sentences:  Shear strain is distinguished from volumetric strain, the change in a material's volume in response to stress and change of angle is called has angle of shear
  
  Often, the verb "shearing" refers more specifically to a mechanical process that causes a plastic shear strain in a material, rather than causing a merely elastic one.A plastic shear strain is a continuous (non-fracturing) deformation that is irreversible, such that the material does not recover its original shape.It occurs when the material is yielding.