Question

what is pure torsion?

Answer 1

1. Torsion is the twisting of an object due to an applied torque.
2. The SI unit of torsion is pascal (Pa).
3. Normally two types of stresses are induced in a circular shaft they are
   3.1 Due to the transmission of torque torsional stresses occur.
   3.2 Due to the weight of pully, gear, etc. mounted on the shaft bending stresses occur.
4. The shaft must be straight and should have a uniform cross-section.
5. The circular shaft is said to be in the state of pure torsion.
6. When the circular shaft is subjected to torque only without being acted upon by any bending moment.
7. Torsional shear stress can be thought of as the shear stress produced on a shaft due to twisting.
8. Torsion mathematical equation:
   $\frac{\mathrm{T}}{\mathrm{I}}=\frac{\mathrm{\tau }}{\mathrm{R}}=\frac{\mathrm{C\theta }}{\mathrm{L}}$
   where,
   $\mathrm{T}$= torque
   $\mathrm{I}$= polar moment of inertia
   $\mathrm{\tau }$= shear stress
   $\mathrm{R}$= radius of curvature
   $\mathrm{C}$=moment of rigidity
   $\mathrm{\theta }$= angle of torsion
   $\mathrm{L}$= length of the shaft