Alphonse J. C. B. Duleau
(1789-1832)

The French engineer Alphonse J. C. B. Duleau performed tests on bars in torsion and also developed a theory for circular bars.

From Mechanics of Materials, 4th Ed., by J.M. Gere and S.P. Timoshenko, PWS Publishing, 1997, pp. 835-42.