Torsion: Deriving Hooke's Law and Solving Torsion Problems

This lecture covers torsional loads on rotationally symmetric bars, deriving Hooke's law for torsion, and solving torsion problems using superposition. Topics include stresses and strains induced by torsion, relationships between angle of twist, shear strain, shear stress, and load, calculating the second moment of area, and solving torsion problems. Useful statements about torsion, applying Hooke's law, and equilibrium in torsion are discussed. Examples of torsion in hollow shafts and composite shafts are presented, along with comparisons between different materials. The lecture also explores measuring the rigidity modulus in torsional tests and analyzing normal load versus torsion in various structures.