ABSTRACT
Prior to proving the above formula, the following assumptions are made for circular section shafts:
(a) the shaft is of circular cross-section (b) the cross-section of the shaft is uniform along its
entire length (c) the shaft is straight and not bent (d) the shaft’s material is homogeneous (i.e. uniform)
and isotropic (i.e. exhibits properties with the same values when measured along different axes) and obeys Hooke’s law
(e) the limit of proportionality is not exceeded and the angles of twist due to the torque are small
(f) plane cross-sections remain plane and normal during twisting
(g) radial lines across the shaft’s cross-section remain straight and radial during twisting.
