Dynamic Characterization and Assembly Methods of Full-Scale Aluminum Plate-Based Tensegrity Structure

Tensegrity structures are a type of bar and cable structure that have a high strength-to-weight ratio and can easily be built into modular and adaptive structures. Plate-based tensegrity structures introduce a plate as a third element type. In addition to previously performed static analysis, there are still several design considerations which must be assessed in order to enable full-scale construction of a plate-based tensegrity structure. Namely, self-stress state determination to ensure a stable configuration, dynamic characterization to ensure resistance to vibrations induced by wind and seismic activity, and practical assembly methods must be established. A full-scale aluminum plate-based tensegrity structure is planned to be constructed over several bike racks on the University of Illinois Urbana-Champaign’s campus. A finite element model has been created of this full-scale bike parking canopy. From this, the first five mode shapes and eigenfrequencies are obtained to characterize the dynamic response of the canopy structure and plate tensegrity roof. It is reasonable to truncate the analysis at mode five as the increasingly higher eigenfrequencies contribute less to the overall structural response. Results show that eigenfrequencies are sufficiently high to be beyond the risk of resonance for wind and seismic activity. The number of self-stress states for a single module and full-scale roof is also determined through the construction of the equilibrium matrix. The existence of multiple self-stress states indicates a stable configuration of the structure. Lastly, possible solutions for the joints needed to construct plate-based tensegrity structures have previously been presented in literature. However, none of these proposed solutions have been tested or manufactured. Modified joint designs which are easy to fabricate are proposed in this work, and documentation for the assembly is outlined. This paper presents previously unaddressed self-stress, dynamic, and joint design considerations for plate-based tensegrity structures. Results will further advance the practical design and construction of plate-based tensegrity structures.