Design And Experimental Research Of Frequency Tunable Vibration Isolators Based On SMA

Spotlights have been focused on vibration control in the domains of aeronautics and astronautics.Due to dynamic complexities and stringent safety requirements,prominent emphasis is laid on vibration suppression.Launch vehicles,which suffer from severe dynamic loads during flight phases,are generally equipped with shock isolators in order to attenuate the effect of severe shock environments.However,these isolators could amplify the low-frequency vibration generated by the engine thrust and aerodynamic loads,which could give rise to degradation of payload stability.To solve this problem,a novel design of shock isolators is proposed in this thesis,in which shape memory alloys are adopted as actuators and mental rubbers are employed as vibration isolation elements.The stiffness of mental rubber is sensitive to compression displacement,which facilitates vibration isolator to change its natural frequency.The main research works and results of this thesis are as follows:(1)The constitutive relations of shape memory alloys are investigated and mechanical properties are tested by experiment.Simultaneously,two methods of integral analysis are discussed.(2)Metal rubbers of different parameters are manufactured and the damping models of metal rubbers are discussed.Moreover,the compressive mechanical properties of metal rubber are researched by mechanics experiments.(3)The overall structure design of the frequency tunable vibration isolator is proposed,which based on studying of dynamics principles of vibration isolators.Additionally,the specific parameters of frequency tunable vibration isolator are validated and the processing and assembling of frequency tunable vibration isolator are demonstrated.(4)The vibration experiment project is designed in order to test the vibration isolators using mental rubbers of different parameters.The performance test of frequency tunable vibration isolator is implemented.Finally,the effectiveness of the vibration isolator is demonstrated.