Vibration and damping in three-bar tensegrity structure

The most interesting examples of tensegrity structures are underconstrained and display an infinitesimal flex. In the direction of that flex the force -displacement relationship is highly nonlinear, resulting from geometric st iffening and influenced by the effect of prestress at equilibrium. A tenseg rity structure would therefore display nonlinear vibrations when excited in the direction of the infinitesimal flex, the "frequency" decreasing with a mplitude. Movement in the direction of the flex occurs with only infinitesi mal change in member length, and therefore under conventional models of mat erial damping in members the motion would not vanish as rapidly as it would for a conventional oscillator. We study one particular tensegrity geometry for which we present the force-displacement relationship in analytical for m and then examine the nonlinear vibrations. We observe the role of damping and we discuss those implications for the design of tensegrity structures in space applications.