Combined Torsion & Bending
With simultaneous bending M and torque T, find diameter by equivalent bending-moment and equivalent torque methods; take the larger.
Inputs
Formula
Me=√(M²+(αT)²); Te=√((αM)²+T²); d=max(∛(32Me/(π[σ])), ∛(16Te/(π[τ])))
How to use
- Fill in Bending M, Torque T, Allow. bend. [σ], Allow. shear [τ], Equiv. factor α in the Inputs section (watch the unit on each field).
- Click Calculate; the tool evaluates the formula shown above.
- Read By equiv. moment, By equiv. torque, Recommended in the results area.
Formula notesCombined bending+torsion (max shear): σ_eq = √(σ_b² + 4τ²) ≤ [σ]; σ_b = M/W, τ = T/W_p.