What is torsion testing machine?

A torsion testing machine is used for determining the shear stress, modulus of rigidity, strain energy, ultimate torsional stress, etc of a material. It is mainly used in the field of Mechanical Engineering. The machine consists of two jaws. One jaw is capable of rotating whereas the other jaw remains stationary. The movable jaw is driven by an electric motor which can be operated in both forward and reverse directions.