Abstract
This paper describes the torsional behaviour of thin-walled open sections, and deals with pure torsion and combined torsion with initial axial stress of bending moment. The narrow rectangular plate is chosen for this analysis and following assumptions are intraduced. (1) The field of small-deflection is considered. (2) The cross section is underformed and remains plane during torsion. (3) Statical behaviour of open section is equivalent to that of the gatharing of very thin-walled closed sections. (4) The yield criferion of the material is based on Von. Mises' law, and work-hardening is not taken into account. The approximate solution is obtained by nomographs for the combined torsion. The computed results are compared with the experimental results and they show good agreement under pure torsion. In case of torsion combined bending, the experimental result is investigated in early stage of twisting angle, because, when the initial bending about major axis is great, the specimen produces lateral deformation about minor axis with increasing angle of twist.
