Dynamic Model And Parameter Identification Of A Rubber And Wire-cable Composite Vibration Isolator

With the development of economy and the progress of the society, scientific researchers and technical staffs pay more attention to vibration control technology. Isolation is one of the most important research fields of vibration control. Harmful vibration can be isolated by isolation system to keep other instruments working safely. Vibration isolator is the core component of the isolation system. The property of vibration isolator plays a decisive role in the whole performance of vibration isolation system. Basing on the isolation behavior test with an electro-dynamic shaker, the dynamic model for a passive rubber and wire-cable composite vibration isolator is developed and the parameters are identified.The recent development and progress of the isolation technology is firstly introduced in this paper. And several common passive vibration isolators are introduced. The new vibration isolation (rubber and wire-cable composite vibration isolator) has emphatically introduced. In the dynamic modeling process, the method of Hilbert transform on the testing transmissibility curves is used to examine the nonlinearity of the system. The nonlinear characteristics of the rubber and wire-cable composite vibration isolator can be found through the Hilbert transform. Basing on the comparison of the transform curves and the test curves at different excitation amplitudes, and researching on the structure characteristic of composite isolator, nonlinear cubic stiffness dynamic equation for the isolator is established.The non-linear function that describes the dynamic behavior of the system is converted to the series of linear functions of the unknown parameters by using the separation recognition method, which changes the nonlinear problem into the linear problem that is easy to be deal with. On this basis, the least square method is used to identify the stiffness and damping parameters at different measurement conditions.When the parameters have been identified, the fourth-order Runge-Kutta method with a step-size controlled algorithm and harmonic balance method are used for numerical and analytical analysis of the nonlinear dynamic equation of the composite isolator respectively. The numerical and closed-from results for the identified system obtained by the numerical and harmonic balance methods are compared well with the testing results obtained by stepped-sine method. It is shown that the nonlinear dynamic model is suitable for the rubber and wire-cable composite vibration isolator.