallic lands between 0.25 and 0.35 — cork is famously near zero, rubber near 0.5, and engineered auxetic foams manage negative values by unfolding re-entrant cells. As with steel, this is an elastic-range value: plastic deformation is volume-conserving and drives the apparent ratio toward 0.5. Anisotropic materials such as rolled sheet, timber and composites have a different ratio for every pair of directions, so a single figure for them is a fiction.

Used by these solvers

Poisson's Ratio

\nu = \frac{\varepsilon_{lat}}{\varepsilon_{ax}}

Relation Between E, G and ν

E = 2G(1 + \nu)

Shear Modulus (G = τ/γ)

G = \frac{\tau}{\gamma}