Twist and stored-energy arithmetic

Coupling torsion

Inputs

Declared transmitted torqueTUser-entered torque at the stated coupling operating point; transient duty is excluded.

Declared torsional stiffnessktN·m/radUser-entered linear coupling torsional stiffness; geometry and supplier data are not inferred.

Declared elastic twistφ

0.020833

Linear elastic stored energyU

2.6042

θ = T/kt; U = T²/(2kt)

A first-pass number, not a code check, certification, or approval. Read the method and its limits below. What this is and is not.

Calculation snapshot

Formula version 1.0.0

Declared transmitted torque	250
Declared torsional stiffness	12000

Declared elastic twist	0.020833 rad
Declared elastic twist	1.1937 deg
Linear elastic stored energy	2.6042 J

θ = T/kt · U = T²/(2kt)

SDP/SI coupling stiffness context: https://sdp-si.com/Rivin/art2.php

This printout is a record of displayed inputs and deterministic formula output. It is not an approval, certification, or engineering conclusion.

Method

Calculate the elastic twist and stored energy from a coupling torque and torsional stiffness without selecting or qualifying a coupling.

θ = T/kt; U = T²/(2kt)

When

Don’t

This is declared linear torsional stiffness arithmetic for a coupling. It excludes coupling selection, torque capacity, flexible-element geometry, fatigue, resonance, damping, misalignment, shaft/bearing loads, safety, and approval.