On self-equilibrium state of V-expander tensegrity beam-like grids

Tensegrity structures are an innovative class of lightweight structures, which have gained the interest of researchers in many different fields, including but not limited to engineering. In particular, such interest is due to their aesthetic value, their large stiffness-to-mass ratio, the possible deployability, together to their reliability and controllability. Tensegrity structures, made of struts in compression and cables necessarily in tension, are innovative structures by itself: they are similar only in appearance to conventional pin-joint structures (trusses), and their mechanical behavior is strongly related to initial feasible self-stress states induced in absence of external loads. In particular, from a kinematical point of view, these self-stress states avoid the activation of possible infinitesimal mechanisms. In this paper, we study an innovative class of tensegrity beam-like grids, obtained by a suitable assembly of three elementary V-Expander tensegrity cells along a longitudinal axis (named x-axis) in the three-dimensional space. In particular, by means of a numerical study, we analyze the feasible self-stress states for seven tensegrity beam-like grids, with increasing degree of complexity, made by an arrangement of V-Expander elementary cells. Moreover, we analyze the influence on the feasible self-stress states of the addition of elements starting from the simplest V-Expander tensegrity configuration.