Semi-Active Vibration Isolation Using Fluidic Flexible Matrix Composite Mounts

Author(s):  
Michael Philen

Variable modulus fluidic flexible matrix composites (F2MC) are investigated for vibration isolation mounts. The fluidic flexible matrix composites are based upon flexible matrix composite tubes containing a high bulk modulus internal fluid. By tailoring the fibers (orientation, number of layers, material, etc.) and the choice of the matrix material, the F2MC tube can obtain significant changes in stiffness by simply opening or closing an inlet valve to the tubes. The objective in this research is to investigate the F2MC variable modulus system for semi-active vibration isolation. A nonlinear analytical model of an isolation mount based on the F2MC tube with a proportional valve is developed. Analysis results indicate that the F2MC based isolation mount is effective for reducing the transmission from a disturbance source to a mass. Simulation studies demonstrate that the resonant frequencies and the damping can be controlled through simple valve control, which can be effective for vibration isolation.

2011 ◽  
Vol 23 (3) ◽  
pp. 353-363 ◽  
Author(s):  
Michael Philen

Variable stiffness f2mc are investigated for vibration isolation through analysis and experiments. The f2mc are novel structures that have been shown to achieve significant changes in stiffness through simple valve control. The objective of this research is to develop analysis tools to investigate the f2mc variable modulus system for semi-active vibration isolation and to validate the results through experiments. A non-linear analytical model of an isolation mount based on the f2mc tube with a proportional valve is developed. Analysis results indicate that the f2mc-based isolation mount is effective for reducing the force transmitted to the foundation and that the transmissibility ratio can be tuned via proportional valve control. Experimental results agree with analysis results and validate semi-active vibration isolation using a proportional valve.


2021 ◽  
Vol 11 (10) ◽  
pp. 4526
Author(s):  
Lihua Wu ◽  
Yu Huang ◽  
Dequan Li

Tilt vibrations inevitably have negative effects on some precise engineering even after applying horizontal and vertical vibration isolations. It is difficult to adopt a traditional passive vibration isolation (PVI) scheme to realize tilt vibration isolation. In this paper, we present and develop a tilt active vibration isolation (AVI) device using a vertical pendulum (VP) tiltmeter and a piezoelectric transducer (PZT). The potential resolution of the VP is dependent on the mechanical thermal noise in the frequency bandwidth of about 0.0265 nrad, which need not be considered because it is far below the ground tilt of the laboratory. The tilt sensitivity of the device in an open-loop mode, investigated experimentally using a voltage controller, is found to be (1.63±0.11)×105 V/rad. To compensate for the hysteresis nonlinearity of the PZT, we experimentally established the multi-loop mathematical model of hysteresis, and designed a parallel controller consisting of both a hysteresis inverse model predictor and a digital proportional–integral–differential (PID) adjuster. Finally, the response of the device working in close-loop mode to the tilt vibration was tested experimentally, and the tilt AVI device showed a good vibration isolation performance, which can remarkably reduce the tilt vibration, for example, from 6.0131 μrad to below 0.0103 μrad.


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