Shear Modulus

In materials science, shear modulus or modulus of rigidity, denoted by G, or sometimes S or μ, is defined as the ratio of shear stress to the shear strain:

where

= shear stress;

is the force which acts

is the area on which the force acts

in engineering, = shear strain. Elsewhere,

is the transverse displacement

is the initial length

Shear modulus' derived SI unit is the pascal (Pa), although it is usually expressed in gigapascals (GPa) or in thousands of pounds per square inch (kpsi).

The shear modulus is always positive.