Torsion of shafts worksheet with answers

Free printable Torsion of shafts worksheet: 6 problems from easy to exam level, with an answer key. Print it or save it as a PDF.

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1.Easy
d = 40 mmT = ?

A solid circular shaft of diameter 40 mm is made of a material with an allowable shear stress of 40 MPa. Find the largest torque Tmax the shaft can carry.

d = 40 mmτallow = 40 MPa
Tmax = N·m
2.Easy
d = 40 mmT = 1000 N·m

A solid shaft of diameter 40 mm carries a torque of 1000 N·m. Find the shear stress τρ at a radius of 5 mm from the centre.

T = 1000 N·md = 40 mmρ = 5 mm
τρ = MPa
3.Medium
do​ = ?T = 400 N·m

A hollow shaft must carry a torque of 400 N·m. Its inner diameter is to be 0.7 times its outer diameter, and the shear stress must not exceed 50 MPa. Find the smallest outer diameter do.

T = 400 N·mdi/do = 0.7τallow = 50 MPa
do = mm
4.Medium
do​ = ?T = 200 N·m

A hollow shaft must carry a torque of 200 N·m. Its inner diameter is to be 0.8 times its outer diameter, and the shear stress must not exceed 80 MPa. Find the smallest outer diameter do.

T = 200 N·mdi/do = 0.8τallow = 80 MPa
do = mm
5.Hard
Tdo​ = 40 mm, di​ = 24 mm

A hollow shaft transmits 15 kW at 3000 rpm. Find the maximum shear stress τmax in the shaft.

P = 15 kWN = 3000 rpmdo = 40 mmdi = 24 mm
τmax = MPa
6.Hard
d = ?30 kW, 750 rpm

A solid aluminium shaft transmits 30 kW at 750 rpm. The shear stress must not exceed 40 MPa and the twist must not exceed 0.25° per m of length. Find the smallest diameter d that satisfies both limits.

P = 30 kWN = 750 rpmτallow = 40 MPaθallow = 0.25°/mG = 26 GPa
d = mm

Answer key

  1. 1. Tmax = 502.7 N·m
  2. 2. τρ = 19.89 MPa
  3. 3. do = 37.71 mm
  4. 4. do = 27.83 mm
  5. 5. τmax = 4.365 MPa
  6. 6. d = 76.53 mm

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