Influence of Manufacturing Variation on the Dynamic and Tribological Performance of Tilting Pad Journal Bearings

Abstract

A systematic approach of a Tilting Pad Journal Bearing (TPJB) as a whole tolerance stack up assembly is presented. Normal component variation within actual design tolerances is considered. The vector loop is expanded via Taylor series for sensitive analysis. The bearing shell and tilting pad machined radiuses for each pad are found to be the more influential dimensional characteristics on the assembled clearance and preload. A leading edge relief was used to avoid unloaded pads fluttering, while maintaining a satisfactory bearing assembled clearance in the loaded pads throughout the resultant preload variation. Pivot flexibility and preload loss due to pad wear in service life were considered in the preload variation assessment. Surface response multivariate multi-response models were built for a 4-pad TPJB under Load Between Pad (LBP) and Load On Pad (LOP) configurations. Desirability functions rendered the maximum and minimum rotordynamic coefficient and tribological parameter responses across speed. The LOP configuration showed more variation in the direct rotordynamic coefficients, while the LBP configuration indicated more sensitive cross-coupled coefficients with strong sign change in some cases. Among the tribological performance parameters, the eccentricity and pad maximum pressure were more affected, followed by the minimum film thickness, and weakly by the power loss, and oil film temperature. The dispersion of the tribology parameters under normal manufacturing variation is found of importance. Four, and seven extreme geometrical state cases were identified for the LBP, and LOP bearing configurations, respectively.

Probing asymmetric uncertain effect on symmetric three-lobe journal bearing

“…After obtaining the coefficient matrix C, the value of the output function at any input value can be computed from equation (31).…”

“…It was only in the last few years that uncertainties called the attention of Engineers and Researchers. Some recent studies [29][30][31][32][33][34][35] have considered the input uncertainty in the hydrodynamic analysis of journal bearings. da Silva et al 29 considered stochastic variation in bearing clearance and Griffini et al 30 considered the stochastic variation in bearing clearance as well as fluid viscosity to study the dynamic response of tilting pad bearings.…”

“…da Silva et al 29 considered stochastic variation in bearing clearance and Griffini et al 30 considered the stochastic variation in bearing clearance as well as fluid viscosity to study the dynamic response of tilting pad bearings. Whereas Urbiola-Soto 31 studied the uncertain behavior of tilting pad bearings arises due to the stochasticity in the radius of the bearing shell and tilting pads. Cavalini et al 32 and Maharshi et al 33 performed the dynamic analysis of plain journal bearing wherein, Cavalini et al considered the variation of the input parameters based on fuzzy logic whereas, Maharshi et al used the stochastic variation of the input parameters.…”

Experimental Study on Low Speed Lubrication Characteristics of Large Tilting Pad Bearings

“…Bearing performance is improved by optimizing bearing structural parameters such as tile wrap angle [10] , aspect ratio [11] , bearing clearance [12] , pivot position [13] and pivot flexibility [14][15] [16] . Over the years, a large number of theoretical and experimental studies have provided an important assessment basis for the design and reliability application of tilting pad bearings, forming a common knowledge support [8] [9] .…”