Pure Shear Stress

Pure shear stress occurs in a material when it is subjected to equal and opposite shear forces, creating a state of stress where the only non-zero stresses are shear stresses, with no normal stresses present in the plane of interest.

• For example, in torsion of circular shafts, the resulting stress state on any cross-section of the shaft is pure shear.

The shear strain ($\gamma$) is the change in right angle of stress element when subjected to pure shear stress.

Hooke’s law for shear is then:

$$\tau =G\gamma$$

where $G$ is shear modulus of elasticity (or modulus of rigidity).