Vibration Suppression Of Translating Appendages Of Spacecraft Based On Nonlinear Energy Sink Theory

Axially translating structures are widely used in the spacecraft,they are folded,when the spacecraft being launched.After the spacecraft gets into the scheduled orbit,these structures will be gradually unfolded.However,the vibration of the spacecraft induced by the deployment of these appendages has an influence on the control accuracyof the spacecraft and even lead to a instability.So it is of great importance to deploy researches on the dynamic characteristics of the axially translating structures.In this study,we employed an axially translating laminated composite cantilever beam,considering shear deformation and longitudinal displacements of the beam,to simulating the axially translating appendages of a spacecraft.And we have done some extensive research on the dynamic characteristics of axially translating beam based on the previous studies.Finally,we employ a Nonlinear Energy Sink to suppress the vibration of the beam and make an explanation of the vibration suppression effects based on the Target Energy Transfer theory.The major aspects of our study can be concluded as follows.1.We derived the governing equations of the system from constitutive relations and the Hamilton principle.And we get the discretized equations withtime dependent coefficientsof the system with the aid of the modified Galerkin method.2.We have analysed the dynamic behavior of the axially translatingbeam with the use of numerical method.By using Differential Quadrature Method(DQM),we hve analyzed the relationship between naturalfrequencies of the beam and the deploying rates.The fourth order Runge–Kutta method is employed to demonstratethe transient response of the tip displacements of the beam under different translating rates.And we have derived the stability boundary inside which the beam keeps dynamic stable.3.The numerical method is used to demonstrate the effect of vibration suppression for the beam at different prescribed time-variant translating velocities.The dynamic behavior of the axially translating beam with and without a nonlinear energy sinkattached iscomparedfor several cases of different axially translating velocities.And we also have given some illustration of the irreversible energy pumpingphenomenon.