非对称开口薄壁型钢截面构件的稳定性设计理论

Cold-formed thin-walled open-section members are extensively used in constructions due to the material efficiency and ease of manufacturing. Such members are usually slender and susceptible to buckling, where the buckling modes are usually coupled and complicated. Current stability method is based on the linear elastic analysis method associated with the use of empirical formulations, which is usually conservative. Further, asymmetric shapes are commonly fabricated for cold-formed sections, where the shear center and the geometric center are not coincident. When using the conventional beam-column elements with the symmetric section assumption, the error in the prediction of buckling strengths can be quite large. A new type of beam-column element with warped degree of freedom and asymmetric section assumption is introduced, and the stability analysis theory for various kinds of cold-formed thin-walled steel members with arbitrarily-shaped section is proposed. This method can directly capture the buckling behaviors of thin-walled members, eliminating the needs in adopting the empirical assumptions, such as the effective lengths. This paper briefly explains the proposed stability design theory, the derivation procedure of the new warping beam-column element and the cross-section analysis algorithm. Finally, several examples are provided for validating and verifying the proposed method for the stability design of cold-formed thin-walled open-section members.