Torsional stress is the stress experienced by a material or structural component when subjected to twisting or torsional loads, The formula for calculating torsional stress depends on the geometry of the component and the applied torque. For a circular shaft or rod with radius and subjected to a torque , the formula for torsional stress is given by:
where:
- = Torsional stress (in pascals, Pa or N/m²)
- = Torque applied to the shaft (in newton-meters, N·m)
- = Radius of the shaft (in meters, m)
- = Polar moment of inertia of the shaft’s cross-sectional area (in meters to the fourth power, m⁴)