Metric and Imperial Units

The above formulas may be used with both imperial and metric units. As with all calculations care must be taken to keep consistent units throughout with examples of units which should be adopted listed below:

Notation

• d = diameter under consideration, in or mm
• L = length under consideration, in or mm
• G = shear modulus or modulus of rigidity, psi or MPa
• J = polar moment of inertia, in⁴ or mm⁴
• T = applied or resulting torsion, lb.in or Nmm
• θ = angle of twist, degrees
• τ = shear stress, psi or MPa

1. A.F. Hughes, D.C. Iles, A.S. Malik. Design of Steel Beams in Torsion. UK. 2011. Print.
2. G.E. Maddux, Air Force Flight Dynamics Laboratory. Strees Analysis Manual. U.S. 1970. Print.