| With space mission developing toward the direction of variety and complexity,traditional damping technology which the high precision instrument and equipmentsensitive of spacecraft need to can not be met the requriement of harsh dynamicenvironment. Nonlinear energy sink is a new damping device which is differentfrom linear vibration absorber. The mechansim of vibration suppression is targetedenergy transfer, it has charateristies of high efficiency, stong robustness and so on.Nonlinear vibration absorption provide a new approach for the suppression ofspacecraft parts or componets. Based on this background, several mechanicalproperties of single degree-of-freedom nonlinear energy sink is studied in thisthesis.The time of decreasing energy is an important evaluation index of vibrationsuppression ability of nonlinear energy sink. First, the complex-averaging method isused to anlysis the energy dissipation of linear oscillator. Based this method, therelationship between the energy and structure parameters of system is obtained.With the time of decreasing energy of linear oscillator at the same condition iscompared, the conditions are obtained that nonlinear energy sink must be satisfied.Numerical simulations has confirmed results at last.Next the mechanical properties of nonlinear energy sink which has compositestiffness form is investigated, when the damp must the conditions that targetedenergy transfer need to meet. First, it has analysed the nonlinear stiffness impactingon energy transfer and get the mass of ratio of nonlinear energy sink for realizingtargeted enegy transfer in the conservative system. At the same time, the nonlinearstiffness which impacted on the disspption of energy is discussed innon-conservative system. And it obtain the effective range of stiffness at last.Applied a narrow-band random excitation in the sytem coupling nonlinearenergy sink, it’s investigate how nonlinear vibration absorber influences of abilityof vibration suppression under random excitation. The method which thecomplex-averaging combined with the tuning parameters is used and get the slowdynamics of system, and analyses the incentive intensity corresponding charateristies of response and obtains that strongly modulated response must meetconditions.It also studys on the disturebance intensity effecting on the efficiency ofvibration suppression using the equivalent linearization and the pseudo excitationmethod.We confirm this results at the end of article. |
