Nonlinear Analysis of Dynamic Characteristics of Cylindrical Bearing Oil Film

The discrepancy between calculated and measured oil film coefficients of a plain journal bearing, especially in the region of high eccentricity ratio, has been addressed by various approaches (e.g., THD analysis). Judging from previous reports, these efforts to explain the causes of such a discrepancy are insufficient. In this work, we studied the relationship between the bearing oil film dynamic characteristics and the boundary condition for oil film pressure generation. The results indicate that on assuming the squeeze oil film pressure effect is effective only when the rotor shaft approaches the bearing metal, the damping coefficients more closely match the experimental values than the conventionally calculated values.