Stiffness method of thin-walled beams with closed cross-section

The aim of the present study is to present a general stiffness method capable of analyzing three-dimensional thin-walled straight beams with closed cross-sections. The method based on the assumptions introduced by Benscoter is suited for automatic computation on computers. Starting from the principle of virtual displacement, an exact stiffness matrix and vector of fixed-end reactions for the analysis of thin-walled beam with an arbitrary closed cross-section are derived. The method is illustrated by example.