A Novel Variable Impedance Hydrodynamic Oil-Film Bearing: Part 2: Experimental Identification of the Steady State and Dynamic Characteristics

Abstract

A novel form of hydrodynamic oil-film bearing has been examined experimentally to establish both steady state and dynamic characteristics. The novel bearing design is based on a 120° partial arc bearing but contains two recesses to which are attached accumulators. The facility to open or close a valve located between the accumulator and the recesses enables the engineer to effectively tune the bearing in situ. This bearing also has the benefit of being similar in cost to a standard bearing. The oil-film coefficients were obtained from the frequency response function obtained when the system was excited by a pseudo random binary sequence signal. The use of the generalized matrix inversion method to determine the oil-film coefficients from the frequency response function was found to be some 10 per cent faster than the least squares curve-fitting method. Both methods were shown to produce reliable estimates to extract oil-film coefficients.

Keywords

hydrodynamic oil-film bearing accumulators oil-film coefficients frequency response function generalized matrix inversion least squares curve fitting

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