PASSIVE VIBRATION REDUCTION OF SPACE TRUSS STRUCTURES BASED ON NES

The discrete linear spatial truss structure composed of many bar members is taken as a continuous beam by using an equivalent method. The transient vibration suppression of the truss structure is studied by adding nonlinear energy sinks (NES) to the equivalent beam. The lattice structure of the beam is modeled as an equivalent linear continuous system (finite length beam) by an equivalent method, which is verified by a finite element model. The vibration control equations of an equivalent cantilever beam with a NES attachment are established. The Galerkin method is adopted for discretization. The displacement responses of beams with and without a NES attachment under external excitation are analyzed. The vibration suppression effect of NES on the structure is studied by calculating the external excitation response of NES attachments at different positions in the structure. In addition, the external excitation response of NES attachments with different masses at different positions are also investigated. The effect of NES additional mass on the vibration reduction is obtained. The results show that the NES attachments can reduce the response efficiency of the x-truss under transient excitation When the mass of the NES attachments increases, the vibration amplitude of the system declines more rapidly and the energy consumption efficiency of the NES attachments becomes higher. The NES passive vibration reduction effect is compared with the linear stiffness damping damper (TMD). The results show that, in the structure with additional NES, the attenuation of the structure amplitude is appreciable at about 5 seconds after the excitation occurred, and the decline in the amplitude is steeper. This means that the NES passive reduction effect is much better than that of the linear stiffness damping damper (TMD). Additionally, the attenuation effect of the NES attachments with different qualities is verified through experiments, in which the same displacement excitation amplitude (15 mm) is applied to the free end of a beam. The results show that the greater the mass of the NES attachment is, the higher is the attenuation efficiency of the transient response of the cantilever structure. The experimental results are in good agreement with the theoretical calculation results.