Drive shaft fatigue strength in torsion (with notch factor)

Maximum static and dynamic (fatigue) torque for a drive shaft loaded in torsion at a critical, notched cross-section.

✓ validated against legacyoriginal: /calculators/f_1.htm

Drive shaft fatigue strength in torsion (with notch factor) — original diagram from /calculators/f_1.htm

Critical diameter, d_k10⁻³ mAllowable static torsional stress, τMPaDynamic/static torsional stress ratio, τₑ/τStress concentration factor, Kₜ or K_f

Section modulus, S = I_p/(d_k/2) = (π/16)d_k³1.57 10⁻⁶ m³

Maximum torque, statically loaded, T = S·τ785.4 Nm

Maximum torque, cyclically loaded, T = S·τₑ/Kₜ160.65 Nm

Method & references

Fatigue strength of a drive shaft loaded in torsion, at a notched/grooved cross-section.

The computation is a literal port of the original client-side JavaScript from /calculators/f_1.htm. Results are verified equal to the original by an automated golden-master test. No formula has been re-derived or “improved”.

Drive shaft fatigue strength in torsion (with notch factor) — Engineering ABC