Effect of Axial Deformation Caused by Torsion on a Solid Steel Cylinder

Equations describing the classical theory of applied torsion and axial rotation on a solid cylindrical shaft have been modified by Shirali and Hossain (2019) to derive new theorems, which can take into consideration axial deformation of members. The modified theorems use various empirical parameters to introduce the combined effect of axial force, axial displacement and axial rotation, which is neglected in classical theorems of torsion. Multiple finite element analysis models for solid steel cylindrical members, fixed at one end and subjected to torsion at its free end, were developed to study the effects of torsional loading. The effect of axial deformation/stress developed in the cylinder is analyzed and compared with values predicted by classical and proposed modified theorems (equations). It is shown that the cylinder can shorten or elongate when subjected to torsion. The proposed theorems/equations, based on axial deformation subjected to torsion, provide more accurate predictions of shear stress and axial rotation (angle of twist).