DESCRIPTION

Technical Description

Torsion occurs primarily on axles and drive shafts in motor vehicles and machines. The torsion occurring in the shaft cause cross-sections of the shaft to be pushed together around the longitudinal axis. When a torque is applied to a shaft the cross-section remains flat and no warpage occurs.

In the event of minor torsion the length and radius remain unchanged. The straight lines on the outer circumference of the shaft running parallel to the axis become helixes. Non-circular cross-sections mostly result in warpage.

SE 110.29 investigates the torsion of a bar under a torque. The bar is clamped into two movable bearing blocks by a chuck. The torque is generated by a circular disc, a deflection roller and a load. The clamping length and torque can be varied. The resultant torsion is read-off at two random points on the bar by means of angle indicators.

The fundamentals of elastic torsion are illustrated by the round bar. Three other bars are provided in order to investigate special cases: two thin-walled enclosed sections (a tube and a square tube) and a longitudinally slotted tube (thin-walled open section).

All the component elements of the experiment are clearly laid-out and housed securely in a storage system. The complete experimental setup is arranged in the frame SE 112.

The well-structured instructional material sets out the fundamentals and provides a step-by-step guide through the experiments.

Learning Objectives / Experiments

- torsion of a bar
- shear modulus of elasticity and 2^nd polar moment of area
- angle of twist dependent on clamping length
- angle of twist dependent on torque
- influence of rigidity on torsion
  * round bar with full cross-section
  * tube
  * tube, longitudinally slotted
  * square tube
- calculation of angle of twist
- comparison of calculated and measured angle of  twist