IN these days of metal construction, the aircraft designer frequently uses the socalled Batho theory of the torsion of thin shells. This simple and wellknown theory is a ecial case, applicable to tubes and boxes of any crosssection, of the general St. Venant torsion theory. The same theory, applied to thin open sections, of which a channel is a mplc example, gives the result that the torsional strength and rigidity are very small. While it is true that such a section tends always to be weak in torsion in comparison with a closed section of similar dimensions, subject to certain conditions as regards fixing of the ends it is capable of transmitting an appreciable torque. The method of transmission can be described as differential bending of the two langes, in the case of the channel. Calculation of differential bending stresses in a twospar wing under torsion is a simple procedure, but alien the two members in differential bend form part of a continuous section, the conditions are somewhat altered. The general theory applicable to such cases may be called the theory of torsionbending. The results of this theory will be summarised, and the proofs given in the Appendix.
Aircraft Engineering and Aerospace Technology – Emerald Publishing
Published: Oct 1, 1938