ENERGY TRANSFER AND DISSIPATION IN STRUCTURES WITH DISCRETE NONLINEARITIES

The dynamics of space structures with discrete, non-hysteretic, nonlinear, joints are analytically and experimentally investigated. The structures are modeled as long thin beams with a single discontinuous joint at its center. The joints are piecewise linear in nature and represent joints of asymmetric stiffness and joints with dead-band. The nonlinear joint causes energy to be transferred among structural modes. The apparent damping of the modes can therefore change. The beam's damping due to modal coupling is calculated as a function of the beam and joint parameters. An experiment is developed which measures damping while jointed beams are lofted in vacuum to simulate weightlessness and the vacuum of space. The experiments are designed to confirm the analytical model. An analytic model is developed to model space structures as continuous, damped, engineering beams and a piecewise linear joint. The use of continuous models eliminates the possibility of trapping energy in the lowe