Poisson Ratio

Tells how much a material streteches/deforms laterally relative to the load

$\nu =-\frac{\mathrm{d}{\epsilon }_{\text{trans}}}{\mathrm{d}{\epsilon }_{\text{axial}}}$

• ${\epsilon }_{\text{trans}}$ is the strain in the direction perpendicular to the load
• ${\epsilon }_{\text{axial}}$ is the strain in the direction along the axis of the load
• More brittle materials generally have lower Poisson ratios while more elastic materials have higher Poisson ratios