Comparison of dynamic torsion theories for beams of elliptical cross-section

A comparison between several dynamic torsion theories for beams of non-circular cross-section and their predicted torsional wave first branch dispersion characteristics is made with some recently published "exact" data for elliptical cross-section beams of various eccentricities. Closest agreement, in particular for short wavelengths, is provided by two theories, both of which allow in-plane distortion of the section; however, a simpler theory adjusted to predict phase velocity asymptotic to Rayleigh surface wave velocity at short wavelengths gives closest overall agreement and appears preferable for torsional wave propagation and standing wave frequency analysis.