Distortion of Thin-Walled Open-Cross-Section Members : One-Degree-of-Freedom and Singly Symmetrical Cross-Sections

Abstract

The essential features of the distortional deformation of an open-cross-section member are studied. The analytical models are restricted to the members of one-degree-of-freedom. The assumptions used in the semi-membrane theory are employed, and one dimensional analytical method applicable to distortional deformation is introduced. The concept of two shear centers of distortion can be introduced. This is an extended concept of a centroid and a torsional shear center. The distortional bimoment introduced here should be taken into consideration as a generalized force. According to the results of the calculation of a cantilever, the stress value at the fixed end has the possibility of being about twice as high as the value of the conventional beam theory.