UNIVERSITY of PLYMOUTH

 

MECH115: Engineering Science 1

 

Tutorial examples: - Torsion                                                  [Use g = 9.81 m/s² where required]

 

 

  1. For each of the following circular shafts find the polar moment of inertia, J, in cm4.    [ 981.7 cm4, 981.4 cm4 ]

 

 

 

 

 

 

 

 

 

 

 




  1. For each of the above circular shafts in Question 1 find the surface shear stress induced when each is subject to a torque of 479 Nm. For the hollow shaft find also the shear stress on the inner surface. [ 2.44 MN/m2 and 2.93 & 2.48 MN/m2 ]



3.      If the solid shaft in Question 1 is made from an aluminium alloy, and the hollow shaft is made from high density nylon, find the angle of twist for a 1 meter length of shaft in both cases where the applied torque is 100 Nm. Gnylon = 0.9 GN/m2, and Galloy = 27 GN/m2.   [ 0.022º, 0.649º ]



  1. A motor car transmission shaft is 2m long, and 45mm in diameter. At maximum acceleration the engine applies a torque to the shaft and on test, it was found that the shaft twisted by 2.795 degrees. If the Shear Modulus (G) for the shaft material is 82GN/m² find the maximum shear stress in the shaft.         [45.0 MN/m²]

 

 

  1. A hollow tube 25mm OD, 19mm ID and 400mm in length is required to transmit a torque of 30Nm. The angle of twist must be less than 0.5º. The tube would be best made from an aluminium alloy (for lightness), but an alternative would be steel. Check to see whether either material could be used.  Gsteel = 80 GN/m2, and Galloy = 27 GN/m2.    [steel only]

 

 

 

 

 

 

 

115tut_torsion