Geometric stress concentration for a grooved shaft in torsion

Geometric stress concentration factor Kt = A(r/d)^b for a grooved shaft loaded in torsion, from chart-fit coefficients A, b keyed on the D/d ratio (r/d clamped to 0.1 above its 0.3 validity limit, as in the legacy page).

✓ validated against legacyoriginal: /calculators/e1_3c.htm
Geometric stress concentration, Kₜ1.51
Coefficient, A0.90182
Coefficient, b-0.22334

Method & references

  • Kt = A(r/d)^b for a grooved shaft in torsion. Valid for r/d ≤ 0.3.

The computation is a literal port of the original client-side JavaScript from /calculators/e1_3c.htm. Results are verified equal to the original by an automated golden-master test. No formula has been re-derived or “improved”.

Geometric stress concentration for a grooved shaft in torsion — Engineering ABC