Sensitivity analysis of hydrodynamic journal bearing failure modesdue to lubricant contamination

This study focuses on the sensitivity analysis of failure modes in an hydrodynamic journal bearing, taking into account lubricant oil contamination.Two sensitivity analysis methods are employed to investigate hydrodynamic (HD) performance in the presence of a circumferential scratch on the shaft surface.The Morris method considers multiple input parameters of the numerical bearing model.A One-At-a-Time (OAT) design of experiments is used to evaluate the model's performance.The analysis classifies the parameters into three groups: those with nonlinear effects and strong interactions, those with linear and moderate effects, and those with negligible impact.The second method is based on variance decomposition and the calculation of Sobol indices, using a Kriging surrogate model built from a Latin Hypercube Sampling (LHS) design.The results obtained from both methods help reduce the stochastic dimensionality of the hydrodynamic bearing reliability problem by treating the least influential parameters as deterministic.The study focuses on the variability of the key factors that significantly affect the minimum lubricant film thickness and the maximum pressure in the bearing.