Question

The value of Poisson's ratio depends on

• A. material of the test specimen
• B. magnitude of the load
• C. cross section
• D. None of these

Answer 1

Answer:

A. material of the test specimen

Poisson's ratio is the ratio of transverse contraction strain to longitudinal extension strain in the direction of the stretching force. It depends on the type of material, with most materials having values ranging between 0.0 and 0.5. Rubber has a Poisson ratio of nearly 0.5, while cork's Poisson ratio is close to 0. A perfectly incompressible material deformed elastically at small strains would have a Poisson's ratio of exactly 0.5. Most steels and rigid polymers exhibit values of about 0.3 before yield, increasing to 0.5 for post-yield deformation occurring deformation occurring largely at constant volume.