On the modeling of thin-walled member assemblies combining shell and gbt-based beam finite elements: The linear and bifurcation case

In this paper, a general and efficient approach to model thin-walled members and frames with complex geometries (including tapered segments and holes). The approach combines shell and GBT-based (beam) finite elements, using each of them where it is most efficient: (i) shell elements in the plastic and geometrically complex zones, and (ii) GBT elements in the prismatic and elastic zones. To illustrate the capabilities and potential of the proposed approach, a set of numerical examples are presented, concerning linear, bifurcation (linear stability) and first-order plastic zone analyses. The examples analysed involve (i) members with tapered segments, (ii) members with holes and (iii) tapered beam-column assemblies. For validation and comparison purposes, full shell finite element solutions are provided and it is demonstrated that the proposed approach yields very accurate solutions in all cases, while involving much less DOFs.