Extended GBT formulation for eigenvalue buckling analyses of thin-walled members with edge-stiffened holes: Fid-Bau Portal

Extended GBT formulation for eigenvalue buckling analyses of thin-walled members with edge-stiffened holes

Duan, Liping / Miao, Ji / Li, Hai-Ting / Zhao, Jincheng

Highlights • GBT-based eigenvalue buckling analyses of thin-walled members with edge-stiffened holes. • Mortar method for connecting XGBT with MITC4 shell finite elements. • XGBT modeling of the unstiffened perforated members and MITC4 shell FE modeling of the stiffeners. • Numerical implementation and validation of the proposed XGBT approach. • Pure buckling mode identification from the coupled buckled shapes for members with edge-stiffened holes.

Abstract Cold-formed steel sections with edge-stiffened holes exhibit increasing popularity in the building industry. This paper extends the generalized beam theory (GBT) to the scope of handling this kind of members so that modal decomposition of the coupled buckling modes of these members into the set of pure buckling modes can be realized, which is essential for a direct strength method (DSM)-based design. The presented GBT formulation is built upon the XGBT approach that was previously proposed by the authors (Duan and Zhao, 2021; Duan et al., 2022; Duan and Zhao, 2022) [1–3] for handling the un-stiffened perforated steel profiles, but its novelty lies in the scheme used to connect the previous approach to the MITC4 shell FEs. Specifically, the previous GBT-based beam FEs are employed to handle the perforated member but without stiffeners, and the MITC4 shell FEs are used to model the stiffeners along the hole edges; further, the mortar method-based interface elements are employed to weakly ensure the compatibility between the shell and the GBT-based FEs no matter how mismatched their meshes are. Three illustrative examples are presented to show the potential of the proposed approach, where linear buckling analysis results for the members with circular holes obtained by the present GBT are compared with those obtained by the ANSYS shell FE analyses. The presented approach shows advantages in computational costs and interpretability of the obtained results over the shell model.