Torsional Moment-Stress

Calculate the max stress because of torsional moment on the outer layer of a steel hollow rod when two forces act on it from a distance of 50mm from the center.

Solution

T = 300KN * 0.1 = 30KNm

Polar moment of inertia for hollow rod.

J = (π/2) * (R⁴₂ - R⁴₁) = (3.14/2) * (0.025⁴ - 0.010⁴) = 5.976 * 10^-7m⁴

Maximum stress at the outer layer.

t_max = (T * R₂) / J = (30KNm * 0.025m) / (5.976 * 10-7m⁴) = 1.255E + 6 N/m²