what is poisson ratio
Poisson's ratio is. 1  the ratio of the relative contraction strain (or transverse strain) normal to the applied load-to the relative extension strain (or axial strain) in the direction of the applied load.hen a material is stretched in one direction it tends to get thinner in the other two directions. Î¼ = - Îµt / Îµl (1) where Î¼ = Poisson's ratio Îµt = transverse strain Îµl = longitudinal or axial strain.