Lecture
This lecture covers the torsion of axisymmetric cross sections, focusing on circular bars of linearly elastic materials and their efficiency in resisting torsional loads. It explains the shear stresses distribution in solid circular bars and circular tubes, the angle of twist related to applied torque, and the polar moment of inertia. Through examples, the instructor demonstrates how to determine the required sizes of solid bars and circular tubes based on allowable stresses and rates of twist, highlighting the efficiency of circular tubes in material usage. Additionally, it discusses stresses and strains in pure shear, including the application of Hooke's law for linearly elastic materials and the corresponding maximum shear strain at 45°.