Torsion:

The transmission shafts are subjected to torsion, which are used to transmit power from one plane to another parallel plane. Generally these shafts are provided in automobiles, turbines, generator, etc. These might be solid or hollow. The torque is the product of the force and the distance between the axis and the force. The torque is also called as twisting moment or turning moment.

This unit presents the treatment of members with circular, or tabular cross-sectional areas. Non-circular sections are briefly discussed. In practice, members that transmit torque, such as shafts of motors, torque tubes of powers equipment, etc. are predominantly circular or tabular in cross-section.

Objectives

After studying this unit, you should be able to

• understand the theory of torsion,
• compute the strength, angle of twist and shear strain in solid and hollow circular shaft,
• compute the power transmitted by the shaft,
• design the shaft utilizing strength requirements and stiffness requirements,
• understand the behaviour of non-circular section subjected to torsion, and
• Compute the plastic torque for several sections.