How to design shafts on the basis of rigidity and angle of twist?

HellBoy89How to design shafts on the basis of rigidity and angle of twist?

The shafts may be designed on the basis of
1. Strength
2. Rigidity and stiffness.

In designing shafts on the basis of strength, the following cases may be considered :
(a) Shafts subjected to twisting moment or torque only,
(b) Shafts subjected to bending moment only,
(c) Shafts subjected to combined twisting and bending moments, and
(d) Shafts subjected to axial loads in addition to combined torsional and bending loads.

(Shear stress/Radius of shaft) = (Modulus of rigidity/Angle of twist)
You have to chose a shaft steel preferable 4010 steel or may be mild steel,chose a factor of safety,and safe design stress.By that you can estimate the radius of shaft by putting in the values of modulus of rigidity and angle of twist.