On the combination of shell and GBT-based beam finite elements

This paper proposes a quite general and computationally efficient approach to model thin-walled members and frames with complex geometries (including tapered and perforated members). The approach consists of combining shell and GBT-based (beam) finite elements, using each element type where it is most advantageous: (i) shell elements are assigned to the plastic and geometrically complex zones, whereas (ii) GBT elements are employed in the prismatic and elastic zones. To illustrate the capabilities and potential of the proposed approach, several numerical examples are presented, involving linear (first-order) static, bifurcation (linear stability), undamped free vibration, dynamic and first-order plastic zone analyses. The examples analyzed deal with (i) members with tapered segments, (ii) perforated members and (iii) complex beam-column assemblies. For validation and comparison purposes, full shell finite element solutions are provided, showing that an excellent match is obtained in all cases.