On the Robustness of Tensegrity Systems Subjected to Local Damage

Tensegrity systems are structures in equilibrium under a self-stress state prior to the application of external loads. Such self-stress state is the result of the superposition of self-stress basis vectors. Tensegrities have complex nonlinear behavior when subjected to external actions (loads or imposed displacements). In this work, the robustness of this particular structural typology is evaluated by numerical simulations. Robustness is the ability of a locally damaged structural system not to behave in a manner disproportionate to the original failure, i.e., the insensitivity to local damage. This concept and its insights have been thoroughly analyzed for several structural systems, as in the case of frame structures. To date, limited studies have been performed on the robustness of tensegrity systems to unexpected conditions. Among the potential damages, one can consider the settlement of one of the supports, the reduction of prestress and the failure of one of the cables. The present study reports the results of a set of damage simulations on a simple T-3 prismatic tensegrity structure. Several risk factors are considered to study the response of the structure to unexpected damage. In particular, the tensegrity configuration is subjected to different stress loss in the constituent elements. The results are obtained through simulations performed in MSC.visualNastran 4D (vN4D), which run dynamic simulations by merging CAD, motion, FEA, and controls technologies into a single functional modeling system. The models were established to obtain different equilibrium configurations and conditions of loss of equilibrium, with the corresponding large displacements measured for the most significant points of the structure, assumed as markers for the resulting effects on the structure.