Poynting Effect

The Poynting Effect is a physical phenomenon where a material, like a metal or rubber, changes length when it is stretched or compressed. Specifically, when you stretch a rod, it tends to become slightly thicker in diameter; when compressed, it may lengthen or become thinner, depending on the material. This behavior occurs because of the internal forces and the way the material’s molecules react to deformation, causing a coupling between axial and lateral strains. The Poynting Effect is important in engineering applications where precise deformation behavior of materials under load needs to be understood and predicted.