Statistical analysis of tilting pad journal bearing dynamic coefficients: influence of measurement uncertainty

Dynamic coefficients of tilting pad journal bearings are typically determined by measuring forces and displacements in experimental tests. A methodology developed by the authors determines the dynamic coefficients by minimizing the sum of the squared residuals of displacements and forces, normalized with the uncertainty associated with the measurements themselves, that is the standard deviation of the population of measurements (Fig. 1). In this paper, we analyze the influence of the choice of such normalization. In previous works [1], standard deviations have been defined on the Cartesian coordinates in the complex plane of the displacement and force phasors. An alternative methodology defines the standard deviations on the polar coordinates of such phasors. We discuss the influence of the standard deviation values on the results of the minimization algorithm.