The development of a tunable vibration absorbing isolator

This paper describes a tunable vibration absorbing isolator. The device is based on the liquid inertia vibration eliminator, which is modified so that the frequency at which maximum isolation occurs can be changed in real time. This is achieved by using adjustable pneumatic springs. A theoretical model describing the device is derived using Lagrange's equations. The model is used to design a practical device and experimental results confirm the validity of the model. With the experimental device a roll-off of about 90 dB/decade over a 12 Hz frequency band was achieved.