Floating Ball Valve Stem Strength Calculator

Multi-section stem torsional stress verification: I-I rectangular, II-II annular, III-III circular, IV-IV rectangular, and neck bending stress.

I-I: τN = Mm / W, W = 0.9α·b·a²
II-II: τ = (D+d)²·P / (16·d·H)
III-III: τ' = M / (π/16·d³)
IV-IV: τ" = M / W
Neck: σzy = Mm / (0.12·a_neck²·h)

Input Parameters

Ball Seal Torque Mm N.mm

Total Torque M N.mm

Stem Width a mm

Stem Length b mm

Coefficient α -

Shoulder Outer Dia D mm

Stem Dia d mm

Shoulder Height H mm

Neck Width a_neck mm

Neck Height h mm

Pressure P MPa

Allowable [τN] MPa

Allowable [τ] MPa

Allowable [σzy] MPa

Section Modulus W1 mm³—

I-I Stress τN MPa—

II-II Stress τ MPa—

Circular W3 mm³—

III-III Stress τ' MPa—

IV-IV Stress τ" MPa—

Neck Stress σzy MPa—

All ≤ Allowable—