SUBJECT: M.S. Thesis Presentation
BY: Elliott Gruber
TIME: Wednesday, March 27, 2013, 2:00 p.m.
PLACE: Love Building, 109
TITLE: Optimal Configuration of Adjustable Hydraulic Noise Suppressors
COMMITTEE: Dr. Kenneth Cunefare, Chair (ME)
Dr. Wayne Book (ME)
Dr. Mardi Hastings (ME)


Hydraulic systems that operate over a broad range of load pressures pose challenges for suppression of fluid-borne noise. A common type of noise control device, a bladder-style suppressor, performs well only over a relatively narrow range of load or system pressures. This thesis considers the problem of finding the optimal charge pressure(s) in either a single suppressor or two suppressors in series for maximum fluid-borne noise suppression in a weighted sense. The transmission loss, a measure of pressure ripple (dynamic pressure fluctuation) reduction, for the suppressors is predicted by an equivalent fluid model. The optimum configuration is sought through maximization of an objective function. The objective function is a summation of weighted transmission losses, where the weighting captures the duty cycle of the load pressure through a time weighting factor, and frequency weighting factor captures the spectral content of the pressure ripple. The duty-cycle weighting biases the objective function toward the most-used pressures. The frequency weighting emphasizes the high-energy spectral components in the target pressure ripple at a given load or system pressure. Optimal configurations are found for a set of system pressures, load pressures and duty cycles. It is found that the time weighting has a more significant impact on the optimum charge pressure than the frequency weighting, as seen by duty cycles considered in this thesis.