# Torsion Constant for Ellipse Cross-section

Written by Jerry Ratzlaff on . Posted in Classical Mechanics

### Torsion Constant for Ellipse Cross-section formula

$$\large{ J = \frac{\pi\;a^3\;b^3}{a^2\;+\;b^2} }$$

Where:

$$\large{ J }$$  (Greek symbol alpha) = torsion constant

$$\large{ a }$$ = semi-major axis of an ellipse

$$\large{ b }$$ = semi-minor axis of an ellipse

$$\large{ \pi }$$ = Pi