3 - Torsion of circular shafts

Abstract

This chapter discusses the theory of torsion of circular shafts. In developing the simple theory of torsion, it is assumed that: (1) the material of the shaft is completely homogeneous, that is, its molecular structure is the same throughout; (2) the material of the shaft is elastic and, within the elastic limit, obeys Hooke's law; (3) cross-sections that are plane and at right angles to the longitudinal axis of the shaft before twisting remain plane and at right angles to the axis after twisting; and (4) during twisting, the shaft remains circular. The shear stress varies from zero at the centre to a maximum value at the outside diameter. The shear stress varies from a minimum at the bore to a maximum value at the outside diameter.