THE VIBRATION DAMPING EFFECT OF AN ELECTRORHEOLOGICAL FLUID

The attenuation of longitudinal vibrations in structures can be achieved through a change in the impedance of the structure. This impedance change can be produced by an electrorheological fluid. The transmission of a known vibration input along a test structure will be correlated to the impedance characteristics of the electrorheological fluid. This impedance characteristic of the fluid will be expressed in terms of the applied electric field. The attenuation characteristics of the electrorheological fluid on longitudinal vibration have been presented through experimental and numerical results. The results of this study showed an attenuation of 4 dB in the transmissibility of acceleration from the forward to the aft ends of the test structure. This level can be increased by using a fluid possessing a lower zero state viscosity. A secondary result of this investigation is understanding the physics of the damping mechanism in the test module when the electric field was increased from 1.2 kV/mm to the value of 1.6 kV/mm. During this increase in the electric field, the logarithmic decrement increased by more than a factor of three. The transmissibility data also shows that the resonant frequency decreased.