Anti-buckling effect and ultimate load-bearing capacity of thin-walled steel compression members

Analytical theories related to the buckling criterion and strength of thin-walled structures are classified into flat plate and cylindrical shell theories and others (conical shell and spherical shell). To discuss the accurate predictions for the ultimate load-bearing capacities (ULBCs) of thin-walled steel (TWS) composite members under longitudinal compression and solve the long-standing problem of the different effective width (EW) definitions under different main TWS structural specifications, a simple model of a flat element supported in parallel by two cylindrical shell elements (corner ridgelines) on both longitudinal sides was analyzed. In addition, a simplified method to evaluate the reduction factor of the postbuckling ULBC caused by the initial imperfections was developed. The rational results for releasing additional anti-buckling functions of the ridgeline revealed herein are expected to be beneficial to the structural lightweight optimization for not only civil and construction engineering but also other broad areas such as spacecraft and aircraft engineering.