Double-notch single-pumper fluid mounts

Passive fluid mounts are widely used in the automotive and aerospace applications to isolate the cabin from the engine noise and vibration. In the case of aerospace fixed wing applications, when fluid mounts are used, they are placed in between the engine and the fuselage, and the notch frequency of each fluid mount is tuned to either N1 frequency (engine low speed shaft imbalance excitation frequency) or to N2 frequency (engine high speed shaft imbalance excitation frequency) at the cruise condition. Since current passive fluid mount designs have only one notch, isolation is only possible at N1 or at N2, but not both. Here, in this paper, a double-notch passive fluid mount design will be presented, which has two notch frequencies, and therefore can provide vibration and noise isolation at two frequencies. In this paper, the new fluid mount design concept and its mathematical model and simulation results will be presented.