In mechanics and geology, pure shear is a three-dimensional homogeneous flattening of a body. It is an example of irrotational strain in which body is elongated in one direction while being shortened perpendicularly. For soft materials, such as rubber, a strain state of pure shear is often used for characterizing hyperelastic and fracture mechanical behaviour. Pure shear is differentiated from simple shear in that pure shear involves no rigid body rotation.

If is the stretch ratio applied to the material, then the deformation gradient in pure shear can be expressed as

The linear elastic stress-strain law for the case of pure shear is:



This article uses material from the Wikipedia article Pure shear, which is released under the Creative Commons Attribution-Share-Alike License 3.0.