Two-Inertia Torsional Natural Frequency Calculator
Drivetrain dynamics & rotating machinery: Model a motor-coupling-load system, calculating torsional natural frequency ($f_n$), polar moment of inertia ($J_p$), shaft torsional spring rate ($k_t$), and node position.
Drivetrain Inertias & Connecting Shaft
e.g. Electric motor / engine rotor
e.g. Compressor, pump, fan
Steel = 79.3 GPa
e.g. 2× for 4-cylinder engine, blade pass order, or VFD 6× ripple
Torsional Natural Frequency & Node Location
Torsional Frequency f_n:
--
Hertz (Hz)
Critical Speed N_crit:
--
RPM (for order n)
Shaft Stiffness k_t:
--
kN·m / rad
Node from J₁:
--
mm (zero twist)
Excitation Freq:
--
Hz (n × RPM)
Campbell Diagram Interference Check
Mode Shape Amplitude Ratio (|θ₂ / θ₁|):
--
Frequency Separation Margin:
-- %
Torsional Resonance Risk:
--
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