Identification of Dynamic Bearing Parameters: A Review

Abstract

In this paper, we present a review of the experimental identification of dynamic parameters of bearings in a rotating machine. Major emphasis is given to vibration-based identification methods and the review encompasses descriptions of experimental measurement techniques, mathematical modeling, parameter extraction algorithms and uncertainty in the estimates applied to a variety of bearings. The parameter extraction algorithms include the descriptions of governing equations of the rotor-bearing system and identification methods in both time and frequency domains. The identification techniques have been classified based on methods used to excite the system. The review includes a variety of bearings and similar components, which play an active link between the rotating and stationary parts of a machine. Based on the state of the art in bearing identification, conclusions are made and future directions are suggested.

Comparison of Perturbed Reynolds Equation and CFD Models for the Prediction of Dynamic Coefficients of Sliding Bearings

“…∂ẏ ∆ẏ or p ≈ p 0 + p y ∆y + pẏ∆ẏ into the Reynolds Equation (1). Note that the bearing dynamic response is assumed to be linear and only linear terms in the series expansion of pressure are retained.…”

“…The proposed method is analogous to experimental methods of Tiwari et al [1] used to determine the dynamic coefficients wherein a sinusoidal perturbation (input) is correlated with the corresponding transient force (output) of the bearing. The results obtained with this method are compared first for a self-acting linear slider bearing and pure squeeze motion between parallel plates.…”

The Experimental Identification of the Dynamic Coefficients of two Hydrodynamic Journal Bearings Operating at Constant Rotational Speed and Under Nonlinear Conditions

“…Values of stiffness and damping coefficients of hydrodynamic bearings are the most important from the point of view of dynamical performance [12,13]. Because of many difficulties in numerical modelling, many experimental methods for determination of their values have been proposed [9,21]. Experimental investigations were performed with different types of bearings.…”

Experimental Estimation of Journal Bearing Stiffness for Damage Detection in Large Hydrogenerators

“…The lower bearing is a combined thrust and journal bearing, constituted by the generator lower shaft (4), the thrust block and pads (7), and the thrust bearing bracket (10). The turbine bearing is composed of the turbine shaft (5), pads (8), and turbine headcover (11). Table 1 presents the main data of these journal bearings [10].…”

“…Tiwari et al [11] consider that the theoretical estimation of bearing dynamic coefficients "has always been a source of error in the prediction of rotor-bearing systems," mainly due to the difficulties of determining bearing operating conditions accurately. This problem is worse in vertical rotating machines, like LHG.…”