Question

What is torsional stress?

Answer 1

Torsional stress:

1. Torsional stress may be defined as that shear stress which acts on a transverse cross-section that is caused by the action of a twist.
2. Normal stress and normal strain (which are caused by tension and compression of a member) occur when a force is applied perpendicular to an area.
3. Torque on a shaft is the main cause of shear stress.
4. The torsion induced when torque is applied to a shaft causes a distribution of stress over the shaft's cross-sectional area.
5. Mathematically, Torsional stress$\left(\tau \right)=\frac{Tr}{J}$, Where $T$=Torque applied, $r=$radius of cross-section, $J=$polar moment of inertia.
6. For example, consider a traffic sign mounted on a single rod on a windy day.
7. The wind causes the sign to twist, and this twist will cause shear stress to be exerted along the cross-section of the structural member.

Thus, Torsional stress is the shear stress that acts on a transverse cross-section which is caused by the action of a twist.