shear stress

Side view of a parallelepiped where a shearing force is applied to the top of a rectangular cuboid while the bottom is held in place. The resulting shear stress, τ, deforms the cuboid's rectangular side into a parallelogram. The area involved would be the top of the parallelopiped. Perspective view of a parallelepiped where a shearing force F is applied to the top of a rectangular cuboid with area A while the bottom is held in place. The resulting shear stress deforms the cuboid's rectangular side into a parallelogram.

Shear stress (often denoted by τ, Greek: tau) is the component of stress coplanar with a material cross section. It arises from the shear force, the component of force vector parallel to the material cross section. Normal stress, on the other hand, arises from the force vector component perpendicular to the material cross section on which it acts.