Dynamics Research On Magnetorheological Damper Ship Isolation System

The vibration damping and noise reducing of ships auxiliary machine systems has always become a research focus worldwide, although the traditional passive control was widely used in industrial control, it’s vibration isolation performance could not be regulated according to the variation of the complex load. The semi-active vibration isolation has good application foreground based on MR damping technologies.This paper used an improved Bingham plasticity model to describe the model of the MR damping force and experiments are performed to testify the model. Established the auxiliary semi-active single or double layer vibration isolation system’s equations of motion according to the theories of vibration isolation. Semi-active nonlinear vibration isolation system was studied in the main resonance characteristics, used average method to get an approximate solution of nonlinear system, numerical solution are shown to illustrate the validity. The effect of some parameters of the isolation system to the main resonance characteristics is analyzed. The analysis has shown that Using average method to get the theoretical solution and numerical solution has good consistency; In the semi-active nonlinear vibration isolation system’s the main resonance region: Zero speed force has an less effect on primary resonance domain of semi-active vibration isolation system, the influence of the amplitude frequency response is quite obvious when MR dampers’ damping and control force was working on the semi-active vibration isolation system. The semi-active vibration isolation system’s the amplitude frequency response amplitude are significantly reduced with the increasing of damping and control force. In the non resonance region: the influence of damping, control force and zero speed force to system response is smaller.In view of the auxiliary semi-active single-layer, double-layer vibration isolation system and the floating raft isolation system, established Simulink model of system according to the equations of motion, the influence of semi-active control, the semi-active switch control, semi-active relative control, the improved semi-active relative control and other control strategies with MR control force, the stiffness of vibration isolator, excitation frequency and other system parameters to the performance of vibration isolation system is analyzed, a large number of simulation analysis was conducted, the semi-active vibration isolation system and the traditional passive vibration isolation system’s vibration isolation performance are analyzed in comparison. The results shown as followed:(1)Due to the nonlinear characteristics of the MR damper, control force was not in proportion on the effects of vibration isolation system, a little change of the parameters may cause significant change of vibration isolation effect in some cases.(2)The stiffness of vibration isolator also has an evident effect on the vibration isolation performance, curves present a parabolic rate law under certain control strategy, vibration isolation effect is better at high frequencies.(3)The semi-active control system’s vibration isolation effect is superior to the passive control with the steady state response.